Hi,
I am looking at fitting a holding tank and need help with options for set up.

How big does the tank need to be? Two crew on the boat, storage for 48 hours would be enough. I can find space for around 60 litres.

I will include a macerator in the system. The macerator can be part of a new electric toilet that delivers to the tank. The tank will then be gravity drained. The alternative is to locate the macerator after the tank with a pumped discharge. A electric toilet would be nice, but are there likely to be blockage problems with a gravity discharge of the tank. The gravity route will be short and straight, no kinks etc.

The toilet is forward in the boat (near the mast), so venting the tank to the stern is not an option. Does anyone have experience with venting the tank to the anchor locker? Is this arrangement likely to result in smell drifting into the cabin, cockpit etc?

Thanks for any help.

I fitted a 50 litre square tank.......it's gravity drained as I strapped it to a bulk head above the waterline. It last 48 hours with 2 people on board. The vent is strait out the side at just below deck level. I have a TMC electric toilet with built in macerator in two years since production never had a tank blockage.

southace,

Thanks, how is the vent out the side arranged? Is there a cover to keep water out when heeled?

It wouldn't matter, I doubt much water would come in and if it did it would most properly flush it out a bit. I keep it open most of the time accept in prohibited areas! I just used a plastic 1 inch skin fitting for the breather. I think the whole job including the electric TMC cost me about $600.
I had a Jabsco hand plumb loo for many years! I really can't believe these 2005 and above production yachts most seem to have hand pump toilets first thing I will be doing is placing them in the rubbish and fitting electric loos!