GMT
  • LOGIN
    Sign in with Facebook
  • |
  • SIGNUP
Our Community
Latest Jobs
Latest Videos
Our Blog
Forum
Latest Events
CLOSE
  • Home
    Home This is where you can find all the blog posts throughout the site.
  • Categories
    Categories Displays a list of categories from this blog.
  • Admin's Log
    Admin's Log
  • Tags
    Tags Displays a list of tags that have been used in the blog.
  • Bloggers
    Bloggers Search for your favorite blogger from this site.
  • Team Blogs
    Team Blogs Find your favorite team blogs here.
  • Login
    Login Login form

Maritime Blogs

Blogs by Maritime Community

ANAND VARDHAN TIWARY
ANAND VARDHAN TIWARY
<div class="cStream-Attachment-inner-custom"><div><div style="float:left; width: 130px;margin-right: 12px;float: left;color: transparent;"><a href="/www.theweek.in/content/dam/week/news/india/images/2019/1/23/…; target="_blank"><img src=www.theweek.in/content/dam/week/news/india/images/2019/1/23/… style="width: 200px;height: auto;" /></div><div style="width: 75%;float: left;"><div style="font-weight: bold;font-size: 18px;margin: 0 auto 2px auto;"><a href="/www.theweek.in/news/india/2019/01/23/…; title="www.theweek.in/news/india/2019/01/23/…; target="_blank">6 Indian sailors killed, 6 missing in Kerch strait ship accident</div><div style="margin: 0 auto 8px auto;">Two fuel ships carrying Indian and Turkish crew members caught fire in Kerch Strait</div></div></div></div>

Marine professionals (surveyors, designers, naval architects etc) operating in any of the marine industries as independent contractors should endeavour to limit their exposure to claims by ensuring that their terms and conditions incorporate suitable limitations on their liability. This is so whether the work being done relates to luxury yachts, commercial ships or floating drilling and production equipment for use offshore in exploration and production activities and should be done irrespective of the scale and value of the specific project.

The incidence of claims being brought against marine professionals is on the increase. In particular projects involving the conversion or upgrading of a ship, have become more involved and more complex. Delays and cost overruns have become common place with such projects over the years, with parties seeking to allocate responsibility for the consequences. Lack of front end preparation has been identified as the key cause of losses. As a result heavier reliance is now placed upon marine professionals with regard to suitability studies, surveys and design/scheduling at the beginning of the project.

What a marine professional is able to achieve by agreement with his client in limiting his liability will largely depend upon the market and, in particular, what the competition are offering. Rarely, however, will a marine professional be selected for work on the strength of his willingness to assume liability for his negligence!

As a starting point, it is clearly appropriate for a marine professional to limit his liability overall – he is essentially a provider of services and advice. He is not bearing the risk (or rewards) of the project; he has no equity interest. His financial interest is capped at the level of his potential or actual fees. Thus any liability he may assume for any losses arising from the services and advice provided should be limited to a sensible and reasonable amount in the circumstances.

Further, any overall limitation should be co-extensive with the scope of the entire services provided. It should extend to any services beyond the original scope of work whether or not contemplated at the time the contract is made. Otherwise, it may be said that the limitation applies only to the original scope of work and that any new or extra work performed has been undertaken without any such limitation applying.

This raises a practical consideration – marine professionals should not do additional work which is not within the scope of the contract without first ensuring that it is subject to the same terms and conditions as the original scope of work. An addendum to the contract does not merely act as a record of the scope and price for new work but, if correctly drafted, ensures that all of the limitations applying to the original work will apply to any new work. A common theme in claims is that the marine professional is asked to provide further advice and services that evolve from the initial scope of work - as the relationship with the client develops so the level of responsibility and extent of work grows; but this can give rise to an assertion being made later on that the professional ceased to act within the scope of the original contract and that he has assumed new responsibilities in contract or in tort without limit. It is important, therefore, to ensure that extra work or responsibilities are only assumed with written agreement as to the terms, including limitations. This administration ought to be second nature; and sensitivities over the maintenance of client relationships ought not to deter efforts to reach agreement on such matters.

Next, the amount of any overall limitation on liability ought not to be based upon the amount of insurance cover. Clearly, whether a marine professional can insure his risk in the market and the cost to him of any cover is a consideration in undertaking and pricing work; but this should not determine the amount of any limitation he agrees with his client. A marine professional should act as a prudent uninsured would act in negotiating terms.

The amount of any limitation will usually be a pre-agreed fixed sum (say 10% of the total price quoted for the work) or the amount of fees paid for the work. What is acceptable will depend on the circumstances. Classification societies tend to look to agree a cap of 10% of the contract price for their verification services. Designers tend to cap their liability at the fees paid to them, but there is no standard as such.

Finally, turning to the detailed drafting of such clauses, they are occasionally mistakenly prepared on the basis that they are designed to limit any liability for consequential or indirect losses. Such liabilities would routinely (and should in any event) be excluded by a suitable provision. An overall limitation clause acts independently to limit or cap any recourse against the marine professional for direct losses and damages for breach of contract or in negligence to an agreed figure. Direct losses are not narrowly confined and could exclude a claim for loss or profits and other costs that you extend well beyond the cost of merely obtaining alternative services or re-doing the work. It is therefore important that the clause is sufficiently widely drafted to encompass any claim or liability for direct or any other losses “howsoever arising” whether under the contract, in tort for negligence or otherwise. It is also recommended that express reference is made to any liability for breach of any statutory duty to the extent that the same may be limited.

A typical clause might provide as follows (but in all cases specific advice should be obtained):

The aggregate liability of the Consultant to the Company for any matters arising under or in connection with this Agreement (however arising including for breach of contract, in tort, by reason of indemnification, breach of statutory duty, equity or any other legal theory) shall in no case exceed 10% of the Contract Price. This liability limit shall not apply to or be reduced by liability in the case of fraud, fraudulent misrepresentation and/or wilful misconduct.”

Hits: 1112
0

This Blog is intended to provide Maritime Shipping community with guidance on Cargo operation of a Bulk carrier to prevent her hull from getting over-stressed during such period.

A review of the potential problems that could be encountered during cargo operations is discussed. Thus an attempt has been made to provide guidance on the measures that should be taken to monitor and control cargo and ballasting operations in order to reduce the possibility of over-stressing the ship’s structure.

As per various studies conducted by the International Association of Classification Societies (IACS), the principal factors contributing to the loss of the bulk carriers were:

  1. Corrosion and cracking of structure within the cargo spaces.
  2. Over-stressing of the hull structure due to incorrect loading of the cargo holds and
  3. Physical damage to the side structure during cargo discharging operations.

To counter such conditions, several measures were taken by the classification societies ,like Introduction of corrosion protecting requirements for ballast tanks, Implementation of Enhanced survey programme (ESP) for Bulk carriers, requirements for specific approved loading instruments and Publications of various Brochures and Manuals to assist the ship owners to avoid such incidents.

Particular concern is presented by potential problems which may result during operations such as the introduction of very high capacity loading systems, lack of communication between ship and terminal and inadequate planning of cargo operations. The issue that some seafarers, and ship and cargo operators do not have a clear understanding of the limitations imposed by the ship’s classification society regarding the strength capability of hull structure, is also a matter of concern.

Thus, this mega-blog has been structured into Five Sections to take the reader through a proper flow of the argument, namely:

  1. Typical Bulk Carrier Structure
  2. Cargo distributions along the ship’s length
  3. Shipboard Loading Guidance Information
  4. Planning and control of Cargo Loading and Unloading operations on a Bulk Carrier
  5. Potential Problems which may happen during Cargo operations in a Bulk Carrier

Typical bulk carrier structure

The most widely recognized structural arrangement identified with bulk carriers is a single deck ship with a double bottom, hopper tanks, single skin transverse framed side shell, topside tanks and deck hatchways, as illustrated in the three diagrams below.

In general, the plating comprising structural items such as the side shell, bottom shell, strength deck, transverse bulkheads, inner bottom and topside and hopper tank sloping plating provides local boundaries of the structure and carries static and dynamic pressure loads exerted by, for example, the cargo, bunkers, ballast and the sea.

This plating is supported by secondary stiffening members such as frames or longitudinals. These secondary members transfer the loads to primary structural members such as double bottom floors and girders or the transverse web frames in topside and Hopper tanks, etc.

If you refer the figure no. 3, it is evident that the transverse bulkhead structures, unclosing it’s upper and lower stools, together with the cross deck and the double bottom structures are the main structural members which provide the transverse strength of the ship to prevent the hull section from distorting. In addition, if ingress of water into any one hold has occurred, the transverse watertight bulkheads prevent progressive flooding of other holds.

Hull1

 

 

Figure 1 

 

Hull2

 

Figure 2

 

Hull3

 

Figure 3

Design limitations of Hull structure of a Bulk Carrier

All ships are designed with limitations imposed upon their operability to ensure that the structural integrity is maintained. Therefore, exceeding these limitations may result in over-stressing of the ship’s structure which may lead to catastrophic failure.

The ship’s loading manual provides a description of the operational loading conditions upon which the design of the hull structure has been based.

The loading instrument (loadicator software) provides a means to readily calculate the still water shear forces and bending moments, in any load or ballast condition, and assess these values against the design limits.

A ship’s structure is designed to withstand the static and dynamic loads likely to be experienced by the ship throughout its service life.

The loads acting on the hull structure when a ship is floating in calm water are static loads. These loads are imposed by the:

·         Actual weight of the ship’s structure, outfitting, equipment and machinery.

·         Cargo weight.

·         Bunker and other consumable weights.

·         Ballast weight.

·         Hydrostatic pressure (sea water pressure acting on the hull)

 Dynamic loads are those additional loads exerted on the ship’s hull structure through the action of the waves and the effects of the resultant ship motions namely:

·         Acceleration forces

·         Slamming loads- It is induced on the ship’s bottom shell structure forward due to emergence of the fore end of the ship from the sea in heavy weather.

·         Sloshing loads - Sloshing loads may be induced on the ship’s internal structure through the movement of the fluids in the tanks/holds.

Cargo over-loading in individual hold spaces will increase the static stress levels in the ship’s structure and reduce the strength capability of the structure to sustain the dynamic loads exerted in adverse sea conditions.

 

Analysis of Shear Forces and Bending Moments on Hull Girder

All the Bulk carriers are assigned permissible still water shear forces (SWSF) and still water bending moments (SWBM) limits, by their Classification Society.

There are normally two sets of permissible SWSF and SWBM assigned to each ship, namely:

1.        Seagoing (at sea) SWSF and SWBM limits.

2.        Harbour (in port) SWSF and SWBM limits.

The SWSF and SWBM limits are not to be exceeded when the ship puts to sea or during any part of a seagoing voyage.

