Re: venting the holding tank
I have a V holding tank molded into the bow below the berth. The fill or pump-out line attachs to the top in the aft starboard corner near the inspection port. The vent goes into the tank on the top just forward of the fill line. The vent line runs to the bow and exists overboard near the rail in the center of the O in the CO logo.
Re: venting the holding tank
I bought my Contessa with a full holding tank. I tied up at the pumpout station and nothing (very little) would come out. I opened a valve underneath and sea water came in the tank as the (you know what) came out. The holding tank was never vented. A friend installed a vent with a thru-hull vent high on the topside just forward of CO on the top stripe.
I installed a hand operated pump to replace a 12 volt macerator pump that kept tripping circuit breakers. As long as my left arm works I can empty the tank when far offshore. Pumpouts are no longer a problem.
The cutworms are in the hollyhocks, again!
Re: venting the holding tank
Hey Suzeh! If the tank below the cabin sole has never been used, could it hold fresh water instead of sewage? I like the idea of having a weight down low close to the keel. My holding tank travels empty or near empty most of the time, whereas the fresh water tank is full or close to full most of the time.
Re: venting the holding tank
Agree on the placement - low and centered on the boat. After installing my Thetford, I converted mine into a locker for anchor chain and other heavy/dead weight
Re: venting the holding tank
My below the cabin sole holding tank was quite foul when I bought the boat. The bottom of the keel length tank had an inch or more of concrete it's full length. Ballast? I am having the fellow restoring my co26 cut the laminate under the cabin sole, top of tank, and remove all the concrete, clean and seal with epoxy and paint. I will then have a hatch or two put in the laminate, which was the top of the tank, for access to what is now storage area in the lowest part of the boat. I am replacing this tank and head with a porta-potti. This makes so much more sense to me. I think this boat is just to small for this large area to be used for such a large tank and all the plumbing. This will make a great storage area for anchors, fenders, rodes, chain, parts, water in disposal wine bladders from "box-o-wines", etc. etc. I am planning on putting a flexible water bladder in the water tank under the vee berth. I don't like the idea of potable water sitting in a f/g tank.
Did I read somewhere that you must have a holding tank in the Great Lakes? A Porta-potti won't do?