APPENDIX G
ACCIDENT SCENARIOS

The committee used the accident scenarios in this appendix to analyze the the salvage industry's response in today's environment to similar scenarios in the 1982 study (NRC, 1982). The committee conducted desktop audits and tabletop exercises, and contacted individuals and companies in the industry about equipment and timeliness, which the committee used to assess the salvage posture. The committee wishes to express its thanks to all who participated.

COLLISION AT THE ENTRANCE TO DELAWARE BAY

Technical Issues: Availability of Damage Control, Removal from Strand, Firefighting

While maneuvering to embark a pilot off Cape Henelopen, an inbound, fully laden crude oil tanker is struck within the cargo length by an outbound, laden, break-bulk cargo vessel. The tanker is carrying 122,000 deadweight tons (DWT) of crude oil (Libyan 37º API). The cargo ship is carrying 14,700 DWT of break-bulk cargo, with containers on deck covering the hatches. The situation unfolds at three levels of complexity.

No Fire, No Stranding

There is no fire, although the tanker leaks cargo oil through its breached hull. Both ships retain their propulsion capability, and damage to the cargo vessel is limited to the bow and forecastle. The cargo ship returns to port; the tanker anchors until the oil spillage is suppressed and the cargo is stabilized.

Both Ships Strand

Both ships strand following the collision, and neither ship is able to free itself. The grounding force of the tanker is about 2,000 tons (one foot aground). The tanker is leaking cargo through its breached hull; the cargo ship is not leaking bunkers. Both ships have ballasted down and either have kedged an anchor to seaward or have hooked up a tug astern to prevent broaching. There are no conditions that make this strand particularly hazardous. The bottom is hospitable and it is not a lee shore.

Both Ships Strand, Fire Occurs

Both ships strand following the collision, and fire breaks out on both ships; the spilled oil also is afire. Both ships are stranded beyond their ability to refloat themselves. The cargo ship contains cargo that may be dangerous or may produce a dangerous byproduct when burned.



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A Reassessment of the Marine Salvage Posture of the United States APPENDIX G ACCIDENT SCENARIOS The committee used the accident scenarios in this appendix to analyze the the salvage industry's response in today's environment to similar scenarios in the 1982 study (NRC, 1982). The committee conducted desktop audits and tabletop exercises, and contacted individuals and companies in the industry about equipment and timeliness, which the committee used to assess the salvage posture. The committee wishes to express its thanks to all who participated. COLLISION AT THE ENTRANCE TO DELAWARE BAY Technical Issues: Availability of Damage Control, Removal from Strand, Firefighting While maneuvering to embark a pilot off Cape Henelopen, an inbound, fully laden crude oil tanker is struck within the cargo length by an outbound, laden, break-bulk cargo vessel. The tanker is carrying 122,000 deadweight tons (DWT) of crude oil (Libyan 37º API). The cargo ship is carrying 14,700 DWT of break-bulk cargo, with containers on deck covering the hatches. The situation unfolds at three levels of complexity. No Fire, No Stranding There is no fire, although the tanker leaks cargo oil through its breached hull. Both ships retain their propulsion capability, and damage to the cargo vessel is limited to the bow and forecastle. The cargo ship returns to port; the tanker anchors until the oil spillage is suppressed and the cargo is stabilized. Both Ships Strand Both ships strand following the collision, and neither ship is able to free itself. The grounding force of the tanker is about 2,000 tons (one foot aground). The tanker is leaking cargo through its breached hull; the cargo ship is not leaking bunkers. Both ships have ballasted down and either have kedged an anchor to seaward or have hooked up a tug astern to prevent broaching. There are no conditions that make this strand particularly hazardous. The bottom is hospitable and it is not a lee shore. Both Ships Strand, Fire Occurs Both ships strand following the collision, and fire breaks out on both ships; the spilled oil also is afire. Both ships are stranded beyond their ability to refloat themselves. The cargo ship contains cargo that may be dangerous or may produce a dangerous byproduct when burned.

