Preliminary Crane Tests Show No Mechanical Failure

Preliminary tests conducted on the crane involved in a July 10 shipyard accident that killed six workers and injured six others at the National Steel & Shipbuilding Co. revealed no apparent mechanical failure, a company spokesman said. But a team of experts will begin a more exhaustive series of tests today.

The much-awaited tests, which will be conducted by various technical experts and supervised by the federal Occupational Safety and Health Administration, will examine the working order of the crane’s critical parts, Nassco spokesman Fred Hallett said. Normally, such thorough tests are required every four years for cranes certified in California, or whenever a crane is overhauled, modified or critical parts replaced.

According to Hallett, the crane involved in the accident underwent a four-year certification earlier this year.

“We will either discover an obvious mechanical problem, or barring that, we will have to assume that it was human error,” Hallett said.

A team of 10 investigators from Nassco workers’ unions, the company, the Navy and OSHA are looking into the cause of the accident, which occurred shortly after midnight. Crane operator Hugh Humphrey was transporting a steel mesh personnel basket loaded with 12 men when it plunged 30 feet to the deck of a Navy ship that was being overhauled.

Humphrey, 65, is on a paid leave of absence and has refused to discuss the accident.

The 12 workers were packed into the basket, which measured 6 by 4 feet, that was hooked to the crane’s whip line. The whip line, the smaller of the crane’s two cables was capable of lifting loads up to 10 tons. The load line, or main line, was rated to carry loads up to 54 tons.

Hallett said both lines will be tested at 110% capacity, and the whip line will be tested with a 12-ton load. Nassco officials said the combined weight of the personnel basket and workers was about 2 tons.

“After testing the lines at 110% capacity, we will take a weight of approximately 2 tons and put the crane through a simulation of movement as on the night of the accident,” Hallett said.

If the tests fail to indicate any mechanical problems with the crane, investigators will not strip the machine to check the parts.