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REPORTING · 11th December 2010
Merv Ritchie
The prospects of Super Tankers carrying Canada's crude bitumen through Douglas Channel to Asian destinations has been provoking emotional reactions on both sides of the issue. One of the statements made regarding the transport of this product, and others, is the state of the technology today. The double hulled and new tankers, whether they be VLCC, ULCC's, Supertankers PanaMax, these newest ships and their technology are stated to be "State of the Art".

First a Resume'

From 1969 to 1978 Jack Devanney served on the faculty of the Department of Ocean Engineering at M.I.T. where he taught courses in marine transportation and petroleum engineering. While at M.I.T. he was the Project Director of the widely emulated Georges Bank Petroleum Study and co-director of the Atlantic/Gulf Of Alaska Outer Continental Shelf Study for the Council on Environmental Quality. He is the author of two texts and some twenty papers. He holds a patent in the field of fluidized bed combustion. He has been a consultant to the United Nations, the World Bank, the National Academy of Sciences, the Office of Technology Assessment, the Organization of American States, the Federal Reserve Bank, and several Latin American governments.

From 1984 to 1990, Dr. Devanney was President and CEO of Majestic Shipping Corp, the largest independent American owner of very large tankers, carrying over 2% of all the oil imported into the United States in 1988 and 1989. In 1990, the Majestic fleet was valued at over 315 million dollars.

Between 1990 and 2005, Devanney was a Director of Hellespont Shipping Corp, owner of as many as 14 very large tankers. In 1999, under his direction as Program Manager, Hellespont instituted the largest large tanker newbuilding program in the world at the time, four 305,000 ton VLCC's at Samsung Heaving Industries, and four 442,000 ton ULCC's at Daewoo Shipbuilding and Marine Engineering. The latter are the only ships over 320,000 tons built in the last 20 years. These eight ships were delivered in 2001/2002. Dr. Devanney was responsible for all facets of this program: specs, financing, yard negotiations, supervision, and all major technical and commercial decisions.

In 2005, Jack Devanney retired and founded the Center for Tankship Excellence. Here is what he and his associate, Mike Kennedy, write about the "State of the Art".

State of the Art


Source HERE Thanks to our reader Barry English

For the last 20 years, Hellespont Shipping has operated six ULCC's built in the mid 1970's. In 1999, Hellespont embarked on an eight ship newbuilding program in Korea: four 300,000 ton VLCC's and four 440,000 ton ULCC's. These are the first ships that Hellespont has built in over 25 years. These ships are required to meet both ABS and LR rules.

Unfortunately, we found a number of areas where the Classification Society rules and yard standards have deteriorated drastically since the 70's, in some cases to imprudent levels.

We argue that the primary cause for this deterioration is the "direct computation down ratchet". In the absence of a meaningful guarantee, the yards are constantly and cleverly searching for ways to shave the rules.

Whenever any yard gets a relaxation in the rules, however risky, this new lower level becomes the standard. The class that approved the relaxation can't admit it was imprudent for both legal and commercial reasons. Other Classes feel they have to fall in line lest their ships become uncompetitively expensive. The rules ratchet down one level. The yards then compete away the saving and the process repeats itself. The individual changes generated by this process may not be large, but the cumulative effect can be massive. Over time, the yards are rewriting the rules, not Class Technical Committees.

Not only are Rules ships designed to handle only a unrealistically restrictive range of loading conditions, they are not designed to handle even the most likely damage scenario. Double hull tankers have a glaring weakness: their exposure to flooding of the ballast tanks when loaded. The idea of the double hull is that it's a buffer between the sea and the cargo. Whatever the merits of this idea, if it has any real purpose, you expect to use this buffer from time to time. Once the tanker fleet is converted to double hulls, it is nearly guaranteed that there will be multiple such floodings per year. Yet the Rules ignore this risk.

It is nuts that IMO Reg 25 and IMO Reg 16 Raking go to great length to require that the ship be able to withstand a whole range of flooding scenarios from a stability point of view, many of which scenarios the ship cannot withstand structurally.

Fatigue Life

The rule standard fatigue life is 20 years. Most tankers operate for 25 years or more. It has always puzzled us as to why Class would set an average time to failure less than the expected ship life. When Hellespont specified a 40 year fatigue life, some class software had to be recoded to accept the larger number. But an equally pressing problem is that fatigue life depends critically upon the trading pattern that was implicitly included in the specification. According to both LR and ABS, a ship trading in the North Atlantic has a very different fatigue life than one trading in Indian Ocean. In this case, the class software is almost certainly correct, at least in a qualitative sense. The most graphic example of this is the American flag tankers trading on the Alaska-West Coast route. In this very severe environment, some of these ships turned out to have fatigue lives of one or two trips. Closer to home for Hellespont, if a new VLCC trades Mongstad to Philadelphia rather than Ras Tanura-Yokohama, it's fatigue life is halved. The nominal 20 year life become 10.

Down Ratcheting explained

Here's the way the down ratchet works. A yard pressures a class to accept some cost saving relaxation of the rules by offering a "direct analysis" of the problem. Each yard has dozens of very sharp young naval architects who do nothing more than work on beating the rule. Once a contract is signed every kilogram of steel they save by so doing goes directly to the yard's bottom line. Inevitably some of these efforts are approved, however imprudently. Since the yard pays the newbuilding classification fees, in a commercial sense the yard is Class's customer. Occasionally, in this situation, the first rule of retailing applies.