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A Reassessment of the Marine Salvage Posture of the United States CHEMICAL BARGE STRANDED OFF PUERTO RICO Technical Issues: Salvage in Presence of Hazardous Cargo, Underwater Salvage, Refloating A chemical barge, fully laden with a hazardous polluting substance and inbound to San Juan, Puerto Rico, breaks away from its tow off Isla de Cabras. The barge is double-bottomed, 300 feet long by 43.5 feet, with a depth of 18 feet. It contains 30,000 barrels of cargo in a 5-by-2 tank arrangement. The bottom is hard and the wind is onshore. The situation unfolds at two levels of complexity. Strand The barge grounds on a 12-foot pinnacle. The integral cargo tanks are intact. The grounding force is approximately 800 tons; however, the barge cannot be pulled off due to the danger of tearing open the remainder of the bottom. The barge is equipped with pumps, but the generator that drives them is disabled. Founder The barge is dragged over the pinnacle, is torn extensively, and sinks in 50 feet of water. The nature of the cargo is such that it must be removed and promptly. There is no leakage of cargo, but all double-bottom tanks and the after-rake compartment are breached. The wing tanks are intact. The barge is upright on a relatively flat, hard bottom with cargo vent valves closed. The underwater visibility is 10 to 20 feet, and all cargo pumping systems, piping, and valves are sound and in operating condition. The pump room is accessible to divers. LARGE TANKER STRANDED IN THE FLORIDA STRAITS Technical Issues: Rescue Towing, Refloating, Jettisoning En route from North Africa to a deepwater port in the Gulf of Mexico, a fully laden 250,000-DWT Very Large Crude Carrier (VLCC) loses power off Sombrero Key in the Florida Straits. She is carrying a full cargo of North African crude oil (44 º API). The foreign-flag VLCC is owned by a major U.S. oil company. The situation unfolds at two levels of complexity. Mechanical Breakdown The VLCC drifts toward shore. If she does not obtain a rescue tow, she ultimately will strand at Delta Shoal. The ship is in a head current of 1.5 to 3 knots, with a 25-knot south-southeast wind. Delta Shoal is 34 miles northeast of the ship when the ship loses power; the overall drift period to Delta Shoal, given the current and wind conditions, is 19 hours. Stranding A tug fails to arrive in time, and the ship drifts and strands, with light pollution. The grounding force is 27,000 tons.

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A Reassessment of the Marine Salvage Posture of the United States CASCO BAY TANKER STRANDING Technical Issues: Lightering, Rescue Towing, Safe Haven, Damage Stability Bound for Portland, Maine, from the Caribbean, a 21,000-DWT product tanker carrying a full load of distillate (34º API) strands on a rock off Portland Head Light in Casco Bay, Maine. The tanker is foreign owned and registered. It is fall, and the weather is deteriorating. The situation unfolds at two levels of complexity. Strand, Refloat The ship comes off the ground on the incoming tide. The ship is capable of navigation but is leaking. The Coast Guard refuses entry into the port until the ship has been lightered and is not a pollution hazard. Strand and Refloat, with Damage The propeller is damaged in the strand such that the vessel is incapable of navigation. The ship is not expected to come off the strand on the incoming fide, which will occur six hours after the initial notification of the stranding. The estimated remaining ground force is 1,350 tons. Major pollution is thought to be from ship's bunkers. Seas are 4 feet, choppy, and building. The weather forecast calls for winds and seas to build for 19 hours, with a northeaster continuing for 48 hours. The ship is leaking from three ruptured center tanks and possibly from the engine room double-bottom bunker tanks. COLLIER STRANDING OFF NORFOLK Technical Issues: Refloating, Cargo Offloading, Heavy-lift Capability Two scenarios are possible. In the first, a number of bulk carriers are anchored in Anchorage L-C to the west of Thimble Shoals Channel waiting to load coal in Norfolk, Virginia. A sudden and fierce summer squall causes one of the colliers to drag its anchor to the east. She is light and strands on rip rap on the eastern bridge island of the Thimble Shoals Channel. The double bottom is flooded to the extent that the ship is about 12,000 tons aground. The ship is projecting into the channel but due to channel width does not block the channel. The second scenario assumes that the bulk carrier is loaded, loses steering, and strands in the same position. ROLL-ON/ROLL-OFF SHIP CARGO SHIFT Technical Issues: Rescue Towing, Damage Stability A roll-on/roll-off (RO/RO) ship carrying heavy vehicles and containers under charter to the Military Sealift Command is caught off Cape Hatteras in heavy weather 40-knot winds from the northeast with 16-foot waves. The ship loses power, is unable to maintain its heading, and takes heavy seas broadside. The heavy rolling causes several vehicles to break loose and eventually puncture the ship. The flooding rate is slow but steady. The weather conditions and the danger of further cargo shifts preclude the crew from taking action to control the flooding. The ship is 20 miles east of Cape Hatteras and 125 miles from the entrance to Chesapeake Bay. If a response cannot be marshalled within 12 hours, the chance of saving the ship is less than 50/50.

