How to set up the plumbing

[debiby]

All the plumbing on this old boat has the drains going straight out the side of the boat, even the head. I am sure this is wrong now adays and need to know how to set it up. I am sure I need a holding tank for the head but do I also need a gray water tank as well? Also where do you locate the hookup for the drain hose when you pump the waist out? I hope these aren't to dumb of questions but I haven't been able to find any info on the proper way to set it all up.
Dan

[Al Benton]

Dan,

Yes, a holding tank would be needed for the head but not for gray water (unless there are special restrictions on the water you're on). I've taken the simple alternative. I removed the head and use a porta-potty in its place (much easier to deal with for me). It's self contained, portable and easy to clean.

A preferable location for a holding tank would be under the aft deck so pumping out would be more accessible. It should be as close as possible to the head though in order to keep the plumbing as short as possible.

The plumbing is simple. If you already have a head (manual or electric) it has a raw water line from a thru-hull fitting for providing flush water. The discharge line from the head would be plumbed to the top of the new holding tank in as straight and short a run as possible. The only other necessities are a pumpout line to a flush deck fitting and a holding tank vent line (to somewhere overboard). If you think it will be used for solid waste you would be well advised to invest in a Macerator Pump (grinder) or an electric head (with built-in grinder).

Al

[Wood Commander]

Those are actually pretty good questions. There is a world of difference between current plumbing drainage methods and the old days. Yes, you are going to need a holding tank. It will need to be vented, and all of the hoses are very important. They make good and better (read more expensive) hoses that won't let odor permeate them. The emptying is done via a marina pump out station that sucks the tank out. You usually get to pay for this service, woohoo! Everybody loves paying for something like that! So you can usually flush mount the pump out cap on the deck somewhere. On my boat it is on the Port side deck about even with the helm station. Make sure that you get a proper cap fitting with a chain- captured cap so you don't lose it overboard when the first year college student working at the gas dock for the summer opens the cap to put the suction hose in. And it needs to be marked "pump out" or "holding tank" so the same dock boy doesn't fill your holding tank with gas. The fittings are available at ant good marine store like WEST or Boat U.S. The WEST Marine catalog has how- to sections in many of the different chapters covering equipment found in the chapter. They can be pretty good sources of info.
For grey water you can probably use the old drain set up. I guess it depends on just what you are going to have in your grey water. There may be laws about this but I am not aware of any.
You have to remember that any hose that drains out of a through hull fitting has the potential to let water siphon or get pushed back up the hose and into the boat. This is even true above the waterline if you are in heavy seas or get heeled over for some reason or even by backing down. Notice how the through hull plumbing drain fittings are always hooded over in the front so that the discharge points to the rear and down and is shielded from flow over the opening when moving forward? It is probably safest to always have a trap and/or siphon breaker in any discharge line. But that can be nearly impossible for a sink drain that only has a small amount of water going out and depends on gravity to do it. About the only thing that saves it is that the sink is fairly high in the boat.
That should give you a few ideas to think about. Others will probably have more ideas to share too.