American Champion rolling gently in beam seas

Project Summary

During a transit from New Orleans to Seattle, via Panama Canal, the 200 ft catcher boat American Champion suffered an engine breakdown, causing it to drift for 7 hours, without power, off the coast of El Salvador.  During this period, a shipyard worker riding the boat was knocked over while getting up from his bunk and picking up his shoes.  He sued the ship owner for damages, blaming excessive ship motions, caused by the inability to control course during the breakdown.  The ship motions were reconstructed basis the actual experienced weather conditions and acceleration levels in various cabins were calculated.  As it turned out, the ship motions were rather mild with a maximum roll angle of only 6.3 deg, combined with a natural roll period of 12 s.  The corresponding acceleration levels were also small.   To illustrate the relatively small roll angle, a photo-realistic plot of the catcher boat rolling 6.3 deg in beam seas was made, using AutoCAD^®, see also above.

Scope of Work

The project scope included:

• Reconstructing most probable ship motions during period ship was drifting due to main engine failure;

• Analyzing sensitivity of sea state conditions and wave heading;

• Calculation of ship bound acceleration levels in the cabin where the alleged accident took place;

• Presenting the results in 3D plots, clearly illustrating the magnitude of ship motions to laypersons;

• Provision of comprehensive expert witness report.