William,

I chose the tank float because of the amount of buoyancy which will
definitely be enough to trip a microswitch directly. The mass of the
float and rod might give the delay effect you want but it would also
leave some water in the bilge, which is not a problem for me cause my
bilge is dry except when it rains (got'a seal those leaks) or I'm
underway with the shaft slightly dripping.

I have trouble getting my 14 ton sailboat on the cartop.

Regards, Ron