[Sentoa] Holding Tank lights and switches

[Simon Bergen-Henengouwen]

I recently attended the Port Townsend Nordic Tug Rendezvous and heard 
Bob the plumber say that we should regularly clean the switches or 
probes in the holding tank.  Apparently the probes are reed switches 
which need cleaning occasionally. I can now attest to that now as I 
have a Green and a Red light on at the same time.  I should have 
asked him in detail how this was done because I now need to do it.

Has anyone done this?  When I get on my hands and knees (which is a 
feat in itself as I am 6'5"), I see a black cover about 6" in 
diameter screwed to the top of the tank with 5 Robertson screws 
(incidentally these are a Canadian invention and are great to work 
with) in a very difficult to reach place just below the front of the 
engine. I believe this black cover is probably sealed to the tank as 
well. On top of the black cover is a white cap about 5" in diameter 
with knobs that stick out suggesting that it turns. Onto this white 
cap there are three knobs capped with black tops what I believe are 
the level sensors for the tank each with a white double wire coming from it.

I would really welcome the easiest way of extracting the sensors?  I 
think my long arms might come in handy after all! Does one simply 
unscrew the white cap?  Do the wires need to be disconnected first 
and if so how are they held on? And what is the best way to clean the 
switches? As space is at a premium and distances are long these tips 
would be of great help.

Simon

Simon and Sonia Bergen-Henengouwen
SINOMA, 32-217
White Rock, BC (moored in Blaine, WA)