| 摘要 |
The invention relates to:
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;
(b) an annular coil (504) mounted on said boat hull upper interior surface for establishing an electromagnetic field in the water adjacent said hull lower surface;
(c) a plurality of electrodes (514) having tips at one end;
(d) a plurality of generally vertical guide tubes (507) containing guide passages for removably supporting said electrodes within corresponding through openings (4a) contained in said hull concentrically within and separate from said annular coil, thereby to effect engagement of the electrode tips with the water adjacent said electromagnetic field, and to permit removal of the electrodes and cleaning of the electrode tips when the boat is in the water;
(e) a velocity measuring circuit arranged above said hull interior surface, said velocity measuring circuit means including a plurality of conductors respectively connected with the other ends of said electrodes; and
(f) closure means (512) for closing said guide passages upon removal of said electrodes therefrom. |
