Dave wrote:
Was at the boat this weekend, and found that the seacock on my head's
through-hull discharge was frozen in the closed position. The PO had
disconnected the Y-valve to the through-hull, and just routed all discharge
to the holding tank. I'm replacing hose, and am thinking of doing the same
if it can't free up the seacock. If I do this is there any need for a vented
loop? Another owner has one installed between the head discharge and the
holding tank, and says it's to prevent siphoning back from the holding tank.
Since the inlet to the holding tank is near the top, is this really a
problem -- do I need a vented loop?

On a powerboat, no....'cuz powerboats don't heel. But on a sailboat, if
the inlet fitting on the tank is toward the hull instead of toward the
centerline of the boat, a loop--though not necessarily a vented loop--is
a good idea to prevent tank contents from running back toward the toilet
when you're heeled.

It's not necessary if the inlet and vent fittings are toward the
centerline because waste in the tank runs to the side away from the
fitting on one tack, the hoses run uphill on the other tack. Worth
remembering when you spec out an installation.

--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://www.seaworthy.com/html/get_ri...oat_odors.html