WATER TANK

[Killick69]

Whilst filling the water tank I found something else to do on Night Cap. She is a mark 3 with the water tank in the sole of the boat (above the hull). It is a glasses tank with round screw plug about 8 inch in diameter for filling. Noticed the ply which forms the top of the tank/floor of the cabin. has raw edges. The edge of the ply where the hole was cut is not sealed. Once the lid is screwed in the edges are in a moist environment. When sailing with a full tank, heeling will cause water to flow onto/splash onto the exposed ply edge. So far it seems no major damage has occurred, as the floor around the hole seems good. Has anyone found the same? what did you do?

I guess the best option is to drain and dry the water tank, and leaver the cover off for 2 or 3 weeks prior to the next slip. Then on the hardstand I can further dry the end grain with a heat gun and put on epoxy. Any suggestions on how to apply the epoxy sealer welcomed. Should I dry to syringe the sealer into the end grain or possible drill some holes into it from the edge??

Cheers, John

[storm petrel]

I put a 100 litre plastimo bladder in years ago, no more sloshing problems and nice clean water (with no fibreglass aftertaste).

Cheers,
Mark

[Tales]

Did the same plastic bag thing on Tales. No more problems.
Cheers,
Tom

[Miker]

Mark, Tom, did the plastic tank fit straight in the hole? Or did you have to cut the floor out first? What size/ shape did you get?

[Troppo]

John, I think it worthwhile for you to seal the ply edge with epoxy if you can. I personally would not drill holes in the edge to try and get the epoxy in but would give it 3 coats. This is what I would probably do:

1. Dry out wood as you suggest.
2. When dry, lightly sand off any surface loose wood and check that the build up of several layers of epoxy won't get in the way of the screw cap going back on.
3. Warm up wood with the heat gun as warmer means the epoxy will be more runny and soak in better, but it will go off quicker.
4. Use something like BoatCote epoxy with their TPRDA in the first coat as that inhibits fungi and stuff plus makes it very runny so absorbs better [first coat only with TPRDA]. Since it is only a small area needing doing, I probably would not use a brush but dab it on and smooth it with a finger, which of course is protected by disposable gloves. By using a squeezing/pressing sort of action you can force some epoxy into the wood. This works best on cracks to force fill them but some will go into ply end grain. After you go over the edge once with the epoxy, wait a minute and look carefully at the edge. You are likely to see where epoxy has been sucked into the wood as it won't look as wet as other areas, less sheen. So, rub on some more epoxy. Keep going over it if epoxy keeps absorbing into it. Takes a bit of time and fiddly but works well in my experience.
5. As soon as one coat has set but is still green then put the second on then the third. These coats go on much easier as should be no longer absorbing into the wood. Putting on a new coat before the old has hardened fully means no sanding between coats and they stick together real well. Three coats with the first one bonded very strongly to the ply and you should not have any problems with water getting into the wood. This is the sort of thing I do although I have not repaired my water tank.

cheers

Louis
troppo

[storm petrel]

Michael,

I put the bladder in years ago but I think it was the standard 100 litre plastimo from Bias, probably about 1m by 60cm or so. It is flexible so it doesn't have to be an exact fit, as long as it is in the ball park. I had an aluminium inspection plate about 15cm square in the old water tank for cleaning so I squeezed the bladder through that. I have not thought about it since. Though it is rated for 100litres it seems to fill with about this. This is probably because in my boat the old tank was divided into two sections and I just put the bladder in the back section which was larger and did not bother cutting out the divider. For the shorts coastal hops I do, 50 litres is ample.

Cheers,

Mark

[lockie]

I haven't resorted to a bladder for the keel tank in my Compass. But it's taken quite a bit of doing to get to where I can have nice clean water.

Here's what works for me:
Before filling, run the dock hose for a while to flush out the stagnant water.
Dose each fill with Davey Acquasafe (potable water tank treatment product) to keep the bugs at bay. Don't bother with bleach - it evaporates out very quickly.
Fit an activated carbon filter.
Use proper drinking-water plastic tubing.
Run the pump for a bit before you use the water for drinking/cooking, to get rid of the water that's been sitting in the tubing since you last visited the boat.
Don't allow even the tiniest bit of oil or diesel to find its way into the ank, as it feeds the bugs.
Don't expect the water to stay nice for ever - it needs to be used.

My water stays nice for about a month or 6 weeks now. After that, it's got a bit of taste but still ok for tea or coffee.

Cheers, Graeme

[Tales]

Mike,
The bag I bought from Whitworths was about the right length but too wide. I did try rolling up the sides but could only get about 30-40 litres in because of the trapped air.
I had the bag modified to make it narrower and can now get 50 litres in.
Cheers,
Tom