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A Reassessment of the Marine Salvage Posture of the United States GREAT LAKES ORE CARRIER Technical Issues: Rescue Towing, Portable Pumping Capability, Damage Stability In the late fall, a Great Lakes bulk carrier loaded with 25,000 tons of iron ore is caught in a severe storm in Lake Superior, near the U.S./Canada border. She suffers severe structural damage, such that the longitudinal strength of the ship is jeopardized. Weather is overcast in rain, winds are 35 to 50 knots, and waves are 12 to 15 feet. The ship is experiencing flooding and has no motive power. COLLISION OF TANKER AND BULK GRAIN CARRIER OFF GALVESTON Technical Issues: Firefighting (with Inerting), Rescue Tow, Lightering A bulk carrier (U.S. flag and cargo) hits a foreign-flag tanker (Far East owner, U.S. cargo) 2 miles off Galveston, Texas. The bulk carrier's bow penetrates the tanker in the midship tank. Fires on both ships cause considerable structural damage. The tanker pump room, emergency power, and piping are intact. The 150,000 DWT tanker is loaded with North African crude; the 70,000 DWT bulk carrier is loaded with grain for Europe. The tanker has neither an inert gas system nor a ship's drawing or stability manual. Fires prevent access to both ships' bows for anchoring. Crude oil is leaking and partially burning from the No. I starboard wing tank and the No. 3 center tank. LOSS OF PROPULSION ON VLCC IN OPEN SEAS Technical Issues: Rescue Towing A 300,000-DWT VLCC (U.S. flag and cargo) loses propulsion while inbound from the Caribbean through the Yucatan Straits to the Louisiana Offshore Oil Port (LOOP). An approaching hurricane threatens to drive the ship toward the northwest shore of the Yucatan Peninsula or into the Bay of Campeche. Only the main propulsion engines are affected; emergency power and other facilities are operable. The casualty site is about 190 miles south-southeast of LOOP, 425 miles north-northeast of Merida, and 600 miles west-northwest of Key West. The hurricane is 575 miles southeast of the VLCC, moving north-northwest at 15 knots, and can veer east or west. Winds are at 40 knots from the northeast, waves at 16 feet from the northeast, the current is easterly at 2 to 4 knots, and the forecast is uncertain. Even with major veering of the hurricane, the VLCC can be expected to hit Yucatan in about 70 hours. Although the ship has power, its anchors are useless because the water is over 6,000-feet deep. TANKER RAMMING OF UNMANNED PLATFORM Technical Issues: Firefighting, Rescue Towing, Rig Salvage A product tanker (U.S. flag and cargo) rams an unmanned six-well oil and gas production platform 70 miles south of Morgan City, Louisiana. The tanker bow is badly damaged and an empty wing tank is ruptured, but the rest of the cargo space is intact. Fire breaks out due to oil and gas escaping from production equipment and pipeline. The ship loses steering and the forepeak is inaccessible due to fire and

