[Public-List] V berth water tank

[George Dinwiddie]

Bill,

On 7/19/13 10:07 AM, Bill Newman wrote:
> My No. 233 is a non liner boat that I have owned for about 12 years.
> The water tank is fibreglass and is I believe, tabbed to the hull.

The usual arrangement is a tank that uses the hull and some laid up 
glass to form the bottom and sides. The top was generally a sheet of 
aluminum bedded and pop-riveted across the flanges of the sides.

The usual problems are that
  1. the fiberglas becomes saturated with water and slowly leaches into 
the water
  2. the aluminum corrodes, flaking white aluminum oxide into the water
  3. the pop-rivets start to leak

> Originally it had no inspection port so later I made one and found a
> very moldy plastic bladder inside the tank.  I removed this and
> thoroughly cleaned the interior of the fibreglass tank and used this
> for a few years until it began to leak.  I then cut a larger opening
> into the top and installled a bladder which does not conform well the
> the shape of the tank.  If it is completely filled it bulges out the
> opening and leaks some water no matter how well the fittings are
> tightened.  The result is that I cannot carry a lot of water with
> this arrangement.  I do not use the tank for drinking or cooking just
> for washing myself and the dishes.  I am thinking of temporalily
> removing some of the furniture from the v berth, then making a
> cardboard mock-up of a tank that fits the space and taking this to a
> tank maker to have it fabricated.  I am thin king of having this made
> of aluminum because there are several companies who will do this and
> a mold is not required.  I expect my experience is not unique.  My
> question is. has anyone had any experience  replacing the water tank
> under the v berth and if so any advice or information about how to
> proceed and the results will be much appreciated.

I would not recommend using aluminum. Like the original aluminum top, it 
will oxidize and flake white aluminum oxide into the water.

The usual fix for the water tank is to
  1. remove the furniture
  2. remove the top of the tank
  3. clean the tank well
  4. coat the fiberglas walls with epoxy
  5. put on a new, non-aluminum top (high-density polyethelyne or 
reinforced epoxy sheet) bedded with good caulk, and using self-tapping 
screws instead of pop-rivets

If you do this and add a charcoal filter, you should have water suitable 
for drinking.

Of course, you still need to clean the inside occasionally through a 
port on the top, and you may want to dose with chlorine (plain chlorox) 
when you fill the tank.

  - George

-- 
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   When I remember bygone days                         George Dinwiddie
   I think how evening follows morn;            gdinwiddie at alberg30.org
   So many I loved were not yet dead,           http://www.Alberg30.org
   So many I love were not yet born.                          also see:
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