Hydrodynamic drag of drogues and sea anchors for drift control of freefloating buoys

Drift control for freefloating buoys can be achieved by employing easily packaged, deployable drogues at ocean depths where flow velocities are considerably less than surface currents. Various size sea anchors, cross-chute drogues, and triangular drogues were towed at the Naval Air Development Center´s 60-foot deep open water facility. Drag and lift forces on the drogues were measured at speeds up to one knot. Drogues were tested individually, in tandem with various spacings, and in clusters. Drag coefficients were determined for each drogue and combination. The results of a buoy drift control experiment, using drogues at depth to reduce the drift rate of buoys, conducted in an area south of Bermuda, are presented.