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A Reassessment of the Marine Salvage Posture of the United States inoperable due to damage. The platform emergency shutdown system fails on at least one well, so oil continues to feed the fire. The tanker is unable to separate from the platform for fear of increasing the damage. COLLISION OF BENZENE TANKER AND CONTAINER SHIP WITH NUCLEAR MATERIAL ABOARD Technical Issues: Salvage in Presence of Hazardous Materials, Safe Haven, Cargo Offloading, Firefighting A "drug-store" tanker (U.S. flag and cargo) is struck by a U.S.-flag container ship that has, among other cargo, one 50-ton container of spent nuclear fuel. The tanker is holed in a benzene cargo tank and fire breaks out on both ships. The casualty occurs in the open sea, 200 miles south of Mobile, Alabama. Both ships bows are inaccessible due to fire; the container ship forepeak machinery and windlasses are inoperable. The container ship is flooding. LOSS OF STEERING ON AMMONIA TANKER, GROUNDED OFF APALACHICOLA Technical Issues: Salvage in Presence of Hazardous Materials, Refloating, Lightering, Rescue Tow A 30,000-DWT anhydrous ammonia tanker has a steering failure off the coast between Tampa and Panama City, Florida. She is driven aground in shallow waters off Apalachicola, bow first at midtide. The double bottom is ruptured forward; cargo tanks are intact but subject to increased heat transfer from water in the hold and potential damage from motion induced by seas. Condition of onboard protective clothing and breathing gear is questionable. The relief valves on the tanks are set at 10 pounds per square inch. The ground reaction on the strand is approximately 1,500 tons at high tide; the ship must be lightened by about 3,000 tons to break her loose. The wind is 20 knots with waves to 6 feet, and the forecast is for worsening weather conditions. TANKER RAMMING OF JACK-UP MOBILE DRILLING RIG NEAR SHIPPING FAIRWAY SOUTH OF LAKE CHARLES Technical Issues: Firefighting, Inerting Equipment, Lightering, Multiple Casualty Salvage A 200,000-DWT tanker strays from the shipping fairway on a foggy night and rams a three-leg, jack-up mobile drilling rig with 400-foot water depth capability. Due to the summer hurricane season, the jack-up deck is set to have 51-foot clearance above the sea level. The tanker's bow goes beneath the jack-up deck and damages the legs. Primary tanker damage is to the forecastle deck and machinery and to the forepeak and bulbous bow. The forepeak tank is ruptured but all cargo tank piping is intact. The drill rig damage is major, although the legs have some residual strength. The drill string is ruptured, but high enough above the seafloor blowout preventer that oil flow can be stopped by diver operation of the blowout preventer. There is no fire, because no free oil was present before metal-to-metal motion was stopped. There is the potential of a gas blowout, and spilled oil is polluting nearby fishing grounds.

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A Reassessment of the Marine Salvage Posture of the United States TANKER BREAKS LOOSE FROM MOORING Technical Issues: Rescue Tow, Lightering, Damage Stability, Jettisoning A 100,000-DWT crude tanker breaks loose from its mooring off Oahu, Hawaii, owing to failure of mooring attachments. Winds are 25 knots and there is heavy rain. Derangement of the propulsion plant prevents lighting off the main engine; emergency power is available initially. The ship strands in a broached condition and is moving slightly on the strand. The ship is 12,000 tons aground and will go further aground within 36 hours, suffering major structural damage. Tugs are unable to pull the ship from the strand. Weather is changing to favorable conditions. RO/RO SHIP RAMS PLATFORM IN COOK INLET Technical Issues: Rescue Tow, Heavy Lift, Internal Transfer of Ballast, Salvage in Ice A RO/RO general cargo ship inbound from Seattle to Anchorage is caught and stopped by ice flowing at the top of the tide in Cook Inlet, Alaska, and is swept into an oil platform at night. The ship strikes the platform beam, and the platform's several projections puncture the ship's side. The engine room and machinery spaces are flooded and the ship is expected to heel severely in three to four hours. There is no pollution threat. The ship is swept free of the platform but is unable to maneuver. TANKER AND CONTAINER SHIP COLLIDE OFF STRAIT OF JUAN DE FUCA Technical Issues: Rescue Towing, Lightering, Damage Stability, Multiple Response, Safe Haven Two inbound ships, a 35,000-DWT container ship bound for Vancouver, British Columbia, and a 125,000-DWT crude tanker inbound for Puget Sound, collide 50 miles off the entrance to the Strait of Juan de Fuca. An engine room fire aboard the tanker has distracted the crew, contributing to the accident, and the fire rapidly flames out of control with resulting loss of propulsion. The crew abandons the ship. The container ship, badly damaged, can maneuver but may need rescue towing to make it into port. The damage to the tanker is confined mostly forward of the collision bulkhead. The fire in the engine room burns out. The tanker has been refused entry into a port until the first cargo hold aft of the collision bulkhead is removed at sea. TANKER AND FISH PROCESSOR COLLIDE IN SHELIK OF STRAIT Technical Issues: Salvage in Presence of Hazardous Materials, Ship to Ship Transfer, Safe Havens A 930-foot liquified natural gas (LNG) tanker with 127,000 cubic meters of cargo, outbound from Nikiski, Alaska, to Japan, rams a 600- to 700-foot Korean-flag fish processor on station off Kodiak Island, Alaska. The fish processor is holed in two cargo holds; the ammonia system is damaged and leaking, forcing all hands on deck for evacuation. The captain beaches the fish processor deliberately in Wide Bay. The LNG ship is holed in the bow, but no cargo tanks are leaking. The captain is unwilling to proceed with the voyage, and the vessel will have to transfer its cargo to another LNG tanker. The transfer should take place in protected waters, but the state of Alaska may be reluctant to allow the ship to return.

