Lavezzi 40: Retrofitting Holding Tanks

[Roy M]

I built a custom tank out of epoxy-coated plywood. It has twin, 1 1/2 inch vents mounted on each side of the bow to ensure excellent ventilation for the aerobic digestion bacteria that keep the stink down. Because the tank is above waterline, as the other pictured tank, there is no need for macerator pumps for discharge when in open seas, and the tank can be pumped out at the deck when in port. The toilet is a Lavac with minimal moving parts (if you don't count the toilet seat). The platform above the toilet lifts up for access, but normally is in the down position to allow a very large crew member to stand on it to pull a spinnaker down the hatch, if needed, or provide a comfy seat to take a shower.

[EllisElectric]

Why not go with dry composting heads?

[PaulinOz]

The top suction outlet lines up with the round molding in the center, so my guess would be to hold the bottom end of the suction evacuation pipe inside the tank. This needs to be a pipe that is held near the bottom of the tank when using a pump out station. Hope this helps.

[olaf hart]

Originally Posted by PaulinOz

Tank is 45 lt
800mm High
400mm wide
Tapered
at the top 250mm front to back.
at the bottom from 100mm front to back.

Picture is a Panorama scanning up, the tank has straight sides not wavy as pictured. This is all covered by a Fiberglass cover panel.

Any idea where the tank comes from?
The cutaway moulding also holds the pump out pipe directly over the outlet, so you can clear a blockage down the pump out fitting.

[PaulinOz]

Original Equipment in a Lavezzi 40 from Fountain Pajot.

[Marcsailcat]

I have the stock holding tank from FP but I replaced the head with a Raritan Marine Elegance with fresh water flush. When I replaced the head I also installed all new hoses. I noticed the hose goes from bottom of toilet up and into the top of the holding tank which (like yours) is mounted near the top of the bow. Distance from bottom of toilet to top of tank is nearly 5-6 feet. Raritan claims toilet has enough power to pump effluent to top but I wonder if solids (that have been macerated by toilet) will accumulate in hose at bottom. Am I worrying too much or is this ok?

[PaulinOz]

I have a similar height from pump to tank entry on both my Lagoons (total) of 5 heads) and they work OK. You will have issues / blockages over time but that is just the nature of the beast. Not caused by pump height more to do with what goes in to pump and if enough water is flushed to push the muck into the tank and clear the pipe.

[Grateful]

Paulin,

Thanks for that. One last question:

Can you describe the routing for the deck fittings? Doing a quick survey with a tape measure, It would appear that the stbd side must go through the locker behind the settee adjacent to the nav station. I haven't surveyed port yet.

[PaulinOz]

Sorry Grateful I will have to leave that for an Lavezzi 40 owner.
I have a couple of Lagoons.
I was anchored next to a Lavezzi and getting the Info for a friend who has just purchased a Lavezzi 40 without holding tanks in the Caribbean. He is currently in Oz and returning in November for the boat.

[Grateful]

Bump here.

Surly someone with factory installed holding tanks in an FP Lavezzi 40 can give me some guidance as to the routing / location of the pump-out plumbing. I'm on the verge of installing dummy deck fittings to satisfy any casual inspection that might come up whilst in the US and using only gravity discharge into the water.

I'd really rather do it correctly if I can...

[Roy M]

Just install a tee fitting into the discharge hose and route a hose to a deck fitting. The vent is already installed, and nothing suffers if you never use the deck pumpout.

[Grateful]

Roy,

Thank you for your quick response. I'm afraid that I was a little vague in my question. I understand how the valving and venting work. What baffles me is the actual routing of the pump out pipe.

In Paul's photo of the tank in the starboard head posted earlier in this thread, you can see the pump out going directly out of the tank and through the overhead. Problem is, directly above that part of the head, I believe that is dead space behind a settee next to the nav station.

Did FP fit the pump out fittings in the side of the house? Does the pipe make two tight 90 degree bends and come out through the deck? Did they route them forward into the anchor locker? The port side routing has similar challenges. I'm at a loss as none of these solutions seem very good.

I've scoured the Internet for photos of Lavezzi 40's and have yet to see a pump out fitting on deck in any of them.

[Roy M]

Fortunately, hydraulics work predictably. Suck at one end, extract at the other. When you stop sucking, the remainder in the pipe falls back to the lowest end. Route the extraction tube as short and direct as possible. Then, when done sucking, don't worry about it as it will just go back to the tank or the lowest remaining section of hose. Later, you can open the gravity drain and be done with it.