Shear pin design for the fins on C-SCOUT

AuthorSearch for:
TypeTechnical Report
Series titleLaboratory Memorandum
SubjectC-SCOUT; AUV; shear pin; actuator; fin
AbstractShear pins are used to attach C-SCOUT's fins to their actuating motors, so if something impacts the fins, the shear pins will break and the fins will fall off, thereby protecting the motors from damage. An analysis of the strength of the existing Garolite shear pins showed that they will fail during normal operation. It is possible for the fins to break off when the vehicle speed exceeds 2 m/s. Exact failure speeds depend on the angle of attack of the fins. To fix the problem, re-design of the shear pins was attempted, basing the new shear pin strength on the load required to damage an actuator. It was found that the bearings in the actuator's gearbox will be damaged during normal operation, at speeds exceeding 1.3 m/s. Therefore, the motor will be damaged before the shear pins break, so creating stronger shear pins is not a solution that will protect the motors. Stronger fin actuators should be purchased. The potential for damage to the motors due to operational and impact loads should be considered when selecting a motor. Once new motors are selected, the method described in this report can be used to design appropriate shear pins. Until new actuators and shear pins are installed, C-SCOUT testing can proceed under a 2 m/s speed limit.
Publication date
PublisherNational Research Council Canada. Institute for Marine Dynamics
PlaceSt. John's, NL
AffiliationNRC Institute for Ocean Technology; National Research Council Canada
Peer reviewedNo
NRC number5271
NPARC number8896137
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Record identifiera9cade70-4241-48ea-886d-66811e96b262
Record created2009-04-22
Record modified2016-10-03
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