In harbour, where the ship is in sheltered water and is subjected to reduced dynamic loads, the hull girder (a ship’s hull is like a beam/girder which is non-uniformly loaded and non-uniformly supported) is permitted to carry a higher level of stress imposed by the static loads. The harbour SWSF and SWBM limits are not to be exceeded during any stage of harbour cargo operations.

When a ship is floating in still water, the ship’s lightweight (the weight of ship’s structure and its machinery) and deadweight (all other weights, such as the weight of the bunkers, ballast, provisions and cargo) are supported by the buoyancy force acting upwards on the exterior of the hull.

Along the ship’s length there will be differences in the vertical forces of buoyancy and ship’s weight. The unbalanced net vertical forces acting along the length of the ship will cause the hull girder to shear and to bend, as shown in figures 4,5 and 6, inducing a vertical still water shear force (SWSF) and still water bending moment (SWBM) at each section of the hull.

 

Hull4

 

At Sea, the ship is subjected to cyclical shearing and bending actions induced by continuously changing wave pressures acting on the hull. These cyclical shearing and bending actions give rise to an additional component of dynamic, wave induced, shear force and bending moment in the hull girder. At any one time, the hull girder is subjected to a combination of still water and wave induced shear forces and bending moments.

The stresses in the hull section caused by these shearing forces and bending moments are carried by continuous longitudinal structural members. These structural members are the strength deck, side shell, bottom plating and longitudinal, inner bottom plating and longitudinal, double bottom girders and topside and hopper tank sloping plating and longitudinal, which all together are generally defined as the Hull girder.

Examples of permissible and calculated SWSF and SWBM are shown in figures 7 & 8 respectively.

 

Hull5

 

Hull6

 

Local Strength of Transverse Bulkhead, Double bottom and Cross Deck Structure

To further enhance safety and flexibility, some bulk carriers are provided with local loading criteria which define the maximum allowable cargo weight in each cargo hold, and each pair of adjacent cargo holds (i.e. block hold loading condition), for various ship draught conditions.

The local loading criteria are normally provided in tabular and diagrammatic form.

Over-loading will induce greater stresses in the double bottom, transverse bulkheads, hatch coamings, hatch corners, main frames and associated brackets of individual cargo holds, as depicted in figure 9.

The double bottom, cross deck and transverse bulkhead structures are designed for specific cargo loads and sailing draught conditions. These structures are sensitive to the net vertical load acting on the ship’s double bottom. (The net vertical load is the difference between the vertical downward weight of the cargo and water ballast in the double bottom and hopper ballast tanks in way of the cargo holds and the upward buoyancy force which is dependent on the ship’s local draught.)

Overloading of the cargo hold in association with insufficient draught will result in an excessive net vertical load on the double bottom which may distort the overall structural configuration in way of the hold, as depicted in figures 10 & 11.

 

Hull7

Hull8

 

A typical Local Loading Diagram for a cargo hold (strengthened hold) combined with the adjacent hold limits, of a bulk carrier is shown in figure 12.

The important trend to note from the local loading diagram is that there is a reduction in the cargo carrying capacity of a hold with a reduction in mean draught. Exceeding these limits will impose high stresses in the ship’s structure in way of the over-loaded cargo hold. There are two sets of local loading criteria depending upon the cargo load distribution namely, individual hold loading or two adjacent hold loading.

The allowable cargo loads for each holds or combined cargo loads in two adjacent holds are usually provided in association with empty double bottom and hopper wing tanks directly in way of the cargo hold. When water ballast is carried in the double bottom and hopper wing tanks, the maximum allowable cargo weight should be obtained by deducting the weight of water ballast being carried in the tanks in way of the cargo hold.

The maximum cargo loads given in the Local Loading Criteria should be considered in association with the mean draught in way of the Cargo holds.

Hull9

 

Cargo distributions along the ship’s length

Bulk carriers are designed and approved to carry a variety of Cargoes. The distribution of cargo along the ship’s length has a direct influence on both the bending and shearing of the hull girder and on the stress in the localized hull structure.

The more commonly adopted cargo distributions are:

1.        Homogeneous hold loading condition.

2.        Alternate hold loading condition.

3.        Block hold loading condition.

4.        Part hold loading condition.

Homogeneous hold loading condition (Fully loaded)

This condition refers to the carriage of cargo, evenly distributed in all cargo holds as shown in figure 13. This type of cargo load distribution is, generally, permitted for all bulk carriers and is usually adopted for the carriage of light (low density) cargoes, such as coal and grain. However, high density cargoes such as iron ore may be carried homogeneously.

 

Hull10

Alternate hold loading conditions (Fully loaded)

Heavy cargo, such as iron ore, is often carried in alternate cargo holds on bulk carriers, as depicted in figure 14.

It is common for large bulk carriers to stow high density cargo in odd numbered holds with the remaining holds empty. This type of cargo distribution will raise the ship’s centre of gravity, which eases the ship’s rolling motion (ship rolling period is inversely proportional to the square root of GM and as the cargo is stowed up to more height in the holds, this raises the position of Centre of Gravity, G, thus reducing the value of distance GM, resulting in high rolling period, which in turn means comfortable rolling of the ship).

When high density cargo is stowed in alternate holds, the weight of cargo carried in each hold is approximately double that carried in a homogeneous load distribution.

To support the loading of the heavy cargo in the holds, the local structure needs to be specifically designed and reinforced (by adding extra frames in the holds). It is important to note that the holds which remain empty, with this type of cargo distribution, have not been reinforced for the carriage of heavy cargoes with a non-homogeneous distribution.

Ships not approved for the carriage of heavy cargoes in alternate holds by their classification society must not adopt this cargo load distribution.

 

Hull11

 

Block Hold loading and Part loaded Conditions

A Block hold loading condition refers to the stowage of cargo in a block of two or more adjoining cargo holds with the cargo holds adjacent to the block of loaded cargo holds being empty, as shown in figure 15.

This load distribution is adopted when the ship is partly loaded.

Part loaded and block hold loading conditions are not usually described in the ship’s loading manual unless they are specifically requested to be considered in the design of the ship.

When adopting a part loaded condition, to avoid over-stressing of the hull structure, careful consideration needs to be given to the amount of cargo carried in each cargo hold and the anticipated sailing draught.

 

hull12

When a ship is partly loaded, the cargo transported is less than the full cargo carrying capacity of the ship. Hence, the sailing draught of the ship is likely to be less than its maximum design draught.

The weight of cargo in each hold must be adequately supported by the buoyancy upthrust acting on the bottom shell. A reduction in the ship’s draught causes a reduction in the buoyancy upthrust on the bottom shell to counteract the downward force exerted by the cargo in the hold. Therefore, when a ship is partly loaded with a reduced draught, it may be necessary to reduce the amount of cargo carried in any hold.

To enable the cargoes to be carried in blocks, the cross deck and double bottom structure needs to be specially designed and reinforced.

Block loading results in higher stresses in the localized structure in way of the cross deck and double bottom structures and higher shear stress in the transverse bulkheads between the block loaded holds. The weight of cargo that can be carried in the block of cargo holds needs to be specially considered against the ship’s sailing draught and the capability of the structure.

In general, the cargo load that can be carried in blocks is much less than the sum of the full cargo capacity of individual holds at the maximum draught condition.

Part loaded and block hold loading conditions should only be adopted in either of the following situations:

1.        The loading distributions are described in the ship’s loading manual. In this case, the ship’s structure has been approved for the carriage of cargo in the specified loading condition and the loading conditions described in the ship’s loading manual should be adhered to, or,

2.        The ship is provided with a set of approved local loading criteria which define the maximum cargo weight limits as a function of ship’s mean draught for each cargo hold and block of cargo holds. In this case, it is necessary to ensure that the amount of cargo carried in each hold satisfies the cargo weight and draught limits specified by local loading criteria and the hull girder SWSF and SWBM values are within their permissible limits.

Shipboard Loading Guidance Information

 

Loading Manual

It is a statutory requirement of International Load line Convention (with some exemptions though) that, “ The Master of every new vessel be supplied with sufficient information, in an approved format, to enable him to arrange for the loading and ballasting of his ship in such a way as to avoid the creation of any unacceptable stresses in the ship’s structure.”

The ship’s approved loading manual is an essential onboard document for the planning of cargo stowage, loading and discharging operations. The manual describes:

1.        The loading conditions on which the design of the ship has been based, including permissible limits of still water shear force and bending moments.

2.        The results of calculations of SWSF & SWBM for each included loading conditions.

3.        The allowable local loading of the structure.

4.        Operational limits.

The ship’s loading manual is a ship specific document, the data contained therein is only applicable to the ship for which it has been approved.

Loading Instrument

Often called loadicator and in modern era of computers, it is more than often available in the form of Software, which can be run on any (designated, though) computer (of generic configuration) onboard the Ship.

This is an invaluable shipboard calculation tool which assists the ship’s cargo officer in:

1.        Planning and controlling cargo and ballasting operations.

2.        Rapidly calculating SWSF and SWBM for any load condition.

3.        Identifying the imposed structural limits which are not to be exceeded.

It is important to note that the loading Instrument is not a substitute for the ship’s loading manual. Therefore, the loading manual should also be referred when planning or controlling cargo operations.

 

Planning and control of Cargo Loading and Unloading operations on a Bulk Carrier

 

PREPERATION FOR CARGO OPERATIONS

1.        Cargo and Port Information

To make it possible to plan the cargo stowage, loading and unloading sequences, the ship should be provided with the following information well in advance, by the Shipper/Charterer/Cargo Terminal:

·         Cargo characteristics: stowage factor, angle of repose, amounts and special properties.

·         Cargo availability and any special requirements for the sequencing of cargo operations.

·         Characteristics of the loading or unloading equipment including numbers of loaders or unloaders to be used, their ranges of movement, and the terminal’s nominal and maximum loading and unloading rates, where applicable.

·         Minimum depth of water alongside the berth and in the fairway channels.

·         Water density at the berth.

·         Air draught restrictions at the berth & Channels.

·         Maximum sailing draught and minimum draught for safe maneuvering permitted by the port authority.

·         The amount of cargo remaining on the conveyor belt which will be loaded onboard the ship after a cargo stoppage signal has been given by the ship.

·         Terminal requirements/procedures for shifting ship.

·         Local port restrictions, for example bunkering and deballasting requirements, etc.

Cargo trimming is a mandatory requirement for some cargoes, especially where the risk of the cargo shifting or where liquefaction could take place.

The ship’s master should also be aware of the harmful effects of corrosive and high temperature cargoes and any special cargo transportation requirements.

Ship masters, deck officers, charterers and stevedores should be familiar with the relevant IMO Codes (for example, IMO Code of Safe Practice for Solid Bulk Cargoes, IMO Code of Practice for the Safe Loading and Unloading of Dry Bulk Carriers and SOLAS Convention)

2.        Making of a Cargo Stowage Plan and Loading/Unloading Plan

The amount and type of cargo to be transported and the intended voyage will have final say on the proposed departure cargo and/or ballast stowage plan.

