Abstract: An AC marine propulsion system which provides a constant continuous rated horsepower availability at the standard rated engine RPM, over the full useful operating range of the propeller. A prime mover diesel engine is operated at its continuous rated speed to provide for maximum fuel efficiency. An alternator connected to the prime mover is driven at a speed which is higher than the standard rated alternator speed, thus producing higher than standard rated voltage and frequency. The combination of prime mover and alternator provides for an optimum system mass to power ratio. An AC motor is coupled through a gearbox to a fixed pitch propeller system. A frequency converter is dispsoed between the alternator and AC motor. Propeller RPM is controlled by changing the frequency of the voltage supplied to the AC motor.

Abstract: An improved process is disclosed for splicing metal shafts, in which a pair of shafts (10, 12 or 44, 46) having transverse end surfaces (30, 32 or 54, 56) preferably substantially normal to the axes of the shafts, are positioned coaxially with an insert (34, 48) positioned between and abutted to the end surfaces. The insert is tapered or wedge-shaped at either end to define transverse contact surfaces (18) which abut the end surfaces of the shafts. The angle (.beta.) of the taper on the insert permits insertion of a consumable arc welding electrode (20) into the convergent space defined between the end surfaces of the shafts and the tapered surfaces of the insert and is large enough to allow the arc welding electrode to be positioned at locations not only sufficiently spaced from both the tapered surfaces and the end surfaces but also sufficiently close to the area of abutment between the contact and end surfaces, to ensure proper welding penetration into the base metals.

Abstract: An improved inflatable seal apparatus (10) is disclosed which includes an annular or closed loop seal element (30, 64) captured during use within an annular supporting channel (20, 54) having a somewhat T-shaped cross-section which is narrowest at its inner, or outer diameter, depending on whether the seal element displaces radially into contact with a body at its outer surface (44) or, inner surface (78), respectively. The seal element is "double-acting" and, when uninflated, is substantially completely positioned within the channel. Upon inflation of the seal element, its inner and outer walls (34, 36 and 68, 70) deflect to essentially the same extent and in the same direction while its radially extending side walls (38, 72) move radially relative to the channel to comply with the simultaneous unidirectional deflection of the inner and outer walls and thus produce a unique "double-acting" displacement.

Abstract: A closure device useable as a test plug to block an extremity of a length of pipe for the pressure testing and repair thereof, including a cylindrical body component formed of two cylindrical half sections operationally readily detachably secured together. The assembled body component of such test plug includes a somewhat T-shaped peripheral channel narrowest at the outer periphery of such test plug body component operationally carrying a circular, inflatable, double acting seal element substantially completely positioned therein when uninflated. On inflation, inner and outer walls of such seal element deform to the same extent, while side walls thereof partially move out of such channel to permit such inner and outer wall deformation; each of such seal element side walls carrying a flange to limit the movement thereof out of such channel.