Surveillance

Issue 1 | 2017

In this issue

Leaking engine roomsPage 3 Understanding towagePage 4 How to maintain a Global Surveyors’ networkPage 8

Cargo hold firesPage 10

IMO container weighing rulesPage 12

The effect of eco-friendly measures on marine diesel enginesPage 14

While corrosion is a chemical process, in some cases it is caused, or reinforced by, microbiological activity. This is a type of local corrosion where bacteria show a fast development, producing chemical agents that accelerate the corrosion process.

This highly underestimated phenomenon is known as MIC (microbiologically influenced corrosion).

In recent years, BMT Surveys has seen an increasing number of cases of leaking engine rooms caused by very local perforations of the ship’s plating. And this happened despite the recent Class renewal in which bottom inspection and thickness measurements showed that the plating was sound. Typically, these perforations were mainly crater shape with sloping sides while the plating surrounding the craters still measured its optimal, sound thickness.

This form of corrosion is mostly found in engine rooms because these bacteria flourish in carbonaceous bilge water, which of course, makes these little steel eaters very difficult to detect. They can be found under floor plates where dirt is often present in abundance, particularly infecting the places most difficult to reach or clean. Salt water vessels – being exposed to high levels of sodium chloride – are for this reason very susceptible to this form of corrosion, unless they are, for example, fitted with a protective coating. That is why this phenomenon is mostly seen in somewhat older ships. The hidden character of these old ships is what makes them so risky. The development of these perforations is sudden and unexpected and the consequential damage of flooded engine rooms can be significant when you think of engine failure, towage costs etc. Exterior bottom inspections do not expose these perforations because the source is found on the inside. Finding one of these craters during random thickness measurements would therefore be pure coincidence.

Furthermore, cleaning the bilges for a thorough inspection of the inside of the plating is not general practice in the case of Class renewals. Consequently, it is important - once a ship is 15 years old - to remove the floor plating in the engine room, to clean the bilges with a pressure washer and preserve the inside of the plates. Prevention is better than cure in this case as well, because it is not a question of whether these MIC problems will arise, it is only a matter of time before they will.

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A warm welcome to the latest issue of Surveillance. In this issue, we look at a number of challenges being faced by ship owners and operators around the world.

We discuss the risks of towage and how better to understand them in an often complex environment.

We hear from Carlos Maenhout on corrosion matters, and from Juan Christoffels on the effects of eco-friendly measures on marine diesel engines. Our Director Risk & Quality, Olivier van der Kruijs discusses how important it is to have, in today’s globalised industry, a ready supply of surveyors to meet the needs of international clients and how BMT is managing this need through a Global Surveyor Network.

Finally, we talk to Yrjo Migchelsen on the, often less reported, issue of cargo hold fires caused by defective lighting systems and hear his suggestions for how owners and crew can check for this problem.

We hope you enjoy this issue and welcome any feedback you many have on any of the subjects included.

Leaking engine rooms caused by “steel eaters”

Editorial

Jeroen de HaasManaging Director, BMT Surveys (Rotterdam)

Carlos MaenhoutManaging Director, BMT Surveys (Antwerp)

Bruce VerweijManaging Director, Verweij HoebeeGroep

Carlos Maenhout, MScManaging DirectorBMT Surveys, Antwerp

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Towage

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Understanding the Risks In case of a towage, underwriters usually determine under which conditions they are willing to accept the risk. This is also true for the choice of the surveyor, although in everyday practice it is usually the insured that ultimately appoints the MWS (Marine Warranty Surveyor).

Underwriters are aware that in some cases, even if professional parties are appointed for the job, towage can end in a failure.

Unfortunately, conditions such as poor preparation and insufficient experience of towage companies and her crews are still causes of damage. The complexity of the different types of towage such as deep-sea towage, short sea and harbour towage is often underestimated. Situations, in which the size and strength of the towing wire and the catenary and subsequent (over) loads of the tow line are incorrectly calculated, are not an exception.

But also factors such as, changing weather conditions, currents, navigation speed or the dynamic pull on the tow may cause danger for towage and crew and may cause damage to cargo, ship and environment. The risks are therefore high, as well as the interests involved. Time to reflect and consider towage risks in a bit more detail.

Where does it appear to go wrong in some cases? Most incidents are caused by loss of the tow connection, followed by the inability to restore this connection, creating dangerous situations that could even result in stranding. Tow wires can easily break as a result of chafing against the tow bar of the tug boat, but more often by the lack of knowledge about catenary of the tow wire in relation to the depth of the water.

