On Sat, 15 Oct 2005 13:47:27 -0400, dh@. wrote:

How do the boat lifts that use air work? If they have a check
valve to let water out the bottom when they force air in, how
do they let the water back in to sink it? I thought maybe a
solenoid valve, but don't see any wires running to the float
tanks...only what appears to be an air hose. Is HydroHoist
the only lift that uses air? I read that they have a patent,
but they can't have a patent on the concept of using air
to lift a boat can they?


I am speaking out of turn - because I don't know how the model works
that you are talking about.
But if *I* had to do a lift, an air line connected to the float and
selectable for a pressure source, or an atmospheric vent would work
perfectly well would it not?

Brian Whatcott altus OK