Problem with B&G Boatspeed

[Streetcar]

Hi all, when underway the boatspeed readout on my B&G Hercules 690 system cycles between about 0.2 kts and 8 kts - up and then down over about 3 mins.

A pair of B&G Sonic Speed transducers are fitted to the hull and leading edge of the keel (they're epoxied in).

It seemed to work fine before I hauled out just recently but the problem started after re-launching.

I've checked the wiring between the transducers and the junction box in the control unit and all seems fine. The only thing I noticed is a little seawater seeping in by the fwd transducer.

If anyone has any similar experience or ideas I'd appreciate it.

Rory

[LeaseOnLife]

I believe, there is a gravity switch, switching between the transducers, depending on heel. You can reconfigure the system to only use one transducer, isolating a possible bad transducer / bad wiring to one transducer.

[Streetcar]

Thanks but I think that's for twin transducers that work in parallel. On this system a sonic signal is sent from one transducer (keel mounted) forward to a receiver transducer (hull mounted further forward). I believe that boatspeed is computed from the increased time for the signal to travel forward through moving water as the boat accelerates from standstill.

[LeaseOnLife]

You certainly are correct, disregard my post....