A tow wire between tug and tow can have a great length. The line must always have a certain catenary, because it must be able to cope with wave motions of tug and tow. It may not, however, hit the seabed either because this will damage the tow wire causing it to break within a couple of hours only. A connection between tug and tow in deep sea operations may never be a tight line. There are numerous influences that make this long line necessary.

When the weather and sea are calm, the tow wire may be shortened. The captain, however, must be able to assess the appropriate length and the force the tow line may be exposed to. If, for example, weather conditions deteriorate, the tow wire will be lengthened.

Peak loads in the tow wire will thus be better absorbed. Sometimes the engine room is asked to reduce the propulsion. This is done to keep the forces on the tow line within the appropriate limits. If a tow wire or other part of the configuration breaks, most of the time, this is in heavy weather conditions and could place the tug boat and its crew in a dangerous position.

It is often a tough job to restore the connection. In the middle of the ocean there is plenty of time and space, but when you are close to the shore, acting fast is an absolute must. Anchors should be ready to be dropped at any moment to prevent collisions and stranding. In such cases you must be able to rely on the experience of crew and equipment.

A tow connection

A tow connection somewhat resembles an iceberg, most of it you don’t even see because it is under the water as is shown by the figure below. Therefore, shipping rules dictate that it is of vital importance that no ship or yacht passes between a tow connection.

The main connection of the towage is of course the tow wire itself, which is usually on a drum. The towing wire is often hundreds of meters long, sometimes even up to a kilometre in length, or more. The tow itself is fastened by means of a triangular connection, usually a chain. The technical term for this chain is “bridle”. A bridle consists of two equal lengths of chain connected on both sides of the tow that are combined with shackles to the delta plate (or monkey plate). Pennant wires or pennant chains are then connected with shackles to this delta plate.

In most cases, a stretcher is connected to this pennant wire and

serves to absorb sudden shocks and tensions on the tow line during the journey. Nowadays, they are made of polyprop/pspp/composite which makes them easier to handle. Previously stretchers made of nylon and hemp were also used, however these were thick and heavy, especially when wet and therefore very hard to handle.

There are different combinations of tow formations which consequently are also certified and insured in different ways. Current rules and regulations are not always clear on the definition of “tug” or “pusher tug boat”. A tug boat is specifically designed and equipped for towing ships, structures and floating objects and not for independently transporting goods. A cargo vessel towing a ship does not automatically make it a tug boat.

A specifically designed tug boat operating in ports is clearly a tug boat, but each ship that is not designed as a tug boat, but tows another ship is, however, according to regulations, still designated as a “tug boat.”

Reducing risk of failure In order to reduce the risk of failure, it is quite common that underwriters require a towage expert to carry out a towage approval survey prior to the journey as not only the cargo, the towed ship and the environment are vulnerable in a towing operation.

Due to shipping regulations it should be taken into account that obligations to third parties may arise from such a towing operation as well. Often a towage approval is therefore a condition of insurance cover. Although liability claims can be avoided by a proper preparation and sound risk assessment in advance, still, there are many reasons why a tow could fail during the voyage.

During a towage approval, the surveyor checks whether all reasonably necessary precautions have been taken.

This includes a documentation check but also a physical inspection of the tow, tug, machinery, winches, equipment, fuel quantities and (emergency) towing gear. Certificates are verified (without testing being done) and calculations will be made to check if the power and capacity of the tug is sufficient for the tow and voyage in question.

Navigation charts are checked to verify these are complete and up to date. Further, the tow arrangement as a whole is considered as well. As to the complete scope of work required for the approval of tows, reference is to be made to industry standards.

On completion of the survey, the surveyor will issue an approval certificate which may include certain navigational limitations for the voyage.

After the tow combination has sailed, the surveyor usually remains involved in tracking the tow as well as the weather situations and advice may be provided to the Master in trying to avoid severe weather conditions.

Summary

Many years of experience in damage claims have shown that the involvement of a towage expert in the preparatory and execution phase have significantly reduced the risk of a failure. However, it should also be well understood that a towage approval certificate is not a guarantee for a successful completion of the journey and many approved tows are still lost at sea.

There are many reasons for failure of an approved tow, simply because not every potential risk is assessed in the approval stage and unforeseen situations may occur. After all, the sea can still be a rough environment and design conditions can be exceeded, even if all the requirements have been complied with.

