Abstract: A marine propulsion assembly comprises or consists of a marine engine, a pair of parallel laterally spaced propeller shafts and a pair of marine propellers with one of the propeller fixed to each of the shafts for rotation. Each of the propellers includes a hub and four equally spaced blades and wherein the hub has a forward portion having the shape of a frustum of a cone with a decreasing radius from a forward edge thereof to the middle of the hub and a rear or second continuous portion having the shape of a frustum of a cone with an increasing radius from the middle of the hub to the rear of the hub. The bases or larger ends of the frustums are of equal size as are the tops of the frustums. In addition, each of the blades has a complex concave shape.

Abstract: A marine propulsion assembly comprises or consists of a marine engine, a pair of parallel laterally spaced propeller shafts and a pair of marine propellers with one of the propeller fixed to each of the shafts for rotation. Each of the propellers includes a hub and four equally spaced blades and wherein the hub has a forward portion having the shape of a frustum of a cone with a decreasing radius from a forward edge thereof to the middle of the hub and a rear or second continuous portion having the shape of a frustum of a cone with an increasing radius from the middle of the hub to the rear of the hub. The bases or larger ends of the frustums are of equal size as are the tops of the frustums.