Join Date: Jan 2006
Location: living aboard since 1972
Thanked 12 Times in 12 Posts
Rep Power: 11
Dreamalbin, I'll bypass the photos or diagram, but I think I can write your way through the most efficient functional plan. Influent water for the head would enter at a through-hull with a seacock or ball valve near the head to provide water for flushing. The effluent hose from the head, typically 1 1/2" would lead to the top of the holding tank. The top of this holding tank would also require a fitting to attach a vent hose. The preferred run for the vent is to loop it well above the waterline but to have it exit low and aft so odors won't waft across the cockpit or deck hatches when air is expelled from the tank. The 1 1/2" hose removing material from the bottom of the tank is best lead to a "T" fitting close to the tank (no Y-valve is required here or in this entire simple system). One effluent from the "T" leads to a deck fitting for pump out and the other effluent from the "T" leads to a macerator pump equal to the base of the holding tank. A higher placed macerator may have priming problems and too low makes repair a big risk of mess. The best choice is to have enough hose to detach the macerator and raise it higher than the tank contents for repair. The effluent from this macerator would then lead to a through-hull. No Y-valve is needed for this system because, during pump-out, material is not pulled backwards through the macerator and all suction is applied to the tank and when the deck pump out is closed all suction is applied to the holding tank by the macerator. Regulations in US waters will require that the effulent seacock or ball-valve from the macerator is locked in a closed position or that the access to this closed valve is locked. An added avantage of this system is, if your macerator ever lacks function due to an air lock and lack of priming that can occur after rolling in rough seas; then, a simple cure is to pour a little water into the deck pump-out fitting. 'take care and joy, Aythya crew
Last edited by CaptainForce; 03-31-2009 at 02:32 PM.