An appraisal is made of various mechanical means of transforming thermal power into hydraulic power, i.e., steam energy into ship thrust. The steam motor direct drive for a propeller makes a very attractive transmission. It is being explored in detail under a separate phase of the program. The torque converter development could result in substantially improved propulsion systems with either turbine or reciprocating steam prime movers. Other mechanical transmission schemes which were investigated include 1 Hydraulic split transmissions using both hydrokinetic and hydrostatic elements 2 Belt drives and 3 Variable pitch propellers. Hydrodynamic shear drives are being evaluated separately. Of the transmission currently thought feasible, the Fottinger transformer and the steam motor direct-drive offer the greatest incentive for further investigation.