COMMENT DOUBLE HULLS, DOUBLE BOTTOMS: BETTER WAIT FOR ALL THE EVIDENCE

William F. O'Keefe
Vice President and Chief Operating Officer
American Petroleum Institute

Some members of Congress say after the oil spills of the past year all new tankers should have double hulls.

They say the oil industry opposes double hull tankers for reasons of cost, and the industry broke a promise it made in the late 1970s to build double hull tankers to ship Alaskan oil. It is time to set the record straight.

The oil industry does not oppose double hulls, and a search of the Congressional Record for the past 17 years has failed to turn up any industry promise to build them.

LOOKING FOR ANSWERS

The oil industry is in search of answers on the issue of double hulls. For that reason, we are committed to support the conclusions of a soon to be completed National Academy of Sciences (NAS) study for the secretary of Transportation on tanker design.

Those in Congress who would mandate double hulls before the study is released are saying, in effect, that expert opinion and technical facts are irrelevant. That's similar to a judge pronouncing sentence while the evidence is still being presented-before the jury has a chance to render verdict.

We don't know what the verdict will be. Double bottoms could well be an effective way of reducing tanker spills. But there may be better ways. The final NAS report, due in November, should provide important answers.

The academy's blue ribbon committee, whose members include naval architects, university professors, and an environmentalist, is studying safety, engineering, economic, and environmental aspects of tanker design. That evaluation includes data on double bottom, double hull vessels in service during the past decade.

OTHER VESSEL DESIGNS

The NAS study isn't limited to weighing pros and cons of double hulls. Other designs are also being evaluated.

That includes evaluation of new technology on the horizon. For example, the Swedes have developed a technology that would use atmospheric pressure to prevent oil outflow when the hull of a tanker is punctured.

If Congress opts for double bottoms and double hulls now, before the study is completed, it would effectively freeze tanker design technology at present levels. That would be a fatal flaw. Progress is made by stimulating innovation, not by assuming today's technology is best.

Only a handful of studies has been conducted on the double bottom/double hull issue, most of them in the 1970s. The results were conflicting and inconclusive. One was based on several minor tanker groundings, another solely on the outflow of oil after an accident.

A 1974 review by the American Institute of Merchant Shipping warned, "While double bottoms in tankers might be helpful in some minor groundings they would offer no protection in more serious accidents ... and conceivably increase the amount of oil spilled."

These are concerns naval architects still share with the Coast Guard, International Maritime Organization, International Chamber of Shipping, and Center for Marine Conservation, all of which recognize that the double hull issue is far from clear-cut.

Withholding judgment for a few months until the secretary of Transportation has the information to make a proper decision is good public policy and will not cause any appreciable delays. Because of worldwide limits on shipyard capacity, it is highly unlikely that any tanker construction or retrofitting could begin during that short period.

RETROFITTING COSTLY

Retrofitting a large tanker with a double bottom is about as difficult as jacking up a 14 story office building to add a new full basement. Yet the mandate would require retrofitting on all 450 or so U.S. and foreign flag tankers and 1,800 tank barges that service American ports.

This is work that has never been attempted on a large scale. Only one double bottom has been retrofitted.

There is evidence that in some cases double bottoms or hulls could turn a controllable oil spill into an unmitigated disaster, making vessels harder to salvage or creating operational hazards that could cause the loss of human life as well as the sinking of the tanker with all its cargo.

These kinds of problems have been reported as probable causes for the loss of at least two vessels with double bottoms. More recently, the Exxon Valdez shipbuilders, in analyzing the Alaska spill, calculated that under three out of five accident scenarios the vessel might have sunk had it had a double bottom.

WHAT IT WOULD COST

While safety and the environment are certainly the biggest concerns in the double bottom/double hull issue, there is also the matter of cost.

The total retrofitting price tag for all existing tankers would be $16.6 billion, to say nothing of the added costs of new tanker and tank barge construction.

As Americans, we must ask whether it serves the nation's environmental goals to mandate the allocation of that much of our resources to a specific design when so many critical questions remain to be answered.

There are compelling reasons today for a "maybe" response to mandatory double hulls.

The point is that waiting a few months for the NAS study to be finished would make clear whether the right answer is yes or no.