Case Studies

USNS John Ericsson Investigation Just hours after putting out to sea, the USNS John Ericsson sustained a rod bearing failure that left the starboard main engine crippled. Within 24 hours of receiving the call, Exponent engineers flew to Singapore for an extensive investigation. Optical and laser-based measurement techniques, designed specifically for this case, identified the cause of the failure as an improperly ground crankpin journal. We recommended adding a measurement to current grinding operations that would reduce the likelihood of future failures.

Lashing System Assessment and Sea-State Characterization Lashing failures aboard a large container ship sent 42 cargo containers over the side, resulting in losses of over 20 million dollars. Exponent's investigation included characterizing sea-states at the time of the accident, computing ship motions and accelerations, and modeling the lashing system. Using load estimates from this analysis and a design review of the lashing equipment, we identified failure modes for the current lashing system. Design alternatives are currently being pursued that will prevent these failure modes and reduce future container losses.

Exxon Valdez Exponent provided Exxon Corporation with a comprehensive assessment of hull damage resulting from the Exxon Valdez grounding incident. Engineers worked with Exxon to distinguish damage inflicted during the actual grounding from subsequent damage that occurred while the ship was lying on the reef. Over 30 engineers and technicians worked in the field to meet stringent time constraints. We developed a computer animation to graphically depict the damage to the 987-foot ship.

top