The Chief Mate should always refer to the loading manual to ascertain an appropriate cargo load distribution, satisfying the imposed limits on structural loading.

There are two stages in the development of a safe plan for cargo loading or loading:

Stage 1: Given the intended voyage, the amount of cargo and/or water ballast to be carried and imposed structural and operational limits, make a plan for safe departure condition, known as Stowage Plan.

Stage 2: Given the arrival condition of the ship and knowing the departure condition (stowage plan) to be attained, make a safe loading or unloading plan that satisfies the imposed and operational limits.

In the event that the cargo needs to be distributed differently from the described in the ship’s loading manual, stress and displacement calculations are always to be carried out to ascertain, for any part of the intended voyage, so that :

·         The still water shear forces and bending moments along the ship’s length are within the permissible Seagoing limits.

·         If applicable, the weight of cargo in each hold, and, when block loading is adopted, the weights of cargo in two successive holds are within the allowable Seagoing limits for the draught of the Ship. These weights include the amount of water ballast carried in the hopper and double bottom tanks in way of the holds.

·         The load limit on the tanktop and other relevant limits, if applicable, on local loading are not exceeded.

The Consumption of Ship’s bunkers during the voyage should be taken into account when carrying out these stress and displacement calculations.

Whilst making a plan for cargo operations, the Chief Mate must consider ballasting operation to ensure:

·         Correct synchronization with cargo operation.

·         That the ballasting/deballasting rate is specially considered against the loading rate and the imposed structural and operational limits.

·         That the ballasting and deballasting of each pair of symmetrical port and starboard tanks is carried out simultaneously.

During the planning stage of cargo operations, stress and displacement calculations should be carried out at incremental steps commensurate with the number of pours and loading sequence of the proposed operation to ensure that:

·         The SWSF and SWBM along the ship’s length are within the permissible Harbour Limits.

·         If applicable, the weight of cargo in each hold, and when block loading is adopted, the weights of cargo in two adjacent holds are within the allowable Harbour limits for the draught of the ship. These weights include the amount of water ballast carried in the hopper and double bottom tanks in way of the holds.

·         The load limit on the tanktop and other relevant limits, if applicable, on local loading are not exceeded.

·         At the final departure condition, the SWSF and SWBM along the ship’s length are within the permissible Seagoing stress limits.

A cargo loading/unloading operation plan should be laid out in such a way that for each step of the cargo operation there is a clear indication of following:

·         The quantity of cargo and the corresponding hold numbers to be loaded/unloaded.

·         The amount of water ballast and the corresponding tank/hold number(s) to be discharged/loaded.

·         The ship’s draught and trim at the completion of each step in the cargo operation.

·         The calculated values of the still water shear forces and bending moments at the completion of each step in the cargo operation.

·         Estimated time for completion of each step in the cargo operation.

·         Assumed rate(s) of loading and unloading equipment.

·         Assumed ballasting rate(s).

The loading/unloading plan should indicate any allowances for cargo stoppage (which may be necessary to allow the ship to deballast when the loading rate is high), shifting ship, bunkering, draught checks and cargo trimming.

3.        Ship/shore Communication Prior to the commencement of Cargo operations

Effective means of communication are to be established between the ship’s deck officers and the cargo terminal which shall remain effective throughout the cargo operation. This communication link should establish:

·         An agreed procedure to STOP cargo operations.

·         Personnel responsible for terminal cargo operations.

·         The ship’s officer responsible for cargo loading/unloading plan and the officer in charge responsible for the on-deck cargo operation.

·         Confirmation of Information received in advance.

·         An agreed procedure for the terminal to provide the officer in charge with the loaded cargo weight, at frequent intervals and at the end of each pour.

·         An agreed procedure for draught checking.

·         The reporting of any damage to the ship from the cargo operations.

The ship’s officer responsible for cargo operation plan should submit the proposed loading/unloading plan to the cargo terminal at the earliest opportunity to allow sufficient time for any subsequent modifications and to enable the terminal to prepare accordingly. The ship’s officers should be familiar with the ISM’s Ship/Shore Safety Checklist.

4.        Before Commencing the Cargo operation

The cargo terminal should not commence any cargo operations until the loading/unloading plan and all relevant procedures have been agreed and the ship’s Master, where necessary, received a Certificate of Readiness issued by the respective maritime authorities.

 

MONITORING AND CONTROLLING CARGO OPERATION

1.        Monitoring of Stevedoring Operation 

The officer in charge has responsibility for the monitoring of the stevedoring operation and should ensure that:

·         The agreed loading/unloading sequence is being followed by the terminal.

·         Any damage to the ship is reported.

·         The cargo is loaded, where possible, symmetrically in each hold and, where necessary, trimmed.

·         Effective communication with the terminal is maintained.

·         The terminal staff advise of pour completions and movement of shore-side equipment in accordance with the agreed plan.

·         The loading rate does not increase beyond the agreed rate for the loading plan.

If there is likely to be a change by the terminal to either loading/unloading sequences or the Cargo loading/unloading rate, the officer in charge is to be informed with sufficient notice. Changes to the agreed loading/unloading plan are to be implemented with the mutual agreement of both the ship and terminal.

If a deviation from the agreed loading/unloading plan is observed, the officer in charge should advise the cargo terminal immediately so that necessary corrective actions are implemented without delay. If considered necessary, cargo and ballasting operations must stop.

2.        Monitoring the ship’s Loaded Condition 

The officer incharge should closely monitor the ship’s condition during cargo operations to ensure that if a significant deviation from the agreed loading/unloading plan is detected all cargo and ballast operation must STOP.

The officer incharge must ensure that:

·         The cargo operation and intended ballast procedure are synchronized.

·         Draught surveys are conducted at appropriate steps of the loading plan to verify the ship’s loading condition. The draught readings, usually taken at amidships and the fore and aft perpendiculars should be in good agreement with values calculated in the loading plan.

·         Ballast tanks are sounded to verify their contents and rate of ballasting/deballasting.

·         The cargo load is in agreement with the figures provided by the terminal.

·         The SWSF,SWBM and, where appropriate, hold cargo weight versus draught calculations are performed at intermediate stages of the cargo operation. These results should be logged, for recording purposes, against the appropriate position in the loading plan.

Following a deviation from the loading plan, the officer incharge should take all necessary corrective actions to:

·         Restore the ship to the original loading/unloading plan, if possible, or:

·         Replan the rest of the loading/unloading operation, ensuring that the stress and operational limits of the ship are not exceeded at any intermediate stages.

The modified loading/unloading plan should be agreed by both the officer responsible for the loading plan and the cargo terminal representative. Cargo operations should not resume until the officer in charge gives a clear indication to the terminal of his readiness to proceed with the cargo operation.

3.        Hull damage caused by cargo operations 

All damages should be reported to the ship’s Master. Where hull damage is identified, which may affect the integrity of the hull structure and the seaworthiness of the ship, the ship’s owner and the classification society must be informed.

A general inspection of cargo spaces, hatch covers and deck is always recommended to identify any physical damage of the hull structure.

 

Potential Problems which may happen during Cargo operations in a Bulk Carrier

1.        Deviation from the limitations given in the approved loading Manual

Exceeding the permissible limits specified in the ship’s approved loading manual will lead to over-stressing of the ship’s structure and may result in catastrophic failure of hull structure. When deviating from the cargo load conditions contained in the ship’s approved loading manual, it is necessary to ensure that both the global and local structural limits are not exceeded. It is important to be aware that over-stressing of local structural members can occur even when the hull girder still water shear forces (SWSF) and bending moments (SWBM) are within their permissible limits.

Exceeding the maximum permissible cargo load in any hold will lead will lead to over-stressing of local structure. Over-stressing of the local structure will occur when:-

·         The weight of cargo loaded into a hold exceeds the maximum permissible value specified at full draught.

·         The weight of cargo loaded into adjacent holds exceeds the maximum combined value at full or reduced draught.

Overstressing of the local structure may also occur when the weight of cargo loaded into an individual hold has sufficient support of upward buoyancy force; this circumstance can occur when cargo is transported by the ship in a shallow draught condition (for example, partial load condition with some holds full and remaining holds empty)

2.        Loading Cargo in a Shallow draught condition 

To minimize the risks of over-stressing the local structure, the largest possible number of non-successive should be used for each cargo hold.

Loading cargo in shallow draught condition can impose high stresses in the double bottom, cross deck and transverse bulkhead structures if the cargo in the hold is not adequately supported by the buoyancy upthrust. If applicable, the cargo weight limits for each cargo hold, and two adjacent cargo holds, as a function of draught, (the local loading criteria) are not to be exceeded.

3.        High Cargo loading rates in the Bulker. 

High loading rates may cause significant overloading within a very short space of time. The officer incharge should be prepared to STOP cargo operations if the loading operation deviates from the agreed loading plan.

There are three main problems associated with high loading rates which may result in over-stressing the ship’s structure, namely:-

·         The sensitivity of global (overall) hull girder SWSF and SWBM. To illustrate the point, see the example below

·         Overloading the local structure.

·         Synchronization of the ballasting operations.

EXAMPLE OF THE SENSITIVITY OF THE HULL GIRDER TO CARGO DISTRIBUTION OF A BULK CARRIER WITH 7 HOLDS

 As shown in table below, the inadvertent loading of 900 tones into each of the holds numbered 1 and 7 took 5.4 minutes if two loaders were in operation. The re-distribution of cargo causes SWSF and SWBM to exceed the allowable limits by 17 and 33 percent respectively.

Loading Condition

Hold 1 (tones)

see note 1 

Hold 3 (tones)

Hold 5 (tones)

Hold7 (tones)

Maximum SWSF (tones)

Maximum SWBM (tones-m)

Approved ore load condition

16000

18000

18000

16000

4900

(97%)

144700

(99%)

10% of No.5 hold evenly loaded to holds 1&7

16900

(5.4 minutes)

18000

16200

16900

(5.4 mins)

5900

(117%)

193500

(133%)

 

Notes:

1.        The time taken to load the additional cargo is presented in the brackets under the respective hold cargo weight, assuming a loading rate of 10000 tone/hour.

2.        Figures in the bracket in SWSF and SWBM columns are the respective percentages of permissible.

High cargo loading rates may create problems with the ballasting operation as the pumping capacity of the ship may be relatively low compared to cargo loading rate. In such cases the cargo operation must be stopped to ensure synchronization with the ballasting operation is maintained. When necessary, the loading rate must be adjusted to synchronize with the ship’s pumping capacity.

 

4.  Asymmetric Cargo and Ballast Distribution

It is recommended that high density cargo be stowed uniformly over the cargo spaces and trimming be applied to level the cargo, as far as practicable, to minimize the risk of damage to the hull structure and cargo shift in heavy weather.

