Abstract: A marine propeller using the circulation control principle of blowing tantially over a Coanda surface at the trailing edge of each blade to develop high blade lift (thrust). Each blade has internal chambers and two blowing slots so that blowing is controllable for forward and for reverse thrust without reversing rotational direction of the propeller. This propeller is capable of generating much greater thrust and ship speed at lower RPM and noise levels than conventional propellers.

Abstract: An anechoic and decoupling coating for use on the surface of an underwater tructure for decoupling structural vibrations from the water and for absorbing waterborne acoustic waves directed toward the structure from an external source such as a sonar. The coating is an elastomeric matrix containing sealed air-filled cavities as well as random labyrinths of small water-filled passages running throughout and in open communication with a surface facing the water. Acoustic waves incident upon the water-facing surface cause time varying shear and bulk deformations within the matrix. As a result of these deformations, acoustic energy is dissipated by hysteretic damping of the elastomeric matrix as well as by viscosity due to water movement to and fro within the passages and into and out of the matrix.The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Abstract: A control surface design for submerged vehicles. The control surfaces are vably mounted or radially extending support members such that the wake created by the deflection of the control surfaces will not be transmitted to the propeller. The support members have a cross section that minimizes flow disturbances in the region of the propeller.