Abstract: A propeller shroud or nozzle, made with airfoil section of high lift to drag ratio, increases thrust, speed and efficiency of a fixed or controllable pitch propeller operating inside the shroud. Shroud section is designed with continuously curved inside and outside surface to create maximum lift and minimum drag. For the larger propellers used on ships, and for lower cost of construction, shroud is fabricated using plates of steel and stainless steel or other suitable material, built as a number of straight airfoil segments forming a polygon approximating circular ring. Low shroud drag makes possible improving thrust and speed of vessels, even when operating at high speed, compared to optimally designed propeller without the shroud.

Abstract: A skeg unit mounted on a raked barge stern counter is a box lattice structure including an athwartships row of upright generally parallel vanes having their upper ends connected by an athwartships upper horizontal tie plate and their lower ends connected by a horizontal lower tie plate. The box lattice structure is mounted to the barge stern counter by struts spaced athwartships of the barge of a length to locate the upper tie plate below the loaded waterline of the barge. The vanes are of airfoil cross section and the outboard vanes are toed out. The horizontal tie plates are of airfoil cross section and have negative angles of incidence, the negative angle of incidence of the upper tie plate being greater than the negative angle of incidence of the lower tie plate.

Abstract: A row of dagger skegs projects downward from the aft portion of the raked counter of a nonpowered, nonsteered barge hull at each side of the longitudinal center line of the hull for stabilizing the barge directionally when towed by a towline trailing a towboat. The upright skegs are of airfoil cross section, and they are tapered downwardly. The leading edge of each skeg, which extends over the major portion of the height of the skeg, is substantially vertical and is spaced rearwardly from the stern counter. The lower end portions of adjacent skegs can be connected by an elongated horizontal bridging member which also is of airfoil cross section having a cambered upper side and a negative angle of incidence.

Abstract: A row of dagger skegs projects downward from the aft portion of the raked counter of a nonpowered, nonsteered barge hull at each side of the longitudinal center line of the hull for stabilizing the barge directionally when towed by a towline trailing a towboat. The upright skegs are of airfoil cross section, and they are tapered downwardly. The leading edge of each skeg, which extends over the major portion of the height of the skeg, is substantially vertical and is spaced rearwardly from the stern counter. The lower end portions of adjacent skegs can be connected by an elongated horizontal bridging member which also is of airfoil cross section having a cambered upper side and a negative angle of incidence.