The distribution of cargo in a hold, and water ballast distribution, have an important influence on the resultant stress in the hull structure. The double bottom and cross deck structure are designed based upon a trimmed cargo distributed symmetrically in a hold space.

Still water shear forces and bending moments given in the ship’s loading manual and the corresponding calculations from onboard loading instruments are based on an even distribution of cargo in a hold space, unless otherwise indicated.

Still water shear force and bending moments calculated with an onboard loading instrument do not consider the torsional loads acting on the hull girder resulting from asymmetrical cargo or ballasting loading.

When heavy cargo is poured into a cargo space at one end of the cargo hold, the lateral cargo pressure acting on the transverse bulkhead, as a result of the cargo piling up at one end of the space, as depicted in figure 16, will increase the loads carried by the transverse bulkhead structure and the magnitude of transverse compressive stresses in the cross deck.

 

hull13

 

When the same loading pattern is also adopted for the adjacent cargo hold , as shown in figure 17, the lateral cargo pressure acting on the transverse bulkhead will be largely cancel out. However, in this case, a large proportion of the vertical forces on the double bottom are transferred to the bulkhead between the two loaded holds which could lead to shear buckling of the transverse bulkhead structure, compression buckling of cross deck and increased SWBM in way of the transverse bulkhead. Cargo should always be stowed symmetrically in the longitudinal direction, and trimmed, as far as practical.

 

hull14

 

Stowing cargo symmetrically about the ship’s centre line in a cargo space, as depicted in figure 18, induces torsional loads into the structure which causes twisting of the hull girder. When the hull girder is subjected to torsion, warping of the hull section occurs which gives rise to shearing and bending of the cross deck structure.

 

hull15

 

Water ballast should always be carried out symmetrically in port and starboard tanks with equal levels of filling, the final level of all water ballast tanks and holds must satisfy the requirements specified in the ship’s approved loading manual to avoid damage to the internal structure due to sloshing effects.

The ballasting and deballasting of port and starboard ballast tanks should be carried out simultaneously, so that the amount of water ballast in each corresponding pair of port and starboard ballast tanks remains the same throughout ballasting or deballasting operations, as depicted in figure 19 and 20. Asymmetrical distribution of water ballast induces torsional loads, causing twisting of the hull girder. 

 

hull16

 

Torsional loading of the hull girder is considered to be an important contributory factor to recurring cracking at the hatch corners and to problems associated with hatch cover alignment and fittings. In extreme cases, this can lead to extensive buckling of the cross deck structure between the hatch openings.

5. Lack of effective Ship/Shore communication

The lack of effective ship/shore communication may increase the risk of inadvertent overloading of the ship’s structure. It is important that there is an agreed procedure between the ship’s officers and terminal operators to STOP cargo operations. The communication link established between the ship and the terminal should be maintained throughout the cargo operation.

6. Exceeding the Assigned load line marks

 All ships engaged on international voyages are assigned with load line marks in accordance with the provisions of the International Load Line Convention 1966.

The appropriate lines marked on the ship’s side shall not be submerged at any time during the seagoing voyage.

 To allow for the difference between the dock water density and the sea water density, the ship may be loaded beyond the appropriate mark by the dock water allowance. The dock water allowance is only applicable in a port environment. It is a statutory requirement that the ship is not to be loaded beyond the limits specified in the Load line Certificate.

The practice of inducing a hogging deflection to the hull girder by the end holds trimming to maximize the cargo carrying capacity of the ship to the appropriate marks is to be avoided as this may result in the over-loading of the end holds beyond the allowable limit and an increase in both overall and local stresses.

 7. Partially filled Ballast Holds or Tanks

Sailing with partially ballast holds is prohibited unless the approved loading manual approves of such a practice. Cargo holds designed for partially filled in harbour for the purpose of reducing the ship’s air draught are not to contain any water ballast while at sea.

 Where ballast holds, and in some instances ballast tanks, are partially filled, there is likelihood of sloshing. Sloshing is the violent movement of the fluid’s surface in partially filled tanks or holds resulting from ship’s motions in a seaway.

Sloshing will result in the magnification of dynamic internal pressures acting on the Hold/Tank boundaries. For any tank design, dimensions, internal stiffening and filling level, a natural period (frequency) of the fluid exists, which, if excited by the ship’s motions, can result in very high pressure magnification (resonance) which can result in damage to the tank/hold’s internal structure.

 To minimize the effects of sloshing, the liquid’s motion needs to be controlled by ensuring that tanks are either pressed up or empty (sloshing can occur at low filling levels).

 

 

Hits: 2267
0

Shipping industry professional may think they hear the sound of new regulations as they are slammed onto their desks. What is then all the noise concerning noise at IMO? This may very

well be the question from ship owners, operators and builders closely following activities at the International Maritime Organization (IMO).

In 2013, IMO issued mandatory regulations for shipboard airborne noise and earlier in 2014 IMO

internal committees approved new draft guidelines for minimizing underwater noise.

Airborne Noise

Since 1981, the IMO has established a guideline for shipboard airborne noise (IMO Resolution A468XII-1981). This guideline included information on sound measurement, acoustic insulation, hearing protection and maximum recommended sound pressure levels by ship compartment type.

As noted in the resolution, its purpose was to reduce mariner exposure from noise in order to provide a safe working environment (i.e. ability to hear audible alarms), reduce noise-induced hearing loss (NIHL) and provide an acceptable degree of comfort for the passengers and crew on the ship.

Many vessels were designed and built to these guidelines enforced only through the contract between the ship owner and the shipbuilder.

In July 2007, all of the European Union (EU) member states and the European Commission (EC) collectively made the proposal to update the 1981 guidelines with the goal making them mandatory. This occurred under the framework of the 83rd Session of the Maritime Safety Committee (MSC) at the IMO headquarters in London.

The reason for making the current IMO guide mandatory was to address a gap in the Safety

of Life at Sea (SOLAS) Regulation II-1/36 which “requires that measures be taken to reduce noise in machinery spaces to acceptable levels.” As noted in the meeting minutes, “the SOLAS Regulation did not defi ne “acceptable levels,” but only provided a reference to the old IMO guideline, A.468.”

The MSC “work program” was approved and A.468 was given to the Subcommittee on Ship Design & Equipment (DE) Committee of IMO for the detailed review and revision. The work of revising the noise code started at the 53rd DE meeting and progressed through the 56th DE meeting concluding in February 2012. Final approval was granted at 91st meeting of the MSC in November 2012.

This new SOLAS regulation (Chapter II-1/3-12; “Protection against noise” & “Code on noise levels on board ships”) requires applicable vessels to be constructed in such a manner that certain types of compartments will have noise levels no higher than specified in the Code.

The new Code has mandatory and recommended sections, but the majority of the regulation

is required. The Code is only mandatory for ships that are 1,600 gross tons (GT) or larger and for which the building contract was placed on or after July 1, 2014.

The new code will not be applicable to numerous types of vessels such as: dynamically supported craft, high-speed craft, fishing vessels, pipe-laying barges, crane barges, mobile offshore drilling

units, pleasure yachts not engaged in trade, naval ships, troopships, ships not propelled by mechanical means, pile driving vessels and dredgers.

An abbreviated list of the noise level limits is given in Table 1 along with the limits which were part of the old A468 code.

b2ap3_thumbnail_noise.jpg

What’s new in the Noise Code?

For the most part, not much has changed from the old to the new noise limits. The only change from the old to the new (1,600 to 10,000 GT) is a decrease for non-specified work spaces.

The limit used to be 90 dB(A) and it was reduced to 85 dB(A). The new code further divided the noise limits between less than 10,000 gross tons and greater than 10,000 gross tons.

Also in the new Code a couple of room types had 5 dB lower limits for ships that were 10,000 gross tons or larger.

The lower limit was put in place due to fact that it is easier to achieve lower limits on physically larger ships.

One need not be apprehensive of the noise limits specified in the new IMO code for ships of 1600 GT and up. These compartment noise limits can be achieved with what have become standard noise control treatments which can be designed into the ship for only a very small percent increase in the total ship acquisition cost.

The key to meeting any shipboard noise requirement is to make sure the noise requirements are part of the design process when the ship is built and a good way to make sure the noise limits are achieved is to require a noise evaluation before construction starts. It has been found that dealing with noise requirements after construction can increase the cost by a factor of ten to twenty.

Shipping Industry appears to have received the new noise regulation positively, at least according to Kathy Metcalf the Director of Maritime Affairs at the Chamber of Shipping of America (CSA). She stated that, “The industry has been aware of the process during the development of the airborne noise regulations. The industry in general saw these developments as necessary since they related to the health of the crew on board the vessel and were generally supportive of these developments as

they apply to new vessels. Industry concerns related to how or if it would be possible to comply with the requirements for existing ships…is still ongoing.”

Underwater Noise

Just a little after IMO decided to update “Code on Noise Levels On Board Ships,” a proposal was presented by the United States to address noise below the waterline.

The lead on this action was taken by U.S. National Oceanic and Atmospheric Administration (NOAA).

There was vigorous non-governmental organization (NGO) and international participation in the development of the guide especially from the EU nations.

The motivation for introducing the topic of mitigation of underwater noise was the hallmark 2008 conference held in Hamburg. It was sponsored by the Darmstadt, Germany-based Okeanos Foundation for the Sea and brought together experts in mitigation, measurement and effect of anthropogenic (manmade) noise on marine animals and fi sh.

The final report from the Okeanos conference called for a reduction of unintentional ship noise of 3 dB over the next ten years and 10 dB over the next 30 years.

The underwater noise guidelines are not yet offi cially published by IMO and are assumed to be released in the near future and under the current title, “Guidelines for the Reduction of Underwater Noise from Commercial Shipping.”

There still is an open question within IMO whether the guideline’s title should be revised to include reference to adverse impact of marine life. The body of the guideline is relatively solidified with a draft approved by the IMO’s Design & Equipment (DE) Committee in 2013 and the Marine Environment Protection Committee (MEPC) in March 2014.

The guideline’s Preamble notes that “Concern has been raised that a significant portion of the underwater noise generated by human activity may be related to commercial shipping.” It goes

on to note that international (scientific) community recognizes such sound may have both short-term and long-term negative effects on marine mammals and other aquatic life. The proposed guidelines were specifically developed to be applicable to any commercial ship, yet exclude any naval ship or vessel that deliberately puts sound into the ocean, such as seismic or sonar systems used in oil and gas exploration.

As noted in the guide, the purpose of the non-mandatory guidelines is to provide general design advice with respect to the mitigation of vessel generated underwater noise. The guidance is mostly aimed at ship designers, shipbuilders and ship owners.

The guide’s primary focus is on the main sources of underwater noise generated by propellers and onboard machinery. It also mentions that hull form and operational aspects can be factors as well. Much, if not most, of the underwater noise is caused by propeller cavitation, but onboard machinery and operational modification issues are also relevant.

