New holding tank and plumbing, '82 H37c

[DougMai]

The original aluminum holding tank gave out on my '82 H 37. I want to replace the tank with a larger one. My preferred location is under the shower seat and extending into the starboard locker (I have an AC compressor in the center v-berth locker so all the suggestions about putting it there do no good for me).

I started by cutting around the tank from the forward locker (photo 1). The tank would not come free. It was obvious that it was tabbed in under the seat. After lots of research on the forum, eventually I decided to go forward and cut out the shower seat (photo 2). Oh, and I temporarily removed the partition between the head and shower and the cabinet. Whether this is a good idea or not, time will tell. At least with the seat out I could release the tank from the hidden tabs of fiberglass that were holding it in place. If anyone wants to know original tank dimensions, I have a measured drawing of my original aluminum tank (photo 3).

At this point I am searching for a suitable new tank. Would prefer a manufactured plastic tank but haven't found an acceptable size/shape. Cost of custom plastic and stainless steel is too high. Starting to consider building my own fiberglass/epoxy or having a custom aluminum tank welded. My boatyard neighbors don't see anything wrong with an aluminum tank, I expect a different opinion from the forum.

And since I'm designing a tank, it's time to rearrange the plumbing too. Photos 4 and 5 are existing and alternative plumbing designs, respectively. This will get the hoses out of the port hanging locker and port v-berth locker. I won't try to describe all here. If you have time, take a look at the drawing and let me know what you think.

Thanks for all the info on the forum. I hope to follow and make many more modifications based on Hunter Owners' posts.

 

[Johnb]

Thank you for sharing - I for one am interested in this project.

FWIW I would not go with a metal tank.

 

[DougMai]

Got a quote today for a 40" long aluminum tank for $292.00. I know some will not approve but I ant afford a custom plastic or stainless tank. I will be ordering the larger aluminum tank.
But before ordering, must make a full size mock-up to make sure it fits. And I did that today. Photo 1 shows the mock-up next to the original aluminum tank. Photo 2 is the mock-up in the original location. Photo 3 is the mock-up extending into the starboard v-berth locker. Photo 4 is the shower seat fitted in place over the mock-up. It all seems to fit better that I hoped for.
It may take two weeks to fabricate the tank. I'll spend that time thinking about how to support and secure the new tank, how to run the new plumbing, and how to reattach the shower seat. If you have any comments, please feel free.

 

[DougMai]

Here's photo 2. Can't seem to upload more than one picture at a time with my iPhone?

 

[DougMai]

Photo 3, looking at mock-up of longer tank extending into starboard v-berth locker.

 

[DougMai]

Photo 4, shower seat fitted over mock-up.

 

[Jim Legere]

I would recommend trying to coat the inside of the tank if you are determined to use Aluminum. Put an access hatch in the top and have the inside sprayed with truck bed liner (polyurethane) or coat it yourself with a coal tar epoxy. If cost is a factor, why not make your own out of fiberglass & West epoxy? You already have a mould with you tank mock-up.

 

[DougMai]

Thank Jim. If you recommend fiberglass over aluminum, then that's reason enough for me to reconsider. I was never comfortable with aluminum. But to be honest, I just don't feel comfortable building my own tank. As far as cost, it fiberglass and West System is doable. I will slow down and reconsider my options. More to follow.

 

[sandpiper10471]

Save some money and some toxicity. Build it with polyester resin and reinforce the panels with a bulker such as matline. A good glass tank should outlast an aluminum one.

 

[Tim M]

Doug, Have you looked into a pre-made plastic tank like a Ronco B415? It measures 39 3/4" and real close in shape to what you need - and twice the capacity of the original. Check out the other dimensions at tank-depot.com's site. By the time you add all the fittings it'll be maybe a little more than aluminum but will last the life of the boat. I'm a newbie to the forum but have owned boats and done boatwork for over 40 years and agree on getting away from metal for holding tanks. We bought a 37C this past summer and are slowly going through it for eventually living aboard and the holding tank looks like one of the things I too will have to address. Once I get the vent unplugged (the PO pumped everything overboard for 10 years) I will use the current tank but for extended cruising it is too small - especially with guests. Eventually I'll move everything to the starboard side - the deck outlet, the vented loop, etc. - and build a chase in the corner or the shower to accommodate it all and improve the smell in the v-berth in the process. Thanks for all the posts and photos and updates on progress, they're very helpful in planning for a similar project.
Tim M

 

[braol]

You could also just eliminate the holding tank altogether and install a composting/waterless toilet. They make marine/RV sized ones now and sell for decent prices...compared to a new tank and all the work. They're great for long distance cruising too because they, again, are waterless.

