5. Propeller project

A propeller project is the result of discussions between a ménage à trois: the naval architect defines the hull shapes, the engine builder the characteristics of the engine he proposes, and the propeller specialist, the poor relation of the trio, must adapt to the constraints imposed by the other two. The degree of complexity involved in calculating a propeller depends on the vessel or craft it is to propel. In the case of a propeller for an outboard motor designed to propel a pleasure craft, its characteristics are taken from a catalog of models according to the motor's power and the dimensions of the boat to be propelled. In the case of a self-propelled barge, its characteristics are also determined from the engine and tonnage of the barge, using simple calculation methods based on the curves given in paragraph