The optimal underwater noise mitigation strategy for any ship should at least consider all relevant issues above.

These Guidelines consider common technologies and measures that may be relevant for most sectors of the commercial shipping industry. Designers, shipbuilders, and ship operators

are encouraged to also consider technologies and operational measures not included in these Guidelines, which may be more appropriate for specific applications.

The draft guideline contains more detailed information regarding prediction of underwater noise, underwater noise measurement standards, ship design considerations, and treatment of on board machinery, additional technologies, operational factors and maintenance considerations. Most importantly, industry should be relieved that the draft guideline does not provide any numerical noise limits at this time.

Both the new airborne noise regulation and the draft underwater noise guideline are available from the IMO website.

Hits: 4589
0

Maritime transport is an important factor of economic development of every maritime country. Its basic task is providing shipping services, meaning that they may as well be considered as the product of the shipping economic activity.

Regarding the current international shipping crisis, the key to success of every shipping organization, region and maritime country lies in efficiency and safety of its maritime shipping services – on one hand, and on the other hand, is about having an integrated conceptual approach as regards the key elements i.e. goods, ships and ports.

It is the aim of this blog to broadly emphasize the particularities of each key element contributing.

The fundamental aim of the maritime transport and trade is to ensure the domestic and international regular and safe circuit of goods, in coordination with economic efficiency and according to the conventions, laws and contract terms in force. The transport is an element indispensable to life because it offers people the possibility to know, perceive and assimilate, as easy as possible, what human
civilization and culture have to offer. The existence and improvement of means of transportation have allowed contact between various countries and nations, which has determined the economical, political and cultural life of mankind.


The maritime transport contributes to the closeness of geographical areas, development of economic branches and territorial distribution of production and marketing. The level of development of maritime transport has a direct impact on the social division of labor, which, in its turn, determins the specialization, as well as the increase of the degree of accessibility to natural resources and fruits of human labor.

The basic elements as indispensible to the achievement of the fundamental aim of transport are the following:

  • Goods - as object of maritime transport;
  • Ships - as maritime means of goods transportation;
  • Ports - as flow nodes, transshipment and warehousing of goods.

GOODS | SHIPS | PORTS AS KEY ELEMENTS OF MARITIME TRANSPORT

Goods - as objects of the maritime transport

It is obvious that, in the development of maritime transport by its three basic elements, the goods have an essential role, both for the ports development and evolution of ships. All three elements are permanently interdependent,however the research performed in the past has indicated that the main element in the economy of maritime transport is, either as raw material, by traffic diversity, quantity and regularity or as manufactured products, the more diverse, complex and demanded they are in international trade, the more economic, scientific and technical progress is advanced.

Advanced technologies had an influence on the ports, which expanded in recent years and modernized in order to allow the profitable handling of goods. At the same time, at the request of owners, the innovative processes have made the transition from the classic freighter to specialized vessels, which incorporate state of-the-art technologies, subsequent to the changes occured on the freight markets, imposed by the quality and quantity evolution of goods in maritime traffic.


It is worth to mention that the propelling element of maritime transport is the quality-quantity leap of the goods factor, the other two, ships and ports, being the effects which, in their turn, influence the cause, forming the dialectic deterministic chain. Considering the opinions expressed in the specialized literature, we may claim that the goods influence the development of ships and ports through their physical condition, quantity and regularity on various transport routes; quality, diversity and handling and stacking characteristics; nuisance value; sensitivity; perishability and specific freight by each type of goods.

According to their physical condition and handling and stacking characteristics, the goods subjected to maritime transport can be classified into two large categories:

  • Bulk cargo (or continuous goods), including homogenous lots of unpacked goods, large enough to cover themselves the transport capacity of a ship or of a cargo hold, which allow a continuous or nearly continuous loading flow;
  • General cargo (or discrete goods) which, by its nature, consists of non-homogenous lots of packed goods, smaller in size, which does not allow a continuous flow of loading and requires special means of packing, loading, stacking, lashing, transshipping and unloading;

The impact of each category of goods on the evolution of ports and ships for the purpose of obtaining benefits can be emphasized by the following two aspects:

  1. Due to the possibilities of continuous handling operations, the bulk carriers (oil tankers, dry bulk carriers, bulk carriers, etc), equipped with modern technology represent the most profitable and widely used segment of the maritime transport;
  2. General cargo ships which are not equipped with modern handling technologies are less profitable and consequently, their use is not remarkably beneficial. The ideal solution for the cost effectiveness of general cargo transport under the current development circumstances is to perform a continuous loading flow for this category of goods, as well.

The quantity of goods and the regularity of their flow involve the use of ships on certain routes, according to the transport system- by liner or tramps. Depending on the features of goods (quality,diversity, handling and stacking characteristics, degree of peril, sensitivity and perishability), important easements are determined both in loading and unloading ports and onboard ships, requiring the fitting with specific machineries, as necessary for handling goods in order to maintain their quality and quantity integrity.

The freight is set depending on certain factors, such as: class and tonnage of vessel, distance between ports,season, special expenditures, volume of shipped goods,kind of goods and their nuisance value. Freight value is different depending on the range of shipped goods, which proves the influence of cargo on ships cost effectiveness through the transport price.

Requirements for ships used in goods transportation

Experience has shown that there is a close connection between the basic elements of maritime transport that is between ships, goods and ports; if one of those components would lag behind, the cost
effectiveness of the whole system would be deeply and shortly affected.

Along with the diversification of goods and increased demand for raw materials and manufactured goods transportation, the diversification and specialization of ships as regards their transport capacity, fitting with modern mechanization and automation,installations intended to goods handling and transshipment became necessary.

This period is characterized by the expansion and modernization of ports, roads and port basins for the access of large and modern ships, as well as of the operation front by raising quays, equipping ships with high flow installations by building specialized berths, by the modernization of maritime port terminals and management of the port area as judiciously as possible.

Returning to the ships, it is worth mentioning that they are highly complex technical constructions and extremely expensive investments. Therefore, they must fulfill two categories of
essential conditions:

a) Technical-constructive conditions intended to provide the ship's strength to exceptional environment stress within the shipping area consisting with her class and set forth by the class certificate. Compliance with such requirements mainly guarantees the safety of the ship and, implicitly, of the goods onboard, as well as of her personnel, providing her seaworthiness – a personal obligation of the owner and an implicit prerequisite for the ship before each voyage. Among the technical progresses, the following may be mentioned:

  • building of metal hulls for ships driven by steam engines;
  • replacement of steam engines with diesel engines;
  • passing from hull's rivetting to welding;
  • emergence of modern systemsof shaft closing,loading installations and navigationequipments;
  • introduction of various automation technologies which allow selfloading of ships and computer assisted navigation;
  • computer assisted design, which reduced thequantity of metal used in shipbuilding by 30%, and increase of naval paint quality, which has reduced corrosion and resistance to advancing due to frictions;

b) Technical-economical and cost effectiveness conditions representing the total constructive and operational characteristics, as regards the performance which must ensure the efficiency of each ship, maritime transport organization and generally, of the company, all such leading to profit making.

The above ship-related conditions may be fulfilled by encompassing the following aspects:

  •  adequate space, appropriate facilities and profficient installations for rapid stacking,preserving and handling of goods, depending on to the type and destination of the ship;
  • ensuring the best possible deadweight coefficient;
  • consumption and overhead costs as low as possible, both during laying and operation of the ship;
  • high speed to ensure an increased number of travellers each year.

Both technical-constructive and technical-economic conditions may be fulfilled by several factors. Naval research and design institutes and shipyards are in charge with the technical design and building of ships, while shipping companies and charterers concerned in rational and proficient exploitation of ships are responsible for organization and management matters.

Currently, the following categories of ships are intended to maritime transport of goods:

  • General cargo ships;
  • Bulk cargo ships;
  • Oil and chemical tankers;
  • Container carrier ships;
  • RO-RO and vehicle carriers;
  • Reefer ships.

Importance of ports, as flow nodes, transshipment and warehousing of goods

In the opinion of maritime transport experts, the modern maritime commercial port is a specially arranged seashore area where maritime and land transport ways of the continental area serving the port are joined and where there is a continuous and organized two-way trade in goods.

Initially, the ports were defined as simple places where goods were loaded or unloaded. In the course of time, they have evolved from the status of simple interface between maritime and land transport (first generation ports), to the current phase of industrial and commercial clusters where several services are rendered (third generation ports).

Thus, we reach the concept of logistic for value adding, which means that besides the primary loading or unloading functions, the ports add value to the goods.

Just in order to respond to this new aspiration, ports are currently designed and developed as close as possible to the place of manufacturing and distribution of goods, within a wide area.

Taking into account the opinions expressed in the specialized literature we can state that ports, regardless of their size, have three important functions: transshipment, storage and industry.

The function of transshipment in very important and refers to the transfer of goods from ships to shore and back, in order to provide optimal conditions for the goods flow, as from the shipper to the consignee.

Improvement of such function depends on the following:

  •  increase in operation speed and introduction of the continuous flow of goods handling;
  • reduction of the laying time, thuis leading to a decrease in the transshipment time;
  • modernization of maritime terminals, fitting them with modern handling installations and means of partial and total processing of raw materials;
  • efficiency of infrastructure (piers, basins and quays), as well as overstructure works, represented by means of transshipment placed alongside the berthing area, considering that the transshipment takes place in the port basin, on quays or operating berths;
  • performing an active cooperation between ship and quay.

The port function of transshipment has two forms of manifestation: transitional storage and warehousing storage. The transitional storage refers to the situation when stocks are formed in order to decrease the gap between the large capacity of modern ships and the means of land transportation.

The warehousing storage has a strong economical character and here we have several situations:

  • balancing warehousing, due to the seasonal supplying in comparison to the permanent consumption flow;
  • warehousing as a result of an order, for the purpose of accumulating savings;
  • commercial warehousing, representing a measure of precaution against worldwide price fluctuation phenomenon;
  • warehousing throughout the processing, for goods requiring maturity before processing.

The industrial function refers to the connections between large ports by inland waterways, in order to cluster heavy industry enterprises in their proximity. On the other hand, there is a tendency for modern ports development by expansion, deepening, new locks, canals and development of waterways inside the continent for ships of various types, in order to avoid large crowded ports.

However, port efficiency should be seen as a set of interrelated issues such as architecture and aquarium construction, the size of ships and cargo traffic, major operating berths, safety operation of vessels and port economic development priorities in the current requirements the seaports.

SYSTEMATIC ASPECT OF MARITIME TRANSPORTATION

The era of rapid economic and technicaltechnological development of modern production requires a well-organized and above all, a safe transport system. The study of traffic as a whole involves the study of individual types and systems, especially of its most important part: maritime transport system.

