Evaluation of USCG Cutter Point Francis Propeller Strike on Right Whale Calf

Necropsy Field Number:  RKB-1424

James L. Wood

Lumatrex, Inc.

P. O. Box 510129

Melbourne Beach, FL  32951

321-956-1939

ABSTRACT

The propeller cuts detailed in the right whale necropsy report RKB-1424 are evaluated using new methods and computational tools recently developed by the author.  This accident was a witnessed event, and the level of documentation available regarding the physical characteristics and operation of the vessel involved make it uniquely suitable as a test case for demonstrating the range of information that can be revealed through the application of these techniques.  These methods use the position and size of propeller cuts visible in photographs for analyzing propeller cuts on marine mammals to determine the diameter of the propeller, the number of blades on the propeller, the approximate pitch of the propeller, the direction of propeller rotation, the relative approach of the vessel, the relative advance coefficient of the vessel, and changes in the relative speed of the vessel and/or the animal during the accident.  If the accident is a witnessed event and the speed of the vessel and rotation speed of the propeller are known, as is the case here, the actual speed of the animal at the point each cut is created can be calculated.  These methods can be applied to photographs of propeller cuts and scars on carcasses as well as on living animals.  Though a detailed explanation of the methods employed is beyond the scope of this evaluation, the results of this evaluation provide an interesting insight into the specifics of the accident and the capabilities of these new methods of analysis.

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