[C320-list] Raymarine speed sensor

[Ed Edwards]

I had a similar problem with my ST50 Speed Plus.  The transducer apparently
can leak and short out the ability to transmit info.  The first step in
determining that problem is to remove the transducer and let it dry out.
After 24 hours out of the water mine began working again.

Initially I had a friend use a vacuum cleaner blower to rotate the paddle
wheel while I watched the instrument.  There was no reading.  The next day
the blower caused the transducer the register with  the knotmeter.

You can remove the transducer from the through hull fitting while the boat
is in the water.  Make sure you have the plug before you start and an extra
set of hands may be convenient.  I got about a cup of water inside the hull
when I did it.

The ST 50 unit isn"t available anymore but you can use a different version
with a sleeve.

Ed,  REBOUND #347

On Mon, Jul 6, 2009 at 6:17 AM, Scott Thompson <surprise at thompson87.com>wrote:

> Just got back from three days of terrific sailing on the Chesapeake. I've
> rarely put together good sailing for three days in a row at this time of
> year.
>
> My speed gauge stopped working on day 1.  It had been acting erratically
> last year -- sometimes reading low, sometimes reading speeds in the teens
> while tied to the pier.  Now it just reads 0.00.  The impeller is not
> fouled.  I removed it -- and found it clean as a whistle as it should be,
> since I do not leave it in place when not sailing.  But spinning it by hand
> does not register anything on the display.
>
> Suggestions on how to diagnose the problem would be appreciated.
>
> --
> Scott Thompson
> Surprise, #653
>