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TOP VIEW

SIDE VIEW

In addition to its own offices, BMT Surveys has a world-wide network of associates providing survey services to BMT. These associates are existing survey companies with a proven track record of being equipped and capable to perform surveys in line with the company’s requirements.

This network provides the ability to quickly respond in case of an emergency or urgent attendance for evidence gathering, damage assessment or ship inspection.

The benefits are obvious: short lines of communication, better quality, reduced costs for principals and particularly, a wide variety of possibilities through shared knowledge, experience and disciplines.

With the world changing at a rapid pace, the need for such a network is evident.

Several marine survey companies offer network services on a sub-contracting basis, ranging from the use of companies from a simple entry in the Yellow Pages to an established relationship as part of its quality management system.

While BMT has opted for the last, it is certainly not so that there is always a choice of surveyors to pick from and locations can be so remote that there is no other possibility than to accept availability.

However, even in such situations there is significant added value by co-ordination and supervision by somebody who understands the

client’s needs and who has a deep understanding of the (technical) matter at stake.

Direct access to an exclusive network caters for a demand in the shipping world of today.

This becomes evident for instance from the many requests for international damage surveys but also from the great number of risk inspections BMT is requested to carry out all over the world.

When operating a worldwide network it is important to establish the selection criteria for companies to join the network and, equally important, to have processes and procedures in place to ensure the quality of the service.

“We always remain our principals’ direct contact, in this way keeping the lines of communication short”, explaines Olivier. “We have, over the years, established a very extensive and successful network. But before we enter into a cooperation with a third party, we naturally make sure that this party meets our own quality standards.

We take into account background and education, we are interested in their experience and read publications on previous assignments, and we check their references. Together, these aspects provide a good company profile.

After completion of each assignment, evaluation is of crucial importance for it is decisive in determining the possibilities of future co-operation. BMT Surveys keeps a careful record of the performances and references of co-operating relations through an online platform. Making this system available for all BMT Surveys offices, ensures the possibility of monitoring the quality of co-operation and the ability to offer our clients high-standard expertise at an international level.”

“Our clients’ demand for international engagement of our expertise is still growing. We are able to fully assist them by approaching our world-wide contacts, checking and translating reports and making clear price agreements”.

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How to maintain a Global Surveyors’ Network

Olivier van der Kruijs, Director Risk & Quality at BMT Rotterdam, has a Bachelor of Science in Nautical studies and Marine Engineering. Olivier has seven years seagoing experience as Maritime Officer with engineering specialisation on board of different vessels. He is a qualified lead auditor for ISM systems.

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BMT Surveys Global Surveyor Network

Additional Heat Sources Apart from cargo hold lighting, there are several other heat sources on dry bulk carriers such as: heated fuel-oil bunker tanks, poor electrical wiring, carelessly discarded smokers’ material.

As well as these, hold lighting requires particular attention as the amount of heat and energy generated by a typical 500 Watt halogen light can be significant. Research has shown that temperatures may be as high as 700 degrees and that the heat of the glass cover may well be sufficient to set cargo on fire.

The required temperature for a substance to spontaneously ignite in a normal atmosphere without a flame or spark is referred to as the auto-ignition temperature. For most organic solid substances, this temperature lies around 300-500 degrees.

Consequently, it will only be a matter of time before a hold light over-stowed by cargo will develop sufficient heat and energy to ignite the cargo.

Investigating a Fire Obviously one of the questions for investigators to answer is “why were the hold lights left “on” after cargo operations had been completed and the hold was closed?” “Had the crew been ignorant or was it an unnoticed defect in the electrical system which made the crew believe the lights were off?”

The basic principle with regard to hold lighting systems is to isolate the system prior to loading bulk cargoes. This can be achieved by removing the fuses and / or circuit breakers of the system, by switching the key-operated switches for the cargo hold lights to the “off” position or by disconnecting the plug of a light from its connection box etc.

In one particular case, it was found that the vessel’s crew had adhered to the required procedures in a proper manner: the key-operated isolating switches had all been switched to the “off” position and the Master had removed the key switches and held them in his office to avoid accidental operation by one of the officers on the bridge.

Despite these efforts, the holds lights were still “on” when the ship left port with the cargo in contact with the hold lights. Consequently, a short while later, smoke was coming out of the cargo holds and emergency measures had to be taken to control the fire and to bring the vessel in safely.

Defective Design During testing of the systems, it was discovered that even with the key switches in the “off” position and the keys removed, section(s) of the cargo hold light system were still energised, leaving them on. Apparently, the switches were not functioning as designed.