As soon as that happens, the new lower requirement becomes the standard. The class involved can't admit it was imprudent to approve the change. If it did, it would have legal problems on all the ships that had been approved with the change; not to mention some very angry owners asking why did you approve this mess on my ships and then not on his; and not to mention an extremely angry yard who bid the ship under the "new" rule and finds out it has to build the ship under the "old" rule. (We know of at least one instance where a yard has threatened legal action against class for "changing the rules" in this manner.) The other classes have to fall in line because if they don't, their ships will be more expensive and they will lose owners. Having established a new lower standard, the yards then compete away the saving and must find new ways to save costs at that lower level, and the process repeats itself. Over time the ships get cheaper and lousier.

Welding

One of the authors inspected the Exxon Valdez in the drydock in San Diego seven months after the grounding. The real eye opener was not the damage, as extensive as it was, but the welding. Just about everywhere in the damaged areas the stiffener webs had pulled cleanly out of the welds leaving the welds on the plating. The welds were tiny. They looked like continuous tack welds. When I asked the Exxon superintendent who was showing me around if the welds were legal, he angrily nodded yes. This sort of failure absorbs almost no energy and may be a reason the Valdez rode so far up on Bligh Reef.

In the bad old days, the standard filet welds in a large tanker cargo tank had a throat thickness of 6.4 mm (9 mm leg length). Now much of the filet welding in the tank area has a required throat thickness of 3.2 to 4.0 mm. And Class allows the yards a 10% negative margin. (This is explicitly written into the IACS "Quality" Standards.) So often the actual weld is less than 3 mm throat. To expect any penetration at all with such welds is crazy talk. Those are the welds we saw in San Diego. Miniscule. And stupid. The yards can easily lay down 5 mm plus throat welds with a single pass. When Hellespont asked DSME to increase all welds in the ULCC cargo tank area to 5.3 mm throat - after signing the contract - the price was $44,000; and it cost the yard far less.

Whatever argument - probably nothing more than the down ratchet - led to the current weld sizes, it should be abandoned. Welds corrode much more rapidly than the other steel. And as the Valdez showed, these tiny welds fall apart on impact.

The Summary

We could go on and on. The down ratchet works everywhere. Rudder stock dimensions, steering gear torque, propeller blades, awkward and dangerous outfitting including pump room ventilation ducts that don't go to the pump room bottom, etc, etc.

We are not talking about losing 15 to 20% here. We are talking about losing 150 to 200% despite the much harsher design conditions associated with the diesel and its massive torque fluctuations. We know of three shaft coupling failures in new VLCC's, which means we can be sure there have been more. The repair yards tell us there is no chance of unscrewing the shaft couplings when the new V's come in for their first docking. They expect to have to drill them out since they all been over-torqued and badly fretted. And what does the owner gain for taking these massive risks? A few thousand dollars per ship which he will give back to the repair yard on the first docking. This is the down ratchet gone berserk. Table 15.1 shows one last example: main engine shaft couplings.

TABLE 15.1
Deterioration in Main Shaft Couplings, 1975 to 2001

- - - - - - - - - - - - - - - - - - - 1975 - - - - - - - - - - - - - - - - - 2000
Power - - - - - - - - - - - - 45,000 SHP - - - - - - - - - 44,640 BHP
RPM - - - - - - - - - - - - - - - - - 85 - - - - - - - - - - - - - - - 76
Engine Torque Pulse - - - - - - - nil - - - - - - - - - - - - - 80%
Flange Thickness - - - - - - - - 220 mm - - - - - - - - 140 mm
Coupling Bolts - - - 14 x 150 mm conical - - - - 12 x 95 mm reamer


Table 15.1 is an extreme case, but it is very difficult to find any scantling or parameter that is not at least 15% weaker on the new ships than the old. As a result, large tankers built to current Class rules are far less safe and less reliable vessels than those built 25 years ago. And the mid-70's ships as a group were not over-built. They were at best just good enough. Yet in the same period the potential liabilities associated with large tanker casualties have increased one hundred fold. It simply makes no sense. If the classification society system is to continue to exist, if it should be allowed to continue to exist, the Rules must be rewritten returning at a minimum to the standards of the 1970's. And the direct computation down ratchet must be eliminated.



End Note: by Merv Ritchie

It is important for those who live in the region of the North Coast of BC, those politicians, business persons and citizens, to listen to the words used by both sides and do their 'Due Diligence' to understand and comprehend just what the words mean. The site, linked above, provides a completely independent assessment of the Tankers available today to carry this Alberta Bitumen product out through Douglas Channel and much much more.

In this case "State of the Art" means a much lower quality than was previously available.

Another issue to consider is the statement;

The most graphic example of this is the American flag tankers trading on the Alaska-West Coast route. In this very severe environment, some of these ships turned out to have fatigue lives of one or two trips.

The current plan is to have approximately 250 trips per year from Kitimat through these waters. At this rate, if this analysis is anywhere close to accurate, we might expect to see a catastrophic spill in the first year of operation.