Perfect Pitch for Scallop Dredges

The Dredgemaster consists of: an acoustic receiver and computer in the wheel house, a hydrophone and sensors mounted on the dredge. Communication between the sensors and vessel is wireless. The system was developed in coordination with the scallop industry. A major partner in development was the FV Capt. Ryan from North Carolina USA. Over the last 13 months, the Captain Ryan has used the Dredgemaster. The most important parameters measured are: warp length, pitch angle and roll angle.

Warp length is measured on both dredges and has an accuracy better than 0.5m. Warp out is a major determinant of the dredge''s pitch angle (forward/backward angle). Pitch determines how well the dredge fishes. For example, the FV Capt. Ryan determined that the optimal pitch angle was 9°. Shooting just a mark too short would result in a 14° pitch and reduced fishing. Likewise, speed of the vessel greatly determines the dredge''s pitch.

The results of monitoring the dredges angle were clear. The FV Capt. Ryan set one dredge according to Notus''s readings. The other dredge was fished "the old way." Data was recorded over an entire day and Notus clearly demonstrated a 22% increase.

Roll angle is also monitored which instantly detects if the dredge flips during shooting. Other options available are: a club stick sensor, depth, dredge spread and temperature.