Water Bladder

Marshall Wright · Post by **Marshall Wright** » Wed Oct 03, 2007 10:36 am

Greetings,

I have decided to install a water bladder in my existing leaking watertank and need a lead on a company that might make one up in a custom size.

The original tank was built into my boat, under the sole -- or is that soul? Ive given up on removal/replacement-in-kind as it would entail removing flooring, my table and benches and cabinets, etc.... This also gets under my bulkheads and under mast support post. Too much for me to do and ever put back together nicely.

I've looked at the available sizes of bladders from Nauta and Plastimoand they are too small, too square or too big.

Does anyone know of a bladder company that might make one to a custom size?

All leads or advice appreciated.

Thanks in advance.

Marshall

CharlieJ · Post by **CharlieJ** » Wed Oct 03, 2007 11:21 am

Have you looked at Vetus? They have some triangular tanks and maybe other shapes too.

Figment · Post by **Figment** » Wed Oct 03, 2007 2:26 pm

What's wrong with a bladder being a bit too largefor the space that contains it?

Marshall Wright · Post by **Marshall Wright** » Wed Oct 03, 2007 8:08 pm

I guess I was worried that all the bunched up material would significantly reduce the spaces storage capacity.

deckhand · Post by **deckhand** » Wed Oct 03, 2007 9:10 pm

what exactly is the advantage of the bladder? I understand using one as temporary liquid storage that can be folded away when its used up, but since it's going inside a tank what's the point? If you can get a bladder tank into that area you can probably get a paint brush full of epoxy too. Then again I'm speaking from a point of never have seen your set up so maybe I'm completely off base here.

If you can't find decently priced bladder tanks, you might want to consider making them yourself. Vinyl and vinyl composites weld together really nicely with their vulcanizing/chemical bonding glues. Just make sure you apply a bunch of pressure when the glue is on. I used a radio welder a while ago for vinyl but thats like killing a fly with a bazooka. You'd make all your angles and stuff out of copper or bronze, cover it with teflon fabric and, bzzzzzt! your two pieces were one!

Quetzalsailor · Post by **Quetzalsailor** » Thu Oct 04, 2007 9:13 am

I used a bladder in a Morgan 27. The original plastic tank could readily have been replaced, so no real excuse. I placed it so that it would not be continually flexing as the boat moved. I arranged it so that I could take it home each winter and store it dry, as well as wash it out in the spring. (I used a bladder for the black water, too; rest assured that I did not take that one home!)

In any case, if you can get a bladder into the existing tank, can you not fix the existing tank? Probably not, if it's the rigid polyethylene, but if it's integral fiberglass or aluminum, possibly so. By the time you hack a big enough hole in the top, you'll have pretty good access. And you don't have to fix the hole; install a deck plate.

Marshall Wright · Post by **Marshall Wright** » Thu Oct 04, 2007 11:57 am

OK, some interesting suggestions here.

Some background first. The tank is so built into my boat that my boatyard (Hinkley mind you) doesn't want to do the job. The nearest open-ended price I've got to replace the tank is $8000.

I do have an access panel which exposes about 12" of the watertank's end. The rest of the 4' tank is under the floorboards, bulkhead, etc. I have a 6" plastic access port in the tank top right at this point and was going to either cut a larger opening or push the bladder through this existing opening. I thought I'd keep the existing tank to stabilize the bladder.

The tank is metal, has several holes it its bottom but otherwise is firmly built-in.

Question- Can I epoxy the tank's interior and use it as a watertank? Would the water be safe to drink? I could cut out my existing port to give me more arm space and use a wood pole to slip and position matting into position. I wonder if once positioned it would stay in place? Final step, repair the top and cut in another port?

Is this what you're envisioning? If so, what kind of matting and epoxy would be safe?

I'll do this if you think it is an option.

Marshall

CharlieJ · Post by **CharlieJ** » Thu Oct 04, 2007 2:14 pm

after reading that I think your idea of a bladder tank is a good one. I have a friend who lives aboard a Seafarer 30 in Florida who had the exact problem- his tank was damaged ( Hurricane Ivan), the cost to replace was horrid, so I suggested he fit a flex tank inside it.

He did that and has happily lived with the results ever since. I don't think he lost all that much capacity either- the flex tanks just kinda "fill out" the space they are in, with in reason of course.

I added a second water tank to our boat, in a previously unused area under the cockpit sole. We are delighted with it and once a year it's quite simple to remove it and flush it out at home.

Sounds like a viable alternative to me.

deckhand · Post by **deckhand** » Fri Oct 05, 2007 1:35 am

Now that I've heard more, I agree that a flexible would be a better move. I'd just make sure the corroded holes aren't too sharp.

Quetzalsailor · Post by **Quetzalsailor** » Mon Oct 08, 2007 9:29 am

Yes, you can drink out of epoxy-coated tanks, or tanks made out of epoxy laminates. Gougeon's book tells you how to make a water tank. You can also drink out of polyester tanks, common on older boats.

Clearly, yours is a candidate for a bladder since hanging upside down and working with epoxy and not having Inspector Gadget arms would be impossible.

I'd bore some dandy large holes in the bottom of the tank and clean up the raw edges. Then I'd lay a piece of Enkadrain on the bottom to ensure drainage. This will reduce wear on the bladder and help keep smelly mosses from growing between the tank and the bladder. I laid my water and black water bladders on this stuff and the boat no longer smelled awful. (Enkadrain is a non-woven mat made for conducting water down foundation walls and from under plaza paving. Get an architect or engineer buddy to ask Enka for a big enough sample).

I think you'll be cutting as much out of the tanktop as you can: for access for cleaning and assembly but also for routing the fill and drain. The drain does not move much but needs to not impinge upon the tank (I ran mine under the Enkadrain. It's the hose clamps that could damage things) The fill has to follow the bladder up and down as the tank is filled and emptied and it's pretty stiff.