Air vents for the water tanks are just for venting air (to allow air to
enter when water is being pumped out and to allow air to escape when
filling the tank) not for water escape. If you are using them for water
escape, be very careful. WHen filling the tanks you better NOT have too
much pressure. Even .5 psi can put a lot of pressure on the tops of
tanks - 2'x 5'lid = 24"x 60" = 1440 sq in x .5= 720 pound of pressure,
enough to cause the lid to buckle and separate.

When filling, we always remove the input vent on the top of our tanks
and 'watch' the water filling. Even the exhaust vent in the tanks can
cause pressure.


Hanz

Glenn Ashmore wrote:


Doug Dotson wrote:

To be really safe, put them in the cockit. That way they will drain
out the scuppers and not be so prone to taking in sal****er. Another
option is to put them up the mast a bit. I know someone that did this.
Overflow will go out the fill rather than out the vent. Problem solved
forever.


I set my water tank vents on the outside of the cockpit coaming just
down hill from the deck fill. When the tank is full water flows across
the side deck and out the scupper. You do have to be careful to locate
the vents so that the overflow will not flow back into the deck fill.

Chartered a boat once that had the vent lines run up inside the
stantions with a vent hole just under the top lifeline. Worked great
but if you were holding the hose when the tank overflowed it would spray
you in the face. :-)