Maritime transport, therefore, involves transport of passengers and/or goods by sea, which is often called shipping trade (seaborne), which can be passenger and cargo shipping.

Theoretically speaking, cargo shipping is a very broad term assuming various modes of employment of cargo ships, so there are a few types accordingly - tramp, liner and specialized shipping.

Each of these types of cargo shipping operates in accordance with their operational processes and control procedures, which are managed and controlled by quality management of shipping companies, and supervised by the competent state institutions and international organizations for control of maritime navigation.

Maritime transport involves the physical transport of cargoes from an area of supply to an area of demand for certain types of goods, together with all the activities required to support and facilitate such transport.

Maritime transport system includes three essential components important for the movement of goods, and they are as follows:

  • fixed infrastructure such as ports or terminals;
  • means of transportation such as ships and barges;
  • organizational system necessary to ensure that ships and fixed infrastructure are used effectively and efficiently

However, the realization of shipping services involves a number of commercial activities, the existence of appropriate infrastructure, procedures for shipping operations, organizational management systems
such as enterprise resource planning or information system which integrates all operations and applications within a shipping company or organization.

The efficiency of shipping services is determined by the ratio of supply and demand on the shipping market, and managerial maritime transport uses market mechanisms in the regulations of supply and demand relationship.

As a first conclusion, modern maritime ports have simultaneosly the following functions: transit gate towards maritime and land ways and maritime terminal, as organizational unit of transit improvement, as well as regional processing of mass-produced goods.


As a second conclusion, it can be stated that the maritime transport is a highly complex economic activity of national and international interest, which must be considered and developped in such a way that to administer the needs and to ensure profitability.

The main function of maritime transport is to ensure the link between production and consumption and is characterized by two essential economic features:

  • economic profficiency to the sense of complying with defined requirements;
  • profitability, as essential prerequisite of a wide economic activity, which involves transport costs and transport-related operations costs.
Hits: 1257
0

                             

This blog  focuses on the implementation of fuel cells in marine systems as a propulsion system and energy source. The objective is to provide an overview of the pertinent technical and  legislative issues for marine applications of fuel cells.

What is Fuel Cell | Introduction and its advantages

Fuel cells are electrochemical devices that directly produce electricity from chemical energy of a fuel .

The fuel cell’s operating principle was discovered by Sir William Grove in 1839, although it is also said that a Swiss scientist Christian F. Shoenbein independently discovered the very same effect at about the same time.

Inside the fuel cell an oxygen reaction reduction occurs between hydrogen and oxygen giving rise to water and heat. The electrons released in the reaction are driven by an external circuit producing electricity.

Then, fuel cells are in some aspects similar to batteries. They have an electrolyte, a cathode and a anode, and generate direct current electricity through electrochemical reactions. However, unlike batteries, fuel cells require a constant supply of fuel and oxidant. Typically hydrogen is used as fuel.

Pure hydrogen, present in a mixture of gases or directly hydrocarbons such as methane or natural gas for example, could be used. Oxidant is pure oxygen or air.

Only if a fuel cell works with pure hydrogen as a fuel, water and heat are the unique products. That means they are cleaner than conventional generators, in which, for example, carbon dioxide is always an exhaust gas. Moreover, typical conventional generator’s efficiency is about 15-20%, whereas the efficiency of a fuel cell is about 30-40% or even more than 70% when cogeneration is used.

This higher efficiency is due to energy conversion, contrary to that occurs in conventional generators, is done in a single step without burning neither involving any moving parts. Therefore fuel cells can be more efficient, quieter, with less maintenance and more durability.

It is known that the global energy availability and sustainable development is a big challenge and big efforts have to be undertaken in all energy consumption sectors and this technology, characterized by particularly high electrical efficiencies and low emissions, would help to reduce carbon dioxide emissions.

Construction of a Fuel cell

Normally fuel cells produce low voltages and they must be assembled into a fuel cell stack to reach the power required in usual applications. Then, fuel cells are by their nature, modular devices and their power can go from microwatts to megawatts, which makes them useful in a variety of applications: automotive, marine, naval, space or stationary electricity generation have already been dated but also portable applications are possible.

A fuel cell stack is constituted by:

Bipolar plates: they are electrical conductive parts which put in contact the anode of one cell with the cathode of the next cell. The first cell and the last one have end plates instead bipolar plates, and they are in contact with the current collectors. They are usually made of stainless steel or graphite.

Mass flow channels: they are ducts inside which fuel and oxidizer flow. Their walls are the bipolar plates.

Gas diffusions layers: are porous media situated between the bipolar plate and the catalyst layer.

Catalyst layers: they are the zones where the electrochemical reactions take place.

Electrolyte: it is a substance which carries electrically charged particles from one electrode to the other of the same cell.

• Another parts of a fuel cell are seals, current collectors or some interconnectors.

In the case of a single fuel cell, the most common constituents, shown in the Figure below, are almost the same of a fuel cell stack. In this figure Schematic representation of a single fuel cell with indication of its main components is shown and the flows corresponding to the different fuel cell types attending to the electrolyte used are represented.

b2ap3_thumbnail_BLOG-FOR-SAILORS-CLUB-image-1.png

Types of Fuel Cells and how does electron-proton flows inside the Fuel cell

There are several types of fuel cells, but in a general way they can be divided into two general groups, those having an acid electrolyte and those having an alkaline one.

If the electrolyte has acid behavior, the protons travel across of it, and if not, there are the negative ions which cross the electrolyte.

The processes taking place inside a fuel cell with acid electrolyte begin with hydrogen flowing through the anode channels, as well as oxygen through the cathode channels; the flows are addressed to the gas diffusion layers.

When they reach the catalyst layers, electrochemical reactions, including all the intermediary steps, happen. Then, proton transport through proton-conductive electrolyte occurs from the anode to the cathode.

Meanwhile electrons are driven through electrically conductive cell components to the external circuit and return to the fuel by the cathode side, where react with oxygen and protons to produce water and heat.

So, the electrochemical reactions in a hydrogen fuel cell happen simultaneously on both sides of the electrolyte, the anode and the cathode.

The basic fuel cell reactions are:

At the anode: H2 = 2H+ + 2e-

At the cathode: 1/2 O2 + 2H+ + 2e- = H2O

Overall: H2 + 1/2 O2 = H2O

The most usual classification of fuel cells is made attending to the type of electrolyte they use. These types are summarized in Figure as depicted above and described below:

• Alkaline fuel cells (AFC) use KOH as the electrolyte. Operation temperatures go from less than 120ºC to 250°C. They have been used in the space program (Apollo and Space Shuttle) since the 1960s.

• Polymer electrolyte membrane or proton exchange membrane fuel cells (PEM), use a thin proton conductive polymer membrane as the electrolyte, typically a perfluorosulfonated acid polymer with operating temperatures between 60 and 80°C, or an acid doped polybenzimidazole for temperatures above 120ºC (HTPEM). PEM fuel cells are a promise for automotive applications, but can also be used for small-scale distributed stationary power generation, and for portable power applications. There is a type of PEM directly fed with methanol which is called direct methanol fuel cell (DMFC).

• Phosphoric acid fuel cells (PAFC) use concentrated phosphoric acid as electrolyte. Usually a SiC matrix is used to retain the acid. Operating temperatures are between 150 and 220°C. Hundreds of 200 kW PAFC units have been installed all over the world for stationary electricity generation.

• Molten carbonate fuel cells (MCFC) have the electrolyte composed by a combination of alkali (Li, Na, K) carbonates in a ceramic matrix. Operating temperatures lie between 600 and 700°C where the carbonates form molten salt with high conductivity. These fuel cells are suitable for stationary power generation applications.

• Solid oxide fuel cells (SOFC) use a solid electrolyte, usually Y203-stabilized ZrOi (YSZ). The operating temperatures are the higest of all the fuel cells, from 800 to 1000°C. These fuel cells are also for stationary power generation applications, although smaller units are being developed for auxiliary power and portable power units.

There is also a hybrid between fuel cell and battery known as semi-fuel cell because one of the electrodes, the anode, is solid, made of aluminium (Al), and no feeding is necessary, whereas hydrogen peroxide (HP) is continuously added to maintain the oxidant concentration in the alkaline electrolyte.

Reaction equations are as follows :

At the anode: Al + 4OH- = Al(OH)4- + 3e-

At the cathode: H2O2 + 2e- = 2OH-

Overall: 2Al + 3H2O2 + 2OH- = 2 Al(OH)4- + 6e-

Present and Future of Fuel Cells

At present costs, large-scale use of fuel cells is not competitive. Difficult, but achievable advances could change this. The fuel cell is not a comprehensively disruptive technology; it can be seen as a replacement for conventional power trains, generators or batteries.

One of the characteristics of fuel cell systems is that their efficiency is nearly unaffected by size. This means that small, relatively high efficient power plants can be developed, thus avoiding the higher cost exposure associated with large plant development.

As a result, initial stationary plant development has been focused on several hundred kW to low MW capacity plants. Smaller plants (several hundred kW to 1 or 2 MW) can be sited at the user’s facility and are suited for cogeneration operation, that is, the plants produce electricity and thermal energy (combined heat and power CHP).

Larger, dispersed plants (1 to 10 MW) are likely to be used for dispersed electric-only use. The plants are fuelled primarily with natural gas. Once these plants are commercialized and price improvements materialize, fuel cells will be considered for large base-load plants because of their high efficiency.

Since the late 1980s, there has been a strong push to develop fuel cells for use in light duty and heavy-duty vehicle propulsion. A major drive for this development is the need for clean, efficient cars, trucks, and buses that can operate on conventional fuels (gasoline, diesel), as well as renewable and alternative fuels (hydrogen, methanol, ethanol, natural gas, and other hydrocarbons).

With hydrogen as the on-board fuel, such vehicles would be zero emission vehicles. With on-board fuels other than hydrogen, the fuel cell systems would use an appropriate fuel processor to convert the fuel to hydrogen, yielding vehicle power trains with very low emissions and high efficiencies.

Further, such vehicles offer the advantages of electric drive and low maintenance because of the few critical moving parts.

It is estimated that in about 30 years, the fleets of developed countries (currently over 750 million units, including cars, buses and trucks) will have more vehicles with an electric motor powered by fuel cells than powered by internal combustion engines.

However, currently the main problem in driving this technology in the transport sector is the high cost of manufacturing, fuel quality and size of the unit. The research in this area seems to have opted to use methanol as a fuel source and use oxygen from the air. This could eliminate the fuel reforming process.

Because of the modular nature of fuel cells, they are attractive for use in small portable units; the continued development of fuel cells has contributed to the development of many mobile electronic devices. The miniaturization of fuel cells offers serious advantages over conventional batteries, such as increased operating time, reduced weight and ease of reloading.

