Vessel Returns to Point Loma : Navy Vehicle Takes a Plunge to a Record Depth

The Sea Cliff, one of two submergence vehicles owned by the U.S. Navy, returned to its home port Friday after setting a record by diving to 20,000 feet off Guatemala’s Pacific Coast.

The 31-foot, 29-ton, three-man craft returned aboard the deep submergence support ship Point Loma after spending more than a month at sea. Lt. Cmdr. Richard B. Williams, who commanded the craft, described the ocean descent on March 10 as “an uneventful dive.”

Navy officials said it was the first time that the Sea Cliff had dived to the depth it was designed for. Previously, the deepest dive for the ship, which is known as a Navy Deep Submergence Vehicle, had been 15,000 feet. A sister ship, the Turtle, was designed to dive to a maximum depth of 10,000 feet.

Williams said the dive took place in the 23,000-foot Middle America Trench. In addition to Williams, the crew on the record dive consisted of Lt. Alan Mason, who piloted the vehicle, and Chief Petty Officer David Atchinson, the co-pilot.

The crew spent 14 hours in the water on the day of the record dive, but only 90 minutes at 20,000 feet. The Sea Cliff can spend 16 hours at that depth. But Williams jokingly said that an hour at that depth is usually enough because “spending 16 hours crammed in a tight space with two other guys can test your tolerance.”

A crew of 14 enlisted men and three officers man the Sea Cliff, and every man gets to dive in the craft, said Williams.

The deepest ocean descent on record occurred in 1960, when the U.S. Navy Bathyscaph Trieste dove to 35,000 feet. However, Williams said the Trieste was expensive to operate, maintain and transport. The Sea Cliff is less expensive to operate and equipped with newer technology. The craft can be transported by highway, rail, plane or ship and can make repetitive dives, said Williams.

In June, the Sea Cliff made 61 dives off San Clemente Island to retrieve a Marine Corps helicopter that had crashed in the ocean while carrying a 23,000-pound truck and a crew of four. Williams said that 80 percent of the aircraft was recovered, in addition to the truck and the bodies. The ship uses two mechanical arms and a hook controlled from inside to retrieve objects from the ocean floor.

The lure of setting a record dive was not the only motivating factor, said Williams. National pride was also at stake. Williams said that the French and Japanese are testing similar vehicles that have the potential to dive to 20,000 feet.

“America’s already there, and the French and Japanese are following,” said a grinning Williams.

Navy officials said that the Sea Cliff’s operating depth of 20,000 feet gives them the capability to reach 98% of the ocean floor.