Further investigations found that the actual electric cargo light systems were different to the electric circuit diagrams (wiring arrangements) provided by the shipyard in China.

Furthermore, it appeared that, in some instances, the wiring of the cargo hold lights was not connected to the key-operated isolating switches at all. It also appeared on the key switches were sometimes not even mentioned in the electric circuit diagrams and on the bridge console panels.

For these reasons we would like to recommend that vessel’s owners / crews inspect the vessel’s cargo hold light system and electric wiring diagrams in order to verify procedures concerning the operation of cargo hold lights and, if and when necessary, modify on board procedures accordingly. Further, the use of LED floodlights may be considered as these produce a much lower temperature for the same brightness, thus reducing risk overall.

Articles concerning cargo fires mainly focus on those caused by the nature and properties of the cargo itself, such as cargoes prone to self-heating, spontaneous combustion or cargoes developing a chain-reaction once exposed to external heat.

Less attention in literature is given to hold fires caused by an external heat source such as hold lighting. A number of recent fires on board vessels with dry bulk cargoes has led us to explain how these fires are caused and what can be done to reduce the risk of occurrence.

Cargo hold fires caused by defective hold lightingsystemsby Yrjo Migchelsen, BSc CEng Marine Fire Investigator

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The ship’s crew determines the deadload by calculating the difference between the weight of the ship, in part by the container weights indicated on the documents submitted, and the actual weight of the ship as determined on the basis of the draught marks at departure. In the optimal situation in which all container weights are exactly on the mark, the dead load should be virtually zero.

Remarkably, it was established that the dead load figures did not significantly drop since 1 July 2016. The average before 1 July was around 1.85% of the total vessel weight, four months after that date still shows an average of 1.77%.

On a ship with a total weight of 100,000 tons, this is 1,770 tons, in other words, the total weight of approximately 60 fully loaded containers of each 30 tons. Some ships even reported dead load numbers of more than 4,000 tons. An interesting fact was that in almost all cases the weight on board was higher than the weight reported in the cargo documentation.

Meanwhile, there are stories circulating about owners verifying the Vertical Gross Mass (VGM) declaration with spot checks, and in this way were able to determine that the containers’ weights were higher than allowed by international regulations (CSC). In those cases, the reported VGM was just below the maximum limit.

Conclusion

In conclusion, there were sound reasons for regulating the determination of container weight before containers are loaded on board a ship, and the methods referred to suffice.

Supervision by the authorities, however, seems to be lacking, raising the question of what will happen to a regulation that is not monitored.

This may very well lead to the situation in which parties less concerned with safety in the shipping industry, simply tick the box that says checked instead of actually reporting the correct weights.

To improve safety at sea, The International Maritime Organization (IMO) has drawn up a regulation making it compulsory to verify the gross weight of export containers.

This regulation, implemented on 1 July 2016, has impacted on the entire transportation chain. Without verification of weight, containers are not allowed to be loaded on seagoing vessels. The shipper of a container needs to provide a statement to the carrier stating the verified gross mass of the container and its contents.

IMO container weighing rules

- a first evaluation

During the introduction of this new regulation, various parties in the “container chain” were quite divided on the issue. According to the shipper’s association, the regulation gave the unjustified impression that incidents were mainly caused by shippers reporting incorrect container weights. Furthermore, shippers argued that the implementation of the regulations forced considerable expense onto the industry, while other important factors were overlooked and real problems were not tackled.

Based on our own experience as a surveying company, we have seen that reporting wrongly declared container weights can play a role in incidents.

For example, a wrong container weight can cause a heavy container to be loaded too high on deck causing certain forces to be exceeded. It has been approximately seven months since the implementation of the rule and despite the scepticism in the market there are hardly any examples of containers being left on the quay because the weight was wrongly or not declared. This, however, raises the question as to whether the reported weight was actually checked by the shipper or if a statement was simply issued without determining the weight.

Monitoring the regulations, in the first instance, is the responsibility of the authorities and the question is whether they are capable (or prepared) to perform these checks.

American authorities indicated, at a very early stage, they did not intend to monitor this process because they believe the responsibility lies with industry itself and not the authorities. We now await the first shipping incidents that gives cause to weighing the containers to check this with issued statements. This will be a very interesting case.

BMT Surveys Collects Independent Data In the meantime, BMT Surveys carried out an investigation on board several hundreds of container ships during April – October 2016, collecting data on the dead load of a departing ship. Dead load is a technical term indicating the unknown weight on board a ship.

