Double hulls are not the panacea

01 May 2004

Continuous improvement in quality and safety is a must for the maritime sector. "The public should be more aware that ships are the best means of transport for the safety of lives and protection of the environment," said Ugo Salerno, CEO and director general of RINA and chairman of the International Association of Classification Societies (IACS) talking at the Tanker Operator Conference in London in February.
Ships have been designed by means of highly sophisticated computational tools, such as structural finite element analyses, and built according to stringent industry production standards. "This has led to significant design and construction optimisations, ensuring that, when ships leave yards fully in compliance with statutory and classification requirements, they are safe and fit for purpose provided that they are properly operated, inspected and maintained," explained Salerno.

Less steel
The one problem with this is that it has led to ships with significantly less steel weight than 30 years ago, extensive use of high tensile steel, and enhanced means for controlling corrosion and reduced corrosion margins, keeping shipbuilding costs at the lowest possible price.
"In that respect, the evolution from single to double hull tankers has not been a panacea to solve all problems, as the internal structures in the double hull spaces are more complicated and difficult to inspect and maintain than for single hull tankers," says Salerno. He summarises that there is a genuine need to raise the structural standards for shipbuilding and ships in service. Bernard Anne, Managing Director of the marine division of Bureau Veritas, talking at the CMA Conference in April tells us that while double hulls for tankers have had the effect of reducing small spills, if we want to tackle the headline grabbing spills which impact the industry so badly, a new set of priorities are needed. He highlights these as:
l Better availability/safety of machinery
l Enhanced manoeuvrability and navigation systems
l Explosion prevention (to avoid fatigue cracks in longitudinal bulkhead).
The big three class societies, i.e. Lloyd?s Register (LR), American Bureau of Shipping (ABS) and Det Norske Veritas (DNV), have done much to promote tanker safety within IACS with the Joint Tanker Project (JTP) for which the drive is to create common rules for scantlings for double-hull tankers of 150m in length and above.
Terje Staalstrom, DNV?s head of class and quality management, told The Motor Ship that the draft rules will be published in early June. He is then expecting to get reactions from the whole industry "but, from what I have seen and from presentations we have made, most of the industry appreciates it in this case and it should be IACS common standards harmonised and at the one level."
Owners will then not have to deal with ten different sets of rules as they do now within IACS alone. "We don?t expect to lose clients ? if you raise the standard of the newbuildings, you raise the standards all across the board ? all the shipowners will be affected by the same standards so, as long as you do it across the board you still maintain a level playing field so nobody is able to skip out of it and find another standard because we have been clear that once these rules are published we will not class a tanker that does not meet these rules," explains Staalstrom.
IACS is currently working on both tanker and bulk carrier rules and, once these rules are published, then it will start looking at other ship types.
"First of all container carriers ? that?s the third one but, right now I think we have a huge task just getting the rules for tankers and bulk carriers ready so don?t expect us to start on other sip types at least until next year jokes Staalstrom.
He explains that a lot of the technical requirements of bulk carriers have already been harmonised through unified requirements in IACS or the IMO rules for the strengthening of bulk carriers, "There are already many more common requirements for bulk carriers than we have for tankers," he says, "although the added challenge is to harmonise the rules for tankers and bulk carriers."
"If you have a tanker and a bulk carrier operating in the North Atlantic they will both face the same wave spectra and have the same environmental loads ? you will have to use the same fatigue procedures etc so there are a lot of similarities when it comes to bulkers and tankers for external loads and also for the calculation procedures," Staalstrom told The Motor Ship. Harmonising the basics for the two rules has been started, which he says is not an easy task as all the class societies are more than one hundred years old. The safety philosophy was developed a long time ago and everyone has their own particular views on how it should be done.

