API CONFERENCE HIGHLIGHTS TANKER DESIGNS, SPILL PLANS

Independent tanker owners say double hulled tankers are their least preferred option for reducing oil spills.

That's the conclusion of a survey of its members by International Association of Independent Tanker Owners (intertanko), Oslo.

Philip Embiricos, vice-president of Embiricos Shipping Agency, presented Intertanko's findings at an American Petroleum Institute conference on tanker safety.

API said its Washington, D.C., meeting was the first public forum on tanker design. It showcased 24 concepts, ranging from new tanker designs to methods of limiting spills.

INTERTANKO SURVEY

Intertanko members' first preference is Marpol design tankers with hydrostatic balance systems, followed by double sided tankers with hydrostatic balance, the survey showed.

Completely double hulled tankers ranked last among 10 options.

Embiricos said future tanker design will use void or ballast spaces to protect against collision or grounding and hydrostatic balance of vacuum methods to prevent outflow if a tanker is damaged.

Legislators should be cautious about requiring double bottom/double hull tankers due to environmental and safety considerations, he warned.

Vessels with more tanks have added corrosion problems, must be inspected more frequently, and the ballast tanks can collect gas and explode, Embiricos said.

DESIGNS, DOUBLE HULLS

Here are some of the papers on tanker design presented at the conference:

Pyramid Systems Inc., Sacramento, detailed plans for a welded core pyramidal truss panel for double skin tank barges.

Columbia Research Corp., Annapolis, presented a paper on structural designs resistant to damage from grounding or collision.

Tangent International Corp., Grants Pass, Ore., proposed a method of subdividing existing tanks in tankers to lessen the chance of a major spill, but with special bulkhead gates to ease loading and unloading.

Engineering Computer Optecnomics Inc., Annapolis, outlined a plan for building double hulled tankers without a loss of cargo carrying capacity.

Wartsila Marine Inc., Vancouver, proposed a design for a double hull shuttle tanker carrying its own oil spill recovery system.

Mitsubishi Heavy Industries Ltd. outlined a plan for a double sided tanker with a hydrostatic pressure system to limit spills from a rip in the single hulled bottom.

Shell International Marine Ltd., London, also offered a double sided design, with the side ballast tanks extending lower in the water than the center cargo tanks.

SPILL PREVENTION, RESPONSE

API conferees also presented these papers on oil spill prevention and response:

E.I. Du Pont de Nemours & Co. unveiled a composite liner system for cargo tanks to prevent spillage if the outer metal hull is penetrated.

M.H. Systems, Del Mar, Calif., discussed a retrofit system for tankers to limit spillage to the volume below the line of rupture.

Swedish National Maritime Administration proposed a system for pressure/vacuum relief valves to minimize escape of oil from damaged cargo tanks.

Automated Response Systems Inc., Sausalito, Calif., discussed its proposal for a water filled buffer bag retrofitted in the bottom of cargo tanks.

Ocean Clean Inc. Huntington Beach, Calif., disclosed plans for a ship mounted system to recover oil and store it in a flexible, floating bag.

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