Well, this thread has me thinking, as neither of our heads has vented loops
in the intake line, and the aft head is distinctly under the waterline (fwd
isn't except on sharp port tack).

So, if I understand vented loops properly, suction gets air, rather than
water, thus preventing siphoning. So, how do you suck in the supply water
if the supply line is vented???

L8R

Skip, scratching his head, pardon the expression (solidly asking pardon for
the other - inferred solid - expression)

--
Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/384p2 The vessel as Tehamana, as we bought her

"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore.
Dream. Discover." - Mark Twain