Abstract: A marine instrument, such as a clock, barometer, or thermometer, has a face having indicia associated with the face, an instrument movement, and at least one hand having a direct or indirect connection to the movement and positioned to move with respect to the face, or a display connected to an electronic movement. The components are encased within a casing that is water tight to at least 12 inches (e.g. about 30 feet) of water. A vent, such as a porous plastic plug, allows the passage of air in and out of a substantially water-tight volume containing the movement, but precludes water passage up to the rated pressure.

Abstract: An analog pressure indicator assembly, particularly useful as a barometer, accurately indicates pressure or pressure changes using the fewest number of and/or least expensive components possible. The assembly is typically gearless, and includes a pressure sensitive element [e.g. aneroid chamber] having a first portion that moves in a path in response to pressure. A cam has a first curved surface and a second surface, and is mounted for rotation about a first axis, and the curved first surface operatively engages the pressure sensitive element. A force transmitting element, and a shaft mounted for rotation about a second axis spaced from the first axis, and a pointer operatively connected to the shaft, are also provided.

Abstract: A piezoelectric drive, and the rotor and/or pushers thereof, have long life, e.g. at least about 6000 hours of actual operation. The piezoelectric drive also is highly accurate, and is relatively inexpensive to make. The rotor friction surface and/or pushers are made from a material having a low mechanical quality factor, yet with high strength and stability under the conditions encountered in the ultrasonic fields typical of piezoelectric drives. The material is preferably a semi-crystalline thermoplastic polymer (e.g. polyarylamide) with filler (e.g. glass particles or fiberglass), e.g. about 30-60% polymer and about 40-70% filler, and can easily make injection molded components or parts or components. A pair of drives may be connected together to form an instrument, for example rotating a shaft connected to a pointer of analog instrument either clockwise or counterclockwise. Analog instruments, such as thermometers, barometers, speedometers, altimeters, pH meters, anemometers, etc.