Safety is paramount
While these new rules mean that tankers will not end up weaker or less robust than with any of the existing three rules, tanker owners can rest knowing that "we?re not taking the strictest requirements from each society and adding them on top of each other," says Staalstrom, "that would be the wrong way to approach this ? so it?s not just a cut and paste ? we had to go back to the basics and start with environmental conditions and the whole structural response and build it up from scratch."
It is very much in line with the submission IACS has to IMO on what are the safety goals and what are the safety acceptance criteria and that is where the start will be.
Whether that means bulk carriers will be required to have double hulls is still in debate. Anne says that the shipping industry is far from convinced of the need for double hulls, and argues there is little operational experience to justify such a move.
He says that the MSC will meet in May to consider this requirement, but there is no certainty that it will become mandatory.
Anne says that there are both advantages and disadvantages to double hulls and highlights the reduction in grab damages on side shell due to operation as an advantage ? "it will reduce dramatically the risk of water ingress in the cargo hull."
Among the disadvantages, he highlights that it is clearly not the most cost-effective solution to address the risk of side-shell failure as "it will imply loss of cargo capacity for Panamax and smaller vessels," and "the maintenance aspects are also to be considered."

Explaining seaworthiness
"Seaworthiness is really quite a wide issue and for a ship to be seaworthy means that it is fit for the voyage that it is going to undertake and, of course, the class certificate is a very important aspect of it but it doesn?t cover all the angles," says Staalstrom. He explains that the statutory certificates, typically the ISM will cover a lot of it but still you have to have qualified people, well-trained people and management systems in place. It is really something the master has to make a decision on before he leaves port.
For a coastal tanker on the coast of the US or the coast of Europe, the requirements for seaworthiness would need to be different from a tanker exporting oil from Murmansk. Trading patterns, environmental conditions and navigation hazards faced should all have an effect on the question of seaworthiness.
Staalstrom remembers last year when there were a lot of discussions regarding two relatively new tankers going into Russia in the Baltic to pick up cargo
"They had an ice class from ABS, but the ice conditions in the Baltic were such that they should have had a stricter ice class. It was not ABS? fault as it had issued a certificate according to the condition of the ship but the master, the shipping company and the charterer should have known that the ship was not fit for purpose ? it wasn?t designed to operate in those conditions." This is a typical example of where seaworthiness depends on the trading pattern and the qualifications of the crew and the people handling the vessel.
He points out two aspects that could come into play here:-
One is the insurance ? the hull and machinery underwriters might say that classification requirements, or the statutory certificates have been exceeded by operating in environmental conditions that were not considered. And, in this case could refuse to pay a claim if something happened
Staalstrom told The Motor Ship; "then, of course if this is a monitored sea area like you have in parts of the Baltic, the coastal states might say that this ship is not permitted to cross through our waters and that brings us to the interesting discussion with particularly sensitive sea areas like we?re in with Brussels. The EU would like to see the whole of Europe as a particular sensitive sea area and if that was accepted it would give the coastal states the authority to expel from their territorial waters ships they deem are not, let?s call it, seaworthy. So, seaworthiness is not a clearly defined issue."
If an insurance company can prove the ship was operating outside the scope of the certificates, they would have a strong case for not paying out in case of a claim. "But a class certificate in that context is very important because the class certificate spells out for what the ship is designed ? some operational limitations ? so it?s an important element of this seaworthiness, but it doesn?t cover all the aspects."

Crew costs
The STCW convention stops owners skimping on training of certified crew and whether those requirements are being met is being checked by the port states. So, at least for officers, there is no easy way to escape training. However, it is not the same for the common rating, or able-bodied seaman, who don?t have the same qualification requirements. One of the things DNV is looking at is how it can improve the situation and that is where its SeaSkill programme comes into play.
Staalstrom told The Motor Ship, "we are just launching it ? it came about because some countries, in particular Holland, have a requirement for personal certification," which is where the class society gained its experience.
"So far, we have certified a number of training academies and training schools but it is mostly their quality system, somewhat similar to ISO 9000 quality management system but what we are now starting to look at and what the European Commission is interested in, which is even if they have a good quality management system what is the quality of the product ? what is the quality leaving the system," he asks.
The next step is to look at the quality of people coming out of training academies. The Motor Ship suggested that it would have to mean surprise visits and test of people coming out of these academies to which Terje replied, "I can see our SeaSkill programme being part of our standard testing, which provides for a certain minimum level of content for the course and standardised testing to see that someone coming from the Philippines and Lithuania and Norway and Denmark have the same minimum scope of knowledge."
Many are biased about certain countries and nations without really having a good background knowledge about the quality of education. "I don?t want to criticise any country but it is more important to get a better understanding about what is really the course content and what is the quality of education," says Staalstrom. However, he is quick to point out that DNV is not keen on getting involved in the pay issue. "What we are prepared to do is look at the physical conditions and the working conditions onboard the ship to see that they meet the [ILO] convention ? something that you can check physically but I think class societies are really not willing to get into the debate between a ship owner and ITF and an employer and employee regarding, let?s call it, remuneration, compensation and benefits. I don?t think that is our area really," he explains.

