Electromagnetic boat speedometer having removable electrodes

摘要

An electromagnetic speedometer for a boat having hull containing an opening includes an electromagnetic coil supported by the hull for establishing an electromagnetic field in the water adjacent the hull opening. A plurality of electrodes are supported by an arrangement that both closes the hull opening and supports the electrodes in engagement with the water adjacent the hull opening. The electrodes are connected by conductors with a velocity measuring circuit arranged above the hull interior surface. Preferably, the electrode support arrangement includes guide tubes supporting the electrodes for removal relative to the boat hull, thereby to permit cleaning of the electrodes. The guide tubes are closed by valves when the electrodes are removed from the assembly. In one embodiment, the electromagnetic coil is of the end-fired type, and in another embodiment, the electromagnetic coil is annular and is arranged above and below the hull.

主权项

1. An electromagnetic speedometer for a boat, comprising:
(a) a horizontal boat hull (4) having a lower exterior surface exposed to the water, and an upper interior surface, said horizontal boat hull containing at least one through opening; (b) an annular electromagnetic coil (304; 404) mounted on said horizontal boat hull for establishing an electromagnetic field in the water adjacent said horizontal boat hull lower exterior surface; (c) a plurality of electrodes (314; 414) having first ends terminating in electrode tips, said electrodes having second ends; (d) an electrode support arrangement removably supporting said electrodes within said at least one horizontal boat hull through opening to effect engagement of said electrode tips with the water adjacent said electromagnetic field, thereby to permit removal of said electrodes and cleaning of said electrode tips when the boat is in the water; (e) a velocity measuring circuit arranged above said horizontal boat hull upper interior surface, said velocity measuring circuit including a plurality of conductors respectively connected with said electrode second ends; and (f) closure means (312; 412) for closing said at least one horizontal boat hull through opening upon removal of said electrodes therefrom; (g) said electrode support arrangement comprising a synthetic plastic shroud member (308; 408) having a generally inverted-mushroom-shaped configuration including a horizontal body portion secured to said horizontal boat hull lower exterior surface, and a stem portion that extends upwardly through said horizontal boat hull through opening, said shroud member containing a plurality of guide passages (307; 407) that extend downwardly through said shroud stem portion and radially outwardly in said shroud body portion toward electrode tip openings (306; 406) contained in the bottom surface of said shroud member; (h) said electrodes (314; 414) being flexible and removably extending in said guide passages downwardly through said shroud stem portion, and radially outwardly in said shroud body portion toward said electrode tip openings.