We own a 1988 Hunter 35 (aka legend 35.5) - the previous owner renovated and modified the head holding tank. The original metal 14 gallon holding tank was replaced with a 25 gallon plastic holding tank. I believe that the location of the new tank is different than when the boat was built. I am looking for information where the original holding tank was located. The current placement is in the starboard side locker. The inlet to the tank is approximately 30 inches above the head outlet. Any help or pictures will be greatly appreciated.
88 Hunter 35 Head holding tank placement
- Thread starter Irish Cream
- Start date
Why? Boat builders are the worst sanitation system designers on the planet, so the odds are very good that the tank is actually in a much better location than the original tank...it certainly holds a lot more flushes! If the only real problem is a long uphill--and apparently pretty steep--run from the toilet to the tank, that's just a plumbing problem that's actually pretty easy to solve. Because the specifics of exactly how to re-plumb it on YOUR boat require the answers to some questions about the existing system, we're gonna need some one-on-one conversation to figure out how best to do it....so how 'bout sending me a PM?
Received a reply from an owner of a 1987 35. He stated that his holding tank placement was the same as ours on our 1988 35. Guess our next step is to study the situation when we up-tarp this spring after winter lay-up. We have some ideas, but until we can get back aboard, it's hard to devise a correction plan. As an FYI, we also contacted Marlow-Hunter and they declined assistance on any vessel built before they took ownership after Hunter went bankrupt in 2012.
Our '88 has the holding tank along the side of the hull in the lazarett. It rests on the pan grid and tied down with straps. The specs say it's 22 gallons.
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That diagram matches where my tank is. Mine was replaced with SS a some point in the past. I did some calculations a while back and figured my tank was about 15 Gallons. Too small for our use. The "shelf" (of the liner/grid structure) extends the whole length of the lazarette, so putting in a longer tank would not be hard.
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That's easy to fix.
Unless the tank is full or close to full, the backflow isn't coming from the tank, it's waste in the head discharge line that isn't making to the tank. The fix: install a loop--not a vented loop, just a loop--in the toilet discharge line immediately after the toilet that's slightly higher than the top of the tank. Then all you have to do is flush long enough to push waste over the top of the loop. To prevent what's left in the line between the toilet and the top of loop from running back to the toilet, learn to use the dry mode to do more than just push the last of the water out of the bowl. Most people don't realize that any toilet that's working anywhere near factory specscan move bowl contents up to 4' IN THE DRY MODE. This does require a joker valve that isn't worn out (see the article "joker valve 101" in the archives of the plumbing and sanitation forum and my book to learn the joker valve's REAL function, which is much more important than just blocking backflow)...so after you push the "deposit" over the top of the loop in the dry mode, switch to wet to bring in some flush water to rinse behind it...then switch back to the dry mode to push the rinse water over the top of the loop. This not only will cure your backflow problem but has the added advantage of reducing the amount of flush water enough to increase the number of flushes your tank can hold by at least 50%.
The following applies to ALL toilet installations, no matter what route the plumbing takes: If the "deposit" will be solids, add about a quart of water to the bowl ahead of use. This will keep the bowl clean and require much less flush water to move the flush to the tank. If your toilet isn't designed to bring water into the bowl and hold it there, use water from the sink...two 16 oz Solo cupfuls.
A little more effort, but a LOT cheaper than replacing the tank and all the plumbing.
Unless the tank is full or close to full, the backflow isn't coming from the tank, it's waste in the head discharge line that isn't making to the tank. The fix: install a loop--not a vented loop, just a loop--in the toilet discharge line immediately after the toilet that's slightly higher than the top of the tank. Then all you have to do is flush long enough to push waste over the top of the loop. To prevent what's left in the line between the toilet and the top of loop from running back to the toilet, learn to use the dry mode to do more than just push the last of the water out of the bowl. Most people don't realize that any toilet that's working anywhere near factory specscan move bowl contents up to 4' IN THE DRY MODE. This does require a joker valve that isn't worn out (see the article "joker valve 101" in the archives of the plumbing and sanitation forum and my book to learn the joker valve's REAL function, which is much more important than just blocking backflow)...so after you push the "deposit" over the top of the loop in the dry mode, switch to wet to bring in some flush water to rinse behind it...then switch back to the dry mode to push the rinse water over the top of the loop. This not only will cure your backflow problem but has the added advantage of reducing the amount of flush water enough to increase the number of flushes your tank can hold by at least 50%.
The following applies to ALL toilet installations, no matter what route the plumbing takes: If the "deposit" will be solids, add about a quart of water to the bowl ahead of use. This will keep the bowl clean and require much less flush water to move the flush to the tank. If your toilet isn't designed to bring water into the bowl and hold it there, use water from the sink...two 16 oz Solo cupfuls.
A little more effort, but a LOT cheaper than replacing the tank and all the plumbing.
There is a lot of thought, and very custom fitting, that would be required with a tank project. Adding on to what Peggy mentioned, there are also the tie down straps and the anchors for them. The problem that doesn't show up in the drawing is all the curved surfaces, the structural members of the grid, other items like the water lift muffler (and exhaust hoses), and the fuel tank. The ledge width isn't very large so that provides a constraint to the width of the tank. As mentioned, the ledge runs aft so a longer (and skinny) tank is an option.
Thank you all for the reply's. We have a lot of information to review and to devise a plan to resolve the back flow problem with our head holding tank. We will address the problem when we take the tarps off and prepare the boat for our seasons sailing.
You're welcome to contact me directly if you need more specific help than is practical in a forum. I'm always glad to help!