Jeroen de Haas, Managing Director of BMT Surveys Rotterdam, shared his findings and conclusions on dead-weight investigations at the latest IUMI conference in Genoa.

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Over the years it has become more and more clear that we must take care of the environment before it’s too late. In our business this means, for instance, that engines must be less polluting and exhaust gas emissions must be limited to the extent possible.

In order to achieve the above, there are several eco-friendly measures to consider. Unfortunately, if not executed properly, some of the measures can have a negative effect and can even be fatal to the engine.

One of the eco-friendly measures to limit diesel engine pollution is to decrease engine output by restricting the fuel pumps. With this restriction, engine consumption will be decreased which is, of course, a good thing for the environment. However, if this restriction is not done correctly, it may result in a seriously damaged engine.

In selecting the engine of a vessel it is normal to take into account the ability to overpower the maximum power needed by 10 to 15%. However, in situations in which it is not necessary to deploy all available power, the engine can be restricted in output. In this case the designed overpower will decrease as well.

The effects of eco-friendly measures on marine diesel engines

There is a possibility that due to the restriction, the available engine output power is no longer sufficient for normal operations. In this case the restricted engine is not able deliver enough power and the power demanded by propeller or generator will start to slow down the engine in revolutions.

When the revolutions of the engine are decreased by an external cause (propeller or generator), the governor of the engine wants to increase the fuel volume injected in the engine.

However, since the control levers of the fuel pumps are restricted, the fuel volume cannot reach the level needed and the engine cannot de-liver the necessary power, causing the revolutions to drop even more.

As a result, the turbocharger of the engine will decrease in revolutions as well, resulting in a decreased scavenging air pressure. Subse-quently, the fuel/air mixture will be out of balance causing poor com-bustion of the fuel, resulting in high temperatures and serious pollution of the engine.

The engine parts directly in contact with the increased temperatures will suffer from increased thermal stresses.

A pretty technical story which not everyone will understand. However, the message behind it is that when a diesel engine is restricted, it is of great importance to also reduces the demanded power. In case of a main engine or bow thrusters, the propeller must be adjusted to the available power.

Juan ChristoffelsSenior SurveyorVerweij Hoebee Groep

BMT Surveys (Rotterdam) B.V.Guldenwaard 1413078 AJ RotterdamThe NetherlandsTel: +31 (0)10 479 0311Fax: +31 (0)10 479 1466

Email: rotterdam@bmtsurveys.com

BMT Surveys (London) Ltd.1st Floor, International HouseSt Katharine’s WayLondon E1W 1AYUnited KingdomTel: +44 (0) 207 101 2114Email: london@bmtsurveys.com

BMT Surveys (Delfzijl)Duurswoldlaan 29936 HA FarmsumThe NetherlandsTel: +31(0) 596 7450 02Fax: +31(0) 596 7450 03Email: delfzijl@bmtsurveys.com

BMT Surveys (Amsterdam) B.V.Zekeringstraat 36D1014 BS AmsterdamThe NetherlandsTel: +31 (0)20 584 0800Fax: +31 (0)20 584 0801Email: amsterdam@bmtsurveys.com

BMT Surveys (Geneva)1-3 Rue de ChantepouletGeneva1201SwitzerlandTel: +41 (0) 22731 0892Email: geneva@bmtsurveys.com

BMT Surveys (Antwerp) N.V.Kapelsesteenweg 2862930 BrasschaatBelgiumTel: +32 (0) 3664 0279Fax: +32 (0) 3605 1963Email: antwerp@bmtsurveys.com

BMT Surveys (Melbourne)Level 5, 99 King StreetMelbourneVIC 3000AustraliaTel: +61 438 544 859E-mail: australia@bmtsurveys.com

Verweij Hoebee Amsterdam Verweij Hoebee Groep Osdorper Ban 17bc1068 LD AmsterdamThe NetherlandsTel: +31(0)20 - 6107260Email: info@verweij-hoebee.nl

Verweij Hoebee BarendrechtVerweij Hoebee Groep Achterom 662991 CV BarendrechtThe NetherlandsTel: +31(0)180 - 623236

Email: info.hoebee@verweij-hoebee.nl

Verweij Hoebee Den HelderVerweij Hoebee Groep Het Nieuwe Diep 331781 AD (Den Helder)The NetherlandsTel: +31 (0) 223 - 82 03 96Email: info@verweij-hoebee.nl

BMT Surveys Verweij Hoebee Groepwww.bmtsurveys.com www.verweij-hoebee.nl