When portable fuel cell systems are discussed in public, what often springs to mind first are applications where fuel cells compete with batteries. Well-known examples are cellular phones, laptop computers, camcorders, and similar electronic devices. For these applications, the following parameters to be given on the batteries will be necessary to consider:

• Low temperature operation.

• Availability of fuel.

• Quick Activation.

Whether these applications will be successful or not depends on several considerations, including if:

• Fuel cell systems can win the race against advanced battery technology such as lithium ion secondary batteries.

• They can be made small enough to fit inside portable electronic devices.

• The price is attractive enough.

• The fuelling problem can be solved.

The fuelling problem means that replacement fuel cartridges or similar devices must be readily available and must be more convenient to handle than, say, second batteries pack for a laptop computer.

Also, the overall fuelling process must have clear advantages over recharging from a power socket, which is now readily available almost everywhere.

Another consideration is safety. It may be doubted that airlines will allow such cartridges or tanks to be taken on-board, particularly where flammable liquids are involved.

It is expected that military applications represent a significant market for fuel cell technology. The efficiency, versatility, extended running time and quiet operation make fuel cells a system tailored to the needs of the military. Fuel cells could provide power generation solution valid for portable military equipment land or sea.

The miniature fuel cells could offer great advantages over conventional solid bulky batteries and also eliminate the problem of recharging.

In the same vein, the efficiency of fuel cells for transportation would be reduced dramatically in the light of extra fuel needed for the manoeuvres. The vehicles would be able to travel long distances or work in remote areas for longer and the number of support vehicles, personnel and equipment needed in the combat zone could be reduced.

Since 1980 the U.S. Navy has used fuel cells in vessels for the study of deep sea and unmanned submarines.

In space applications, the combination of light weight, the supply of electricity and heat without significant noise and vibration, and with the added benefit of drinking water production, gave the fuel cell with considerable advantages over other alternative energy sources.

 

Why Fuel Cells for Marine and their poteintial in Naval Applications 

Due to their efficiency and environmental advantages seen before, fuel cells are suitable as marine or naval propulsion systems.

Nowadays, several countries and companies are involved in development projects consisting in the installation of fuel cells in different types of vessels. All of them are secondary propulsion systems, so the challenge is to achieve a fully electric powered ship using fuel cell technology.

This is considered to be achievable in 8-10 years time. However, there are some challenges to overcome. Moreover, there are already operative some commercial applications (submarines and small scale power generation).

The current framework regarding marine environmental issues helps the implementation of fuel cell technology on ships. Air pollutant emissions from ship engines are covered by Annex VI of the Marine Pollution Convention, MARPOL 73/78, of the International Maritime Organization. The revised Annex VI enters into force on 1st July 2010.

According to this new regulation, some regions are imposing Sulphur Emission Control Areas (SECAs), and in the Baltic and North Sea NOx free zones have been introduced. As well, the United States are looking to reduce pollution within 200 NM of its coastline. Therefore the trend will be the imposition of taxes and penalties.

On the other hand, the fossil fuels decline which implies higher and unforeseeable prices, and geopolitical dependency, among other problems, is another potential ally for the fuel cell technology.

To comply with these regulations new energy sources must be developed. The current lead technology in the search of substitute energy sources is the LNG (liquefied natural gas) burnt in thermal engines, being the fuel cells experimental at this stage.

As the fuel cell technology is new, there is a lack of regulations and standards regarding marine applications. The future IGF code (International Code of Safety for Gas-fuelled Engine Installations in Ships) will not cover the fuel cell systems.

Bureau Veritas and other classification societies are developing guidelines for the design, manufacture, performance and maintenance of marine fuel cell systems.

Some of the fuel cell advantages are very useful for marine applications . Apart from low vibration, noise and emissions, it is remarkable the high efficiency (up to 50%), the fact that a fuel cell system has fewer moving parts than a conventional engine, and also the different types of fuels which can be used. Some of these characteristics make the fuel cell technology more comfortable for the crew.

If it is not possible to use hydrogen directly, the alternative is to obtain it through a reforming system from other fuels such methanol, ethanol, natural gas, or even diesel, which has been tested by the US Coast Guard, using NATO F-76 diesel fuel, worldwide available.

Besides, fuel cells have a high operational flexibility, being capable, for example, of varying a 10% of the output power in only one second. Finally, the high temperature fuel cells (SOFC, MCFC) allow the combined production of heat and electricity (CHP).

Nevertheless, there are disadvantages in the use of fuel cells on ships. The main are:

  •  High cost.
  •  Low power density.
  • Long endurance under marine conditions not proven.
  •  Safety issues (hydrogen flammability and high pressures; methanol toxicity), and
  •  Low availability of hydrogen as a fuel.

 Most of them have real possibilities of being mitigated. The first three disadvantages are expected to be solved with the current experimental projects. They are due to the lack of maturity of the fuel cell technology: few manufacturers, little production, and the lack of regulations and hydrogen infrastructure.

Experiments with fuel cells in naval applications and their Analysis

Current projects running experimental fuel cell systems on ships are helping to grow up the marine fuel cell systems, improving the reliability under the hard marine conditions, and helping to reduce the costs, which are between 3,000 €/kW and 5,000 €/kW due the expensive materials used in the catalysts and electrolytes.

However, it is an unknown if a fuel cell can maintain at sea the same operational life that can reach onshore. The high capital cost of the fuel cell is already compensated by the lower fuel consumption and the saving in environmental taxes.

The hydrogen has a low energy density that implies the need of storing the hydrogen at high pressures. This fact, together with its flammability, results in specific safety issues on a ship, such as ventilation, additional safety and fire detection devices and fire fighting procedures.

High temperature fuel cells, SOFC and MCFC have their main applications in offshore ships, while low temperature (PEM, AFC) are more suitable for boats and submarines. The reason is the great size of high temperature fuel cells and the time required (few days) to reach the maximum temperature (and maximum power) and to cool down the system.

 As a result of the analysis of the different experimental projects that are currently in development, or have been launched in recent years, the fuel cell marine applications could be divided into the following groups:

  • Propulsion system for ships. The current developments are focused on coastal and onshore ships, supporting conventional engines. The intention is to achieve a fully fuel cell powered, offshore ship in ten to twelve years’ time. The high temperature fuel cells, such as SOFC or MCFC are very suitable for this application allowing, as well, a combined production of heat and electricity (CHP).
  •  Auxiliary Power Units (APUs). Using a reforming system or not, fuel cells could be an environmental and cost effective option to substitute the conventional APUs in the future. MCFC, SOFC and PEM fuel cells have been used in several projects.
  •  Main propulsion system for boats and small vessels. There are already some developments running, particularly in Germany( see below figure of Hydra boat in Rhine River ). The low temperature PEM fuel cells are very suitable for this application, although AFC systems have been also used. There are some hybrid systems, which combine fuel cells and batteries, and some of them even have rechargeable devices based on solar cells.

b2ap3_thumbnail_1.jpg

  • Small scale power generation. There is already a DMFC (Direct Methanol Fuel Cell) commercial system for sailing yachts, but these devices could use hydrogen in the future as PEM fuel cells.
  •  Submarines. Military research is also leading the fuel cell technology. The evidence is the great development concerning AIP (Air-independent Propulsion), used as a support system in some non-nuclear submarines to avoid operating without the need to access atmospheric oxygen. This capability increases the autonomy and, together with the silent operation of the fuel cell, improves the tactical features of the submarine. Several submarines of advanced countries are already in service, using a PEM based AIP, and there are more projects to come soon .
  • Unmanned Underwater Vehicles (UUVs). There are commercial systems based on low temperature Aluminium Oxygen fuel cells with applications in oil and gas exploration, fisheries and military applications, like mine reconnaissance.

Some examples of real projects, both civil and military, are detailed in the following paragraphs.

b2ap3_thumbnail_2.jpg

  1. Above is the photo of fuel cell been taken inside the hull of Viking Lady. The Viking Lady, is within the FellowSHIP project, operative since December 2009, and is probably the most important project involving fuel cell propulsion in large ships. It is a working ship supplying oil platforms in the North Sea, with a hybrid fuel cell/LNG system which provides electrical power and heat for the crew accommodation block.  Fuel cell technology of this power size, 320 kW MCFC, has never been installed before in merchant vessels and the highly innovative project is unique on a world scale.

FellowSHIP is being project managed by Det Norske Veritas (DNV), and has been designed and integrated by Finnish manufacturer Wärtsilä. Other partners are Eidesvik and the Norwegian Research Council. Operators say that fuel costs are 3,500 €/day less, apart from saving in NOx taxes, while the capital costs are only 10% higher. The system has met efficiency and environmental goals, and is being very useful to develop the new regulations in marine fuel cells.

Several tests found that the ship was only able to operate with fuel cells and batteries at low speed and low power, which are therefore advisable for use in port. This capacity is of great interest because the ship is designed to sail in the North Sea, where there are strict regulations on gas emissions. We can also see that fuel cells provide valuable support to the main engine when the ship is supplying fuel. Another important advantage was the reduction of vibrations, of particular interest when the ship is using the dynamic positioning system.

The system for generating electrical power, is depicted in below figure and it consists of fuel cells and a series of batteries by Corvus Energy (Canada). These are comprised of 6.5 kW lithium-polymer modules. This group of batteries is monitored by a control system that indicates when they are charged or empty, on or off. There is also a monitor to indicate the starting and stopping parameters(as mentioned in later figure)

b2ap3_thumbnail_3.jpg

b2ap3_thumbnail_4.jpg

The next step is to produce a 1 MW fuel cell reducing the size, to make it commercially viable.

2.       On the other hand, the U.S. Navy has been investigating since nineties the use of fuel cells for ship-board power with hydrogen sourced from diesel fuel.

3.       Wärtsilä, within the Methapu project, is also developing an Auxiliary Power Unit (APU). It is a SOFC 20 kW. The project is funded by the European Union with €1 million. The aim is to validate the use of methanol as a fuel in cargo ships. Other partners are Wallenius Marine, Lloyd’s Register, The University of Genoa and DNV.

4.       Regarding small boat projects, Alsterwasser is a boat which sails on Alster Lake (Hamburg) with a main propulsion system consisting of a battery and hybrid system (2x50 kW PEM), with hydrogen storage.

5.       In addition, Bureau Veritas is working on a Dutch project, HHHT (Hydrogen Hybrid Harbor Tug), with hybrid diesel/hydrogen (2x100 kW PEM), so that it is expected a 70% higher efficiency and substantial reduction in emissions. On the other hand, Hydra is the first fuel cell boat in Germany (5 kW AFC), certified to carry 22 passengers on the Rhine in Bonn.

6.       With regard to the small scale power generation, the German company SFC has developed a commercial methanol fuel cell for sailboats, to provide electrical current to appliances on board, running with fuel cartridges. The charging capacity ranges vary from 600 to 2,160 watt hours per day.