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A Reassessment of the Marine Salvage Posture of the United States STRUCTURAL FAILURE ON ANHYDROUS AMMONIA CARRIER IN THE COLUMBIA RIVER Technical Issues: Rescue Towing, Salvage in Presence of Hazardous Cargo, Refloating A ship carrying anhydrous ammonia, 630-feet long with a 90-foot beam and 31-foot draft, has a structural failure and beaches on the Columbia River bar. Spring flood tides generating a 9-knot current and heavy seas combine to cause waves to break over the bar, and the ship is damaged. The potential for an ammonia cloud poses a threat to Astoria, Oregon. The main switchboard of the vessel has been shorted out, causing the casualty. STRUCTURAL DAMAGE TO A PRODUCT TANKER IN SAN FRANCISCO BAY Technical Issues: Rescue Towing, Safe Haven, Salvage in Presence of Hazardous Cargo, Underwater Salvage A 28,000-DWT chemical tanker loaded with benzene and bound from San Francisco to the East Coast is overstressed due to improper loading. Passing over the bar at the harbor entrance, a crack opens athwartship on the main deck. The master attempts to turn around at the channel's edge, the crack proliferates, and the tanker breaks in two. About 1,000 tons of benzene are released into the water. The stern section is unstable and sinks in 40 feet of water, while the bow section, containing some 10,000 tons of benzene in four tanks, remains adrift. FIRE AND EXPLOSION ON CHEMICAL TANKER OFF LONG BEACH Technical Issues: Firefighting, Damage Stability, Lightering, Heavy Lift A 35,000-DWT product tanker grounds on the breakwater at the entrance to Long Beach, California, catches fire, and explodes on a smoggy summer day. At least one or more of the forward tanks has been ruptured. The ship is fast to the breakwater. FIRE ON A TANKER OFF VALDEZ Technical Issues: Rescue Towing, Firefighting A 225,000-DWT tanker departs Valdez, Alaska, assisted by three 7,000-horsepower tugs. The tugs are equipped with gear for rescue towing and firefighting. Fire breaks out in the engine room, fed by a broken lube oil line, forcing evacuation of the engine and control rooms and the release of carbon dioxide into the engine room. The escort tug has left to return to port. The ship begins to lose steering and swing into the trough. The use of the ship's anchors is attempted unsuccessfully. The fire is confined to the engine room through inerting of the pump room and cofferdams.

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A Reassessment of the Marine Salvage Posture of the United States TANKER STRANDING OFF EAST COAST1 Technical Issues: Jettisoning, Damage Stability, Refloating An 80,000-DWT tanker is en route from Pajaritos, Mexico, to a refinery on the Delaware River with a cargo of 78,500 tons of Isthmus crude oil. The ship experiences a mechanical problem with its gyro compass and grounds in 35 feet of water near Diamond Shoal. The ship runs head-on into the shoal at 15 knots and comes to rest with 45 percent of her length resting on the sand. The hull remains intact and there are no leaks. A hurricane is approaching and will arrive within 16 hours. The increasing force of the winds and waves is expected to force the ship further onto the shoal, with eventual structural failure due to very high bending stresses. Internal transfer of the cargo will not refloat the vessel, and lightering is not possible due the deteriorating weather and distance from lightering resources. The discharge of 1,700 tons of cargo will allow the ship to refloat and continue its voyage. Delay will result in the ship being damaged beyond the point where she and her cargo can be saved. 1   This scenario was not used in the 1982 study and is included here to draw attention to the issue of jettisoning. While the incident unfolds on the East Coast, the scenario could apply to any coast or region.