Re-plumbing the head

Posts about the Galley and Head systems, including plumbing, water, and propane
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Dan

Re-plumbing the head

Post by Dan »

One recommendation I have for Telstar owners who are looking to cruise longer term on their boats is modifying the head to allow you to pump out the holding tank while at sea.

To do this, I modified the way the head is plumbed. I re-routed the head’s output to pump directly into the holding tank. I then added a diverter valve to the holding tank’s deck pumpout hose. The diverter valve allows you to select either the deck pumpout fitting or a Whale Gusher Mk V diaphragm pump that is connected to the ball valve and through-hull that was originally connected to the head’s output hose.

This setup increases the flexibility of the Telstar’s head system, and allows you to pump out the holding tank, even if pumpout facilities are not available. While you can no longer pump the head directly overboard, it really doesn’t matter, since you can now pump the holding tank overboard where ever you might have discharged the head directly overboard.

I also cut an opening in the holding tank and added a Beckson 6" inspection port with a transparent deck plate. This allows me to check the level of the holding tank without having to open it. It also allows me to clean out the holding tank as necessary.
trashpad

Re-plumbing the head

Post by trashpad »

With the location of the small tank and the overboard discharge, I would think a gravity discharge system would work. I would have to check the water line as it might be a few inches above the bottom of the tank but a simpler option that drained 80% might be a good option.
Dan

Re-plumbing the head

Post by Dan »

Kurt—

I'm a bit confused, as I don't believe the holding tank location has changed and on my boat it is forward of the head, located in the very bottom of the forepeak area. This means that most of the tank is below the waterline. That means a pump is required to drain the tank. If your tank is located in a different location, please tell me where it is and what kind of tank it is. :)
trashpad

Re-plumbing the head

Post by trashpad »

The bottom of the tank is below the waterline but only a few inches. I was thinking that giving up the ablity to fully drain the tank for a system with no moving parts might be worth it.
Dan

Re-plumbing the head

Post by Dan »

I don’t believe that is even possible, unless your boat has a different holding tank design than mine does. The lowermost twelve inches or so should be below the waterline on the stock Telstar holding tank, which is located in the forepeak, underneath a plywood panel. Even if you ran the hose directly from the fitting to the seacock, you’d only drain the top few inches of the holding tank at most. That setup would also leave raw waste sitting in the hose its entire length most of the time, making the chance of the hose becoming permeated and causing odors much greater. Never mind that the 90˚ fitting at the base of the holding tank for the pumpout hose would make routing it directly to the seacock very difficult.

In fact, I had spoken to Tony and Will about the holding tank and how to be able to empty it without pumpout facilities prior to buying my boat... and Tony stated that the Telstar’s tank needed a pump to evacuate it, unlike the holding tank in the Gemini, which is considerably higher than the water line and will gravity drain.
Ron
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Re-plumbing the head

Post by Ron »

Dan & Kurt -

You're both half right or half wrong. My boat's up on the lift now and I can easily see the shape of the main hull. The tank is towards the bottom of the forepeak area, but that's probably close to 6 inches higher than the rest of the hull further back. Some stuff may come out via gravity, but probably not enough to warrant doing all this work. A pump is the only way to do it.

Maybe think about pumping seawater into the top of the tank? That would tend to flush stuff out of the bottom. You'd have to get a better idea exactly where the tank is as compared to the water line. It looks like it's around half way. But also note that EVERY hole in the side of a boat increases it's chance of sinking.
Ron Marcuse
Telstar 28 #359 "Tri-Power"
Dan

Re-plumbing the head

Post by Dan »

Ron—

I don’t see any point in pumping seawater into the tank, when a diaphragm pump, like a Whale Mk V will do the job of getting rid of almost all of the waste. An anti-siphon loop probably isn’t even required, since the Whale Mk V acts as a check valve.

Also, I haven’t added any holes in the hull to do this. The holding tank pumpout hose leads to a y-valve, which either connect to the deck pumpout fitting or to the hose going to the Whale Mk V, then to the seacock and overboard, through the existing through-hull that was factory installed. The diverter valve I’m using is not the one supplied by the factory, since that is more of a T-shape, than a Y-shape and more likely to clog. I’ve used this setup for the better part of two seasons, and it seems to be working as expected. :)
Ron wrote:Dan & Kurt -

You're both half right or half wrong. My boat's up on the lift now and I can easily see the shape of the main hull. The tank is towards the bottom of the forepeak area, but that's probably close to 6 inches higher than the rest of the hull further back. Some stuff may come out via gravity, but probably not enough to warrant doing all this work. A pump is the only way to do it.

Maybe think about pumping seawater into the top of the tank? That would tend to flush stuff out of the bottom. You'd have to get a better idea exactly where the tank is as compared to the water line. It looks like it's around half way. But also note that EVERY hole in the side of a boat increases it's chance of sinking.
Ron
Posts: 1136
Joined: Mon Nov 24, 2008 6:15 pm
Location: SW Florida
Contact:

Re-plumbing the head

Post by Ron »

Dan -

Your pump is the best solution, but I was trying to think of a way to do it like Kurt wanted to (without a pump at the bottom of the tank). In theory, a short wide hose running directly to a through-hull and then flaring the hull just before it would create a negative pressure and tend to evacuate the tank when you're moving. But you'd never be able to install or reach the required seacock. Theres not much room to work down there. Getting water into the tank would also tend to coax some of the contents out.
Ron Marcuse
Telstar 28 #359 "Tri-Power"
Dan

Re-plumbing the head

Post by Dan »

Considering how viscous the fluid in a holding tank can be after it settles a bit... I’d imagine it takes a bit of height differential to get it flowing well, if at all, and I don’t really think a SIX-INCH head is going to do the job. That doesn’t even address the issues of trying to get the hose from the tank to the seacock, without rising above that point—which, given the fitting on the tank and the design of the seacock, I don’t even believe is possible. :)
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