Security threat watch

Maritime security has become a pressing issue for the shipping industry, with serious questions arising about the industry?s ability to comply with the International Ship and Port Facility Security (ISPS) Code in time for the July 1, 2004 deadline.
To aid owners and operators, the Lloyd?s Register Group has launched a web-based maritime security information service called SeeThreat.
The ISPS Code requires company security officers (CSOs) to use their security assessments and other information as the basis for advising their ships about the threat levels they may encounter, such as terrorism, piracy, labour disputes and civil unrest, among others. SeeThreat assists informed critical security decision making by presenting the results of daily, historic and global information news relevant to the ship at its operating locations in an easily interpretable format.
SeeThreat, which was developed in collaboration with QinetiQ, constantly monitors maritime security news information for locations and threats specified by the operator to meet its own needs and the relevant ISPS Code threat levels. Rising threats are presented graphically at chosen locations and levels and are displayed by amber/yellow and red warning icons.

Managing risk

ABS? Marine Engineering Systems group has a new tool to help operators looking to develop effective maintenance policies and practices based on rational risk assessment approaches, rather than relying on historic maintenance operations data. The group has released the Guide for Survey Based on Reliability-Centered Maintenance, which claims ABS, offers an approach to preventative maintenance that focuses ultimately on improving machinery reliability, thus reducing operator downtime.
Using a reliability-centred maintenance approach (RCM) helps understand how systems function, how systems fail and how to determine the consequences of the failure so the most appropriate maintenance task can be selected to prevent the failures, explains Robert Conachey, principal engineer, ABS Marine Engineering Systems. "Before this type of methodology, maintenance plans were created by past experiences which are not always the most appropriate for the complex systems of today or address unexpected failure modes," he adds.
"Determining the machinery spare parts to have on inventory based on risk assessment is very appealing in commercial terms," he says. The worst-case scenario for machinery problems can ultimately lead to loss of propulsion or
Applying RCM methods set forth in the guide may be credited as satisfying the requirements of special continuous survey of machinery. Conachey says upon completion of a satisfactory survey a certificate of approval for reliability-centred maintenance can be issued by the attending surveyor. A notation, if appropriate, will be entered in the ABS Record. RCM notations can be issued for equipment related to the propulsion system RCM (PROP), the fire extinguishing system RCM (FIRE) or the cargo handling and safety equipment for a tanker, liquefied gas carrier or chemical carrier RCM (CARGO). Machinery systems and equipment associated with offshore drilling rigs that are in compliance with the Guide for the Certification of Drilling Systems will be distinguished with the class notation RCM (CDS).

Major milestone

DNV has reached a very important milestone in passing the 100 million gross tons of class tonnage for the first time in its history. "There are only four societies that have reached this milestone, NK, LR and ABS and now DNV and to us it?s a big milestone," says Staalstrom. He told The Motor Ship that DNV?s market share is slowly creeping up at 17% and if you look at the comparison between the societies, NK and DNV have had steady growth over the last ten years. This growth has come from what he describes as the liquid cargo sector ? tankers, chemical carriers, LNG and LPG. "That?s the strength," he explains, "and then not so much tonnage but valuable equipment in the oil and gas support side ? supply ships, floating production units, shuttle tankers and if you look at the value of the fleet, it is probably the most valuable segment."
DNV has done well in the fast ferry market but there has not been too many newbuildings of late and, as he jokes, these vessels do not have much tonnage or value. "If you?re looking at value," he says, "we are doing very well in cruise and passenger ships but the number of ships is small even if the value is high. Right now there is not much happening in the cruise market ? they are sitting and waiting ? there seems to be an overcapacity, which they have to absorb."

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