Horace Brownbag wrote:
The aft sink also has a through hull directly under it, but the
plumbing from holding tank and the fore and aft heads is connected to
it.

The foreward head discharge hose runs that far aft? How long IS that
hose? Optimally, head discharge hose should not exceed 6'...'cuz that's
as far as bowl contents will move in the amount of time 99.999% spends
pumping the toilet. Significantly longer leaves waste sitting in the
hose to permeate it.

The 1/2" intake for the heads is approx 4 feet further away and I
think a bit too small to use as a drain.

Head intake and sink drain SHOULD both be 3/4". If yours is only 1/2",
it's too small for either. 4' isn't too far unless the route leaves a
sag in the hose.

I think I might try Peggy's idea of using a sump. ...the shower sump
is on the other side of the bulkhead.

It might be the best I can do...not having a first choice.

It might be time to redesign the whole system!

--
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://69.20.93.241/store/customer/p...40&cat=&page=1