Mast removal begins today

U.S. Pacific Fleet Public Affairs

PEARL HARBOR (July 20, 2001) -- Ocean Hercules, the vessel contracted by the Navy to prepare Ehime Maru for this summer's recovery operation, has begun the process to remove the ship's center mast.

The center mast must be removed because it would obstruct the spreader assembly or lower frame that will be placed immediately above Ehime Maru.

Ocean Hercules' crew, using the remotely operated vehicle (ROV) Phoenix III, will cut the mast off using a shaped charge -- about 1.5 pounds of C-4 explosive placed at the base of the mast in a U-shaped linear charge that directs the explosive energy inward toward the mast. The small charge was considered the safest and most controllable method to remove the mast. It is a technology that has been well researched and routinely used in the offshore oil industry for many years.

An ROV will connect a lifting wire to the mast so a crane or winch can lift it from the sea floor to the ocean surface and then onto the deck of the ship. Mast recovery may occur with Ocean Hercules or Rockwater 2 early next month. The decision will be based on the on-going work schedule of Ocean Hercules.

The mast removal is part of the on-going preparation on Ehime Maru before the arrival of Rockwater 2, which will try to lift the ship about 100 feet off the ocean floor and move it while still submerged to shallower water about a mile south of Honolulu International Airport's Reef Runway. When it is stabilized at a depth of about 115 feet, divers will search all safely accessible areas to recover missing crewmembers, personal effects and certain unique characteristics of the ship, such as its nameplate and anchor, for a possible memorial. Hazardous materials such as fuel oil and freon cylinders will also be removed to the maximum extent practicable.

Ocean Hercules' prep work also includes using Phoenix III to attempt to clear or secure Ehime Maru's decks of any fishing long lines and other obstacles that might impact the marine environment. It will also clear away the ocean floor adjacent to the Ehime Maru where the lifting plates will be pulled under the ship. This clearing operation will provide a better angle of approach for pulling the two lifting plates under the vessel's hull.

There is the potential, however unlikely, that some diesel fuel -- a light, refined petroleum product that quickly evaporates within hours or days -- may be released during the mast-removal operation. Because of that, the Navy will deploy a skimmer with two 300-foot containment booms and two tow boats. There will also be two helicopters overhead to inspect the area and direct the skimmer to the location of any potential diesel fuel release.
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Revised 7/26/01 at 1:46 p.m. (HST)