A new barge on its maiden voyage suffered a structural failure crippling her in a busy cargo area of San Francisco Bay. Salvagers needed to pump out much of the 2,600 tons of Canadian sand in the Eva Joan's cargo hold quickly without damaging the cracked vessel further and obscuring evidence that would help determine the cause of the failure. The 250-foot-long barge had folded nearly in half and was left stuck in 60-foot water, kept partially afloat by water tight compartments fore and aft.
Protecting the damaged hull and a strong tidal current ruled out using the large dredge pumps and clamshell bucket customarily used on projects like this. Instead, two modest-sized industrial pumps normally used in a less punishing operating environment were applied to suck the sand out as slurry.
"They didn't have dredge pumps sized to fit the application," recalls Fred Kesich, chief engineer with Pac Machine, an ITT Flygt dealer. "We had in stock two ITT Flygt Model 2670 submersible pumps we felt were durable enough for the task. Both have specially sealed impeller and motor bearings that are inherently protected against dirty, often abrasive environments. Although not the ideal application in this case, the 27-hp Model 2670 units at least offered a viable alternative to dredge pumps or clawing the sand out with a clamshell bucket."
Underwater Resources put four commercial divers on the job. The pumps were hung from cranes on either end of a 60Œ~120Œ derrick barge and went to work.
In about two weeks, the barge rose enough for a tow. It inched ashore and went aground again about half a mile from shore. At that point, the clamshell bucket could be used to empty enough additional sand for the barge to make it to a marina in Alameda.
"We had a good crew who worked 620-plus hours, from the initial underwater survey to development of the plan with a naval architect. Much of it was in 12-hour days," said Dean Moore, an engineer with Underwater Resources.
"Diving teams in that part of the Bay are pretty much limited to a tidal current of less than 1.5 knots," he said. "We were very pleased to complete the job without any lost-time injuries. Pac Machine proved to be very responsive and the Flygt pumps operated very well."