Sailboat wrote:
I have an old sailboat. The head doesn't have a holding tank. It
discharges overboard. I wonder, can I get a holding tank but not drill
through the deck for a pump out?

It depends on where you are. If you're in coastal water that provide
immediate access to open sea at least 3 miles from the nearest point on
the whole US coastline, you can get away with only an overboard
discharge for the tank. But if you're on inland waters or a large bay
that would make it impractical to get far enough offshore to dump a tank
legally, you'll have to have a pumpout fitting.

The alternative would be some kind of setup that would allow the pumpout
to be connected directly to the tank or into it through a cleanout
port...but pumpout hoses dribble. I wouldn't think you want to bring one
into the boat.

Several others have suggested replacing your toilet with a portapotty.
If you won't use it much, that may be the best way to go. However, if
you have to carry it off the boat to empty it, you don't want a tank
bigger than 2-3 gallons...'cuz waste and water weigh 8.333 lbs/gal,
which would make a 5-6 gallon tank weigh about 50 lbs...a LOT to carry
off the boat and haul up a dock.

Otoh, I don't know what the big deal is about putting in a deck pumpout
fitting. That's what 99% of all older boat owners have had to do.

Tell me about holding tanks with old heads.

For starters, heads do have a finite lifespan....they wear out,
break...mfrs discontinue offering ANY parts for 'em. So depending upon
the make/model/age of yours, you're prob'ly better off replacing it and
starting ov4er with complete new system--toilet, tank, plumbing etc.

As for connecting a tank to an old toilet, that's no different from
connecting a tank to new toilet.
--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/books...ku=90&cat=1304