When I tried "Lavac" in the search function I was asked if I meant "Lava" which I thought was quite humorous in the context of the inquiry. The search suggests that no one has tried to replace the OE head with a Lavac unit. This is the manual toilet that uses a separately located diaphram pump to create a vacuum and thereby empty the head after use. It is reported to use very little water and therefore greatly extend the life of the holding tank while cruising. A number of users have reported great satisfaction with the Lavac. See: http://www.lavac.com/
Is there anyone out that has secretly been enjoying the pleasures of the Lavac who would care to weigh in on this compelling topic?
I put a Lavac in mine. I put the electric version in. I ended up mounting the pump and switch on a piece of starboard that was mounted to the bulkhead behind (outboard) the toilet. What I liked was the simplicity of operation. The design allows you to leave the head thru-hull open all the time (while on the boat; I always closed every thru-hull when I left). And flushing was as simple as pushing a button. On all my boats I always minimized holding tank usage by "dry flushing" #1 and only wet flushing #2. On the Lavac "dry flushing" is accomplished by flushing with the seat up. Since the bowl was dry most of the time I would add a little water with the shower sprayer before going #2 which improved the evacuation of the bowl. If you want more info shoot me an e-mail and I'll see if I can get some pictures from the new owner.
John,
I got the same thing when I used the search box at the top of this page. However, if you click on the search tab (below and to the left of the search box) you will get a page that does a more comprehensive search. Lavac will bring up about a half dozen posts I made in the past.