 

[frankies56]

holding tank

hello the po. that I bought the boat from probably had the same problem and his sulotion was to put a plastic tank under the laserette. well it kind fit side ways as it was to tall and never emtyed out .and smelled a little and my wife did not feel confortable sleeping over it I pondered any solution but went with a smaller poly tank that fit under the shower seat its five gallons but I closed up the space and use the locker now for storage and no more smell. bigger tank means more wieght and we dont go out long enough to fill it. and when we are far enough we just masecerate it out at sea.

 

[Ed Schenck]

I think your solution is a good one whether you use aluminum or glass. Many owners don't realize that early models like mine had everything on starboard as in your "alternative" drawing. Of course on the Great Lakes it is much simpler because the Y-Valve and pump are removed and the overboard thru-hull is plugged.

A previous owner had cut out the bulkhead and tank section leading to the v-berth in order to run hoses. Then he put a bladder in the center v-berth locker. I replaced that with a 22 gal. Ronco tank and new hoses. That project can be seen in Hunter Mods. Another owner put a 30+ gallon tank in that locker.

 

[DougMai]

Hello again. It's been months since I started this project so here's an update. I finally decided to build a custom tank using 1/4" fiberglass panel stitch & glued with West System. I decided not to go with a custom welded aluminum tank even though it would have cost less, been A LOT easier, and I'd been done by now. Though I regret that decision every time I sand fiberglass, at least nobody can accuse me of taking the easy way out.

Two photos of the tank in progress are attached. I followed stitch & glue advice I found online at 'this old boat'. You can see there are two internal baffles. I also added an extra 1/4" strip around the inside at the top to give more support and internal surface to glue the top to. After the top is on, I'll reinforce all external seams with fiberglass cloth and epoxy.

The top will have access port. I have worried over wether or not to include this port and have finally decided to do it.

Final step will be to secure the tank to the hull. I think I'll tab in some small supports for the bottom to rest on and then glass the top and bottom of the tank to the hull. These connection will be accessible and can be cut if the next owner needs to remove the tank. I'm not doing this again.

One more piece of advice to those who may want to do this project. The dimensions shown in my first measured drawing did work on my boat but the tolerances are pretty close. I got brave when building the tank and didn't exactly follow the mock-up. I was surprised how close I came to the tank not fitting! Lesson learned is that customizing something new into the boat takes a lot more care in planning and construction than following and original design.

I always enjoy all your comments. You can see that I was persuaded away from aluminum tank. I won't regret that decision after I'm done. My tank will be bomb proof. Thanks again for all comments and wisdom.

 

[DougMai]

Looking back, I see I never gave the dimensions for the new tank. I'll just tell you that I simply increased the length to 48" overall. That worked best with construction using a 4x8 sheet. Seems to have been the right length so far.

 

[Ed Schenck]

Good looking tank, nice work. Wish mine were new. Still original aluminum.

 

[Jim Legere]

Good looking tank, nice work. Wish mine were new. Still original aluminum.

Ed, I thought you changed out your holding tank for plastic?

Doug, you did an awesome job on the fiberglass holding tank. I still have the original aluminum tanks all round. Though I have no leaks (yet...) I am looking at ways to coat or line the existing water tanks and the holding tank.

 

[Amos Cape]

Poe 15 has very good products for lining your tanks. I haven't used that product but have used on my keel and has work great for five years now on my old S2 and three years on the Hunter 30'.

 

[Sailorjack]

Amos
What is POE 15 ?
Thanks
Sailor jack

 

[Jim Legere]

Amos
What is POE 15 ?
Thanks
Sailor jack

I think it is supposed to be POR15.
https://www.por15canada.com/