Best Location of Macerator ?

[Sabbatical II]

The location of my holding tank on my new boat under construction is under the vee berth. The builder has told me that the macerator also usually goes under the vee berth. The head is actually back beside the companionway. I am concerned that too much gluggy toilet paper will get stuck in the pipe before it gets to the macerator. If it was macerated at the head, would it be more likely to make it all the way to the holding tank? I have been on an older boat that had the macerator at the head and discharged directly overboard without having to travel all the way forward. Is it possible, or even preferable to have the macerator at the head when using a forward holding tank?

[Bash]

Originally Posted by Eleebana

Is it possible, or even preferable to have the macerator at the head when using a forward holding tank?

Absolutely! On my boat we have macerating toilets, where the first macerator is built right into the porcelain.

A second macerator is located between the holding tank and the thru-hull, of course.

[osirissail]

Okay you are talking about two different things. The MSD has a pump system to moves the waste from the toilet to the holding tank. That can be a manual hand pump that does not break up waste material very much, if any. An electric "macerating" MSD has a motor with a blade system for chopping up the waste and then a pump mechanism to sent it to the tank or overboard. These systems have a rather small outflow hose from the MSD compared to the 1.5 inch outflow hose on a manual toilet.
- - On the outflow/drain fitting on the holding tank you can install a separate macerator pump to empty the holding tank and push the "chopped up" waste material up through a vented loop and overboard through a thru-hull. This pump is normally located very close to the actual holding tank.
- - Locating the holding tank underneath a sleeping bunk is not a preferred location as the tanks normally all leak odors. And if the tanks don't leak odors the hoses do leak odor. There should be someplace else in the boat where the tank can be located.

[Sabbatical II]

Thanks Bash and Osirissail. The pipe from the head to the holding tank is about 1.5" dia PVC. It slopes down to the holding tank and is bonded into the tank so there are no hoses and fittings to leak or smell. The tank is an integral fiberglass tank built into the structural floors under the vee berth and is to be vented through the transom. As the tank has already been built, at this stage relocation elswhere is not an option. I have not heard of other owners of the boats complaining of leaking smells, but I will certainly ask a few more questions of the builder.

[sabray]

Best place for a macerator pump. Can I vote for the rump of a certain politician associated with tea and partying? Really now I like the idea of the tank bottom being above the water line and letting it gravity discharge when needed. Mine does quite well with a sea land pump I think the tank bottom is above the waterline or near. Never had a problem with these pumps very simple but not rated as macerators. The maverators I have seen are better off in someonelse bilge even if its not your favorite politician. Drill Baby and macerator just seem to fit so well.

[osirissail]

Fiberglass holding tank? Unless the inside of the tank is epoxy coated you will over the years start to smell the contents. Holding tanks are normally made of polypropylene which is a translucent type of plastics that has a slippy, waxy feel to it. The very close linking of the molecules do not allow any gases, etc. to migrate through the walls.
- - Using hard "pvc" pipe to plumb from the MSD to the tank - and into the tank - without any "flexible" joints is again asking for leaks and odor migration. PVC pipe is not as smooth inside as you might think. Over time debris will "glue" itself to the inside of the pipe and eventually clog off the pipe just like normal vinyl hose does (scale build-up) over time and use - especially if you are using a sea water to flush the MSD.
- - Boats flex and bend as they travel up and over waves and take a pounding in every conceivable directions. Wiring standards and plumbing standards are very, very different from land housing standards. Everything in a boat needs to be able to flex in all directions and not break or separate/crack which is why vinyl hose, etc. is used in the plumbing systems.
- - If you are only going to have the boat for a few years, no problem, but if it is a major investment for long time use, then I can foresee serious problems ahead. Look into the heads and bilges of boats in the boat shows and you will see what is being used and how it is connected. These manufacturers do not want to have serious problems coming back to bite them years down the road so use materials and techniques that are proven to work.
- - I installed a "grey" water drain system in my boat in anticipation of future governmental regulations about such things as sinks and showers. There are threads about Turkey and grey water regulations. I did use pvc pipe for the 30 foot run from the forward head to the engine room where the grey water tank is located. The pvc pipe is sloped and held with tiedowns every 2 feet. Flexible hoses connect the pvc pipe to the tank and sinks/showers. And - - 10 years later, the pvc pipe is clogged with debris and cannot be removed or cleaned short of ripping out the whole sidewalls of the boat. A great idea that did not work in reality.
- - Bottom line - If you plan on only having the boat for a few years at most, then no foul, no harm. But if it is a very long term investment I would seriously suggest ripping out that tank and pvc piping and use "normal" accepted/proven standards for MSD plumbing and MSD rated hoses which are different from the normal vinyl hoses used for other systems in a boat. I believe SeaLand sells the special hose.

[Sabbatical II]

The holding tank is definately epoxy coated. I will look into the pipe issue. Many thanks.

Greg