Abstract: Boat hulls or assemblies have sequences of groups of downward-facing sections such as planing sections. A sequence includes a lowermost group and supplemental groups above it. Each group could, for example, be a pair, and the pairs could be port-starboard symmetrical. The lower surface is shaped so that the boat hull, in a series of speed ranges, planes on successively lower groups, planing on the lowermost group in the highest range. The trim angle can be between 3.0° and 6.0° in a speed range. The boat hull can be structured so that, when planing on one of the groups, the next higher group dries out. For example, each pair of sections can have an outward angle not smaller than the next inward pair's. The lowermost group can have a maximum width approximately equal to an ideal beam width for a set of displacement characteristics and its target maximum speed.

Abstract: A centrifugal fan provided with dampers is driven by a motor having a speed control circuit. Air flow from the centrifugal fan is controlled from a point of maximum air flow to a predetermined crossover speed only by changing the velocity of the fan impeller with subsequent air flow control at air flow rates below said crossover speed being attained only by adjustment of the fan dampers.

Abstract: A centrifugal fan provided with dampers is driven by a motor having a speed control circuit. Air flow from the centrifugal fan is controlled from a point of maximum air flow to a predetermined crossover speed only by changing the velocity of the fan impeller with subsequent air flow control at air flow rates below said crossover speed being attained only by adjustment of the fan dampers.

Abstract: In an electrical power generating installation which includes a plurality of turbine-generator sets, a parking bus is disclosed, which is provided with a potential regulated at a relatively low and constant frequency of the order of 1-2 Hz. Switching and phase and frequency matching means are provided, which enable the same controlled variable frequency starting system used for start-up of the turbine-generator sets, to be used for gradually adjusting the rotational speed of a selected turbine-generator set to a point where phase and frequency may be matched with that of the parking bus, to then permit the generator member of such set to be electrically transferred to the bus. By means of such arrangement, any number of turbine-generator sets may be connected in parallel to the parking bus which thereupon effects a simultaneous, continued low speed rotation of the sets for cooling or other purposes.