7.       The German shipyard HDW has developed with its partner Siemens an AIP system based on a PEM fuel cell, which is in service with the models U212 (Germany and Italy) and U214 (Greece and South Korea). The rated power is 2x120 kW for the second generation. The fuel is hydrogen stored in cylinders and the main propulsion system consists of conventional diesel engines.

8.       As well, the Spanish shipyard Navantia, together with UTC and Abengoa, is currently building a series of four submarines for the Spanish Navy. They will include an AIP based on a PEM fuel cell, and using bioethanol as fuel. A special processor will transform the bioethanol in hydrogen with a high level of purity. The main propulsion system consists of conventional diesel engines. The AIP is used in low power makeovers. Two possible alternatives for an AIP system are shown in below Figure.

b2ap3_thumbnail_5.jpg

9.       Finally, there are some examples of Unmanned Underwater Vehicles (UUVs), particularly based on Aluminum Oxygen fuel cells. The Norwegian Defence Research Establishment (FFI) started in 1995 the Hugin Project in cooperation with Norwegian industry.  The Hugin II has been in routine use by the Norwegian Underwater Intervention AS (NUI), which has operated the UUV for high-precision seabed mapping down to a water depth of 600 m. Today there is a complete Hugin family built by Kongsberg, as shown in figure below.

b2ap3_thumbnail_6.jpg

10.   The American Manufacturer C&C Technologies produced the first commercially operated UUV for oil and gas exploration. The payload consists of several sensors (camera, sonar, data link, etc). An UUV powered by a 4 kW PEM fuel cell system was completed by the Japan Agency for Marine-Earth Science and Technology . The fuel cell system generates electric power for the control electronics and propulsion system.

Future of the fuel cell Market

To achieve all the aims of these projects there is a necessity, in the long term, of a hydrogen-based economy. Perhaps the first country in reaching this status will be Iceland, where the government is intending to substitute fossil fuels by hydrogen produced from thermal energy, available in Iceland at low cost, with a six-phase plan.

Iceland may start with methanol powered PEM vehicles and vessels. The fishery fleet is a major fossil fuel consumer in that country and it is proposed to substitute diesel engines for fishing vessel power supply with fuel cell technology. These measures are widely supported by the population. Phase 4 will demonstrate PEM fuel cell boats. Phase 5 will replace the entire fishing fleet with fuel cell powered boats and in the next phase, Iceland will sell hydrogen to Europe and elsewhere. The last phase is expected to be finished by 2030-2040.

Regulations with respect to the Construction of ships using Fuel Cells

As we have seen above the Bureau Veritas is leading in the experimentation of Fuel cell in Marine Applications, it is better to discuss their guidelines. One set of guidelines, from Bureau Veritas, is described in greater detail below.

Materials

  • Components containing natural gas or hydrogen must comply with the provisions of the IGC Code (the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk).
  •  For non-cryogenic gas, particularly compressed gas, other non-metallic materials may be applied subject to special examination.
  •  Components in contact with hydrogen must be made of materials having good compatibility with respect to embrittlement and hydrogen attack phenomena. The normal operating temperature range for materials used in hydrogen components should be -40°C to +85°C (normal conditions including filling and discharging).
  •  References to hydrogen compatible materials and suitability demonstration testing are included in the guidelines.
  • Non-metallic piping carrying hydrogen gas may accumulate electrostatic charge along its exterior surface. Discharges from the external surface of the pipe may be sufficient to ignite a flammable mixture of gas or vapour in the surrounding environment. Care must be taken to effectively mitigate this risk.

General arrangement

  •  Machinery spaces characterized by its geometry and distribution system design safety control should be such that in case of leakage without loss of vessel's essential functions (propulsion, government and manoeuvre).
  •  The main distribution of spacious for fuel, distribution, storage, processing and use must comply with the conditions so that the extent of the danger zones is kept to a minimum. Besides presenting a simple geometry to avoid trapping explosive mixtures. Gas fuel storage, gas compressors, fuel processing systems, fuel cell modules and power conditioning systems must be located in different areas. Spaces containing fuel processing equipment must comply with the same requirements as machinery spaces housing fuel cell stacks.

Gas fuel supply

  •  All gas supply piping within gas-safe machinery space boundaries must be contained by a gas-tight enclosure, i.e., double-wall piping or ducting.
  •  Low-pressure gas supply piping (under 10 bar) located within ESD-protected machinery spaces equipped with an individual exhaust ventilation system may be accepted without a gas-tight external enclosure if the areas occupied by flanges, valves and other components of the gas supply system are gastight enclosed. (Arrangements in machinery spaces are such that the spaces are considered non-hazardous under normal conditions, but under certain abnormal conditions may have the potential to become hazardous.)
  •  Ventilation systems for gas supply line ducts must always be in operation when there is gas in the pipe system. Continuous gas detection is recommended for each gas supply line to indicate leaks and to trigger shutdown of the gas supply to the machinery space. The master gas fuel valve must close automatically if the air flow is not established and maintained by the exhaust ventilation system.
  •  Arrangements for provision of the necessary flexibility must be demonstrated to maintain the integrity of the piping system in all foreseen service situations. The guidelines pay special attention to the application of different types of valves and their location in the gas piping system.

Gas fuel storage

  •  The fuel gas can stored in liquid or high pressure, in these cases the gas storage tank must be of type C, thus fulfilling the conditions of the IGC Code.
  •  It must be possible to empty and purge gas and vent bunker tanks with gas piping systems. Inerting must be performed prior to venting to avoid an explosion in hazardous atmospheres in storage tanks and gas pipes. If hydrogen is used, fuel inerting is preferably achieved using helium, which cannot freeze and form a plug when exposed to cold hydrogen.
  •  Air must be prevented from entering the piping system and storage tanks in order to prevent the formation of flammable mixtures.
  • The system must be designed to withstand at least twice the anticipated number of filling cycles. The design and construction of compressed gas storage tanks must be in accordance with recognized standards (e.g. BV Rules, Pt C, Ch 1, Sec 3).
  •  Applicability of the standards chosen for the containment system to seagoing conditions must be demonstrated.
  •  Pressure relief valves must be fitted. The system must be designed to withstand the anticipated filling cycles for the lifetime of the ship.
  •  The guidelines provide specific recommendations for the onboard location of gas fuel storage tanks and batteries to protect them in the event of a collision or grounding, with 760 mm as the absolute minimum inboard distance from the side shell. For liquid hydrogen storage, the inner pressure vessel must be designed to operate at a temperature of -253°C. In this state, liquid gas can be stored at a maximum acceptable working pressure of 10 bar.
  •  Storage of compressed gas below deck may be permitted after special consideration if requirements are met regarding relief valve settings, thermal protection, gas detection, ventilation and fixed fire extinguishing.
  •  The storage tank and associated valves and piping must be located in a space designed to act as a second barrier for liquid or compressed gas leakage.
  • On ships where essential services depend on the fuel cell system, fuel storage must be divided between two or more tanks of approximately equal size, located in separate compartments.

Electrical equipment

  •   In general, electrical equipment and wiring may not be installed in hazardous areas (areas where an explosive gas atmosphere or a flammable gas (flash point below 60°C) is or may be expected to be present) unless necessary for operational purposes.
  •  The type of equipment and installation requirements must comply with the relevant area classification, considering three types of dangerous zones (0, 1 and 2)

Ventilation systems

  •  Ventilation is a key safety feature of gas-fuelled power systems. Good air circulation in all spaces is of paramount importance, particularly for preventing the formation of explosive gas mixture pockets in the space.
  •  The guidelines provide extensive recommendations for the forced ventilation of gas-related spaces and gas pipe ducting, and for the location of ventilation inlets and outlets and pressure relief outlets.
  •  The ventilation system for machinery spaces containing gas utilization equipment must be independent of all other ventilation systems.
  •  Ventilation must be monitored, including alarms. Electrical installations must be disconnected if ventilation cannot be restored for an extended period.
  •  Any ducting used for the ventilation of hazardous spaces must be separated from that used for the ventilation of non-hazardous spaces. Means must be provided to indicate any loss of the required ventilation capacity.

Detection, monitoring and control

  •  In order to provide the operator (or operating system) with the required information to safely operate the fuel cell power system, several detection and monitoring systems must be installed.
  •  Typical examples are gas detectors (at different levels of the Lower Flammable Limit (LFL) of the gas considered), loss of ventilation detectors, fire detectors, and gas pressure monitoring systems.
  •  The guidelines provide a detailed table (monitoring the fuel cell installation), highlighting the use of the different monitoring and detection systems, associated alarms, and follow-up actions (automatic shutdown of the main tank valve or automatic shutdown of the gas supply to the affected machinery space).
  •  For gas detection at 40% LFL, two independent gas detectors located close together are required for redundancy reasons, unless the gas detector is the self-monitoring type. Redundancy for the detection of critical hydrogen concentration is also considered in order to account for possible detector failure.

Risk analysis

  •  A risk analysis of the fuel cell installation systems must be performed to assess the consequences of a failure affecting the relevant systems and/or a gas leak.
  •  The required analysis can be an FTA (Fault Tree Analysis), FMEA (Failure Modes and Effects Analysis), HAZOP (Hazard and Operability Study), a combination of these techniques, or another type of analysis providing equivalent information.(as described in this blog)
  •  The risk analysis must be based on the single failure concept, which means that only one failure must be considered at the same time.
  •  Both detectable and non-electable failures must be considered. Consequence failures, i.e., failures of any component caused directly by a single failure of another component, must also be considered.

Tests and trials

  • Factory testing is required for materials, components and system assemblies. The complete installation must be tested on board.
  • Lists and descriptions of tests that must be performed, or were already performed (for type-approved equipment), must be defined and submitted for approval.
  •   Specific tests are needed for components in contact with hydrogen.(The relevant tests could be derived from approval tests for car hydrogen tanks.)
  •  The guidelines provide test recommendations for gas tanks and gas piping in accordance with the IGC Code and the interim BLG (Bulk Liquids and Gases) guidelines, including welding tests, post-assembly hydrostatic tests, and onboard system tests.

From the developments in course and taking into account the commercialized products of fuel cells in marine and naval applications, it can be concluded that this is a promising technology in this area.

Although durability tests must be checked, experimental projects show that fuel cells give rise to low emissions in the marine medium. The apparent problem of costs will probably disappear due to that high oil costs are foreseen and also due to the savings obtained from emissions reduction.

In addition, although volume reduction of fuel cell systems must be achieved, the weight does not seem to represent a big problem in marine systems, and to centralize hydrogen suppliers in harbours seems to be feasible.

Hits: 1968
0
Golden Bollard 2017
SEARCH MEMBERS

SEARCH MARITIME MEMBERS

The Global Maritime Community has many type of players and many are members of this Club. You may find them as per your need by using the filter below

Search Member by Rank / Role

Tools