"William R. Watt" wrote in message ...
Ron Thornton ) writes:

I
thinking of using a plastic toilet tank float with a straight stainless
steel rod of maybe 2-3 feet.

a ping-pong ball inside a lenght of plastic pipe mounted vertically?
or a sealed length of plastic pipe set inside the vertical pipe?
either should foat up and trip a switch.

The problem with either of these is that there are 2 components
moving relative to each other and in fairly close proximity to each
other which increases the possibility of something jamming. The
beauty of Ron's idea of just hanging a big plastic ball (i.e. toilet tank
float) from the top of the bilge is that it is very hard to imagine (at
least for me) how this mechanism could ever become jammed.

the oringinal problem posted in the thread was the need for a
damper to keep the pump from getting turned
on and off frequently, I think. you cold weight a sealed pipe float so it
only rises when the water reaches a certaian level and then pumps the
bilge dry before shutting off.

Personally, if I were going the route of using a toilet tank float
so as to lift all the electrics well clear of the water then I would
prefer to introduce the necessary damping into the system
electronically and site the electronics in the wheelhouse (assuming
an inside helmstation) where it is as protected as is possible.

- Julian.