Twice in the last 15 months we've thought that, and twice it's been the Plastimo flexible water tank housed in the forecabin. When the second one split, 13 months after buying it and one month after the guarantee expired, I decided enough was enough, and fitted a rigid tank.
A plastimo tank, around 70litres, designed for a boat was around £75, fittings extra. A Fiamma one, designed for a camper van was £49.95, fittings included.
These guys really know how to deal with us boating folk........
I removed the old tank, cut away the false floor supporting it in the locker under the forecabion berth and fitted a new floor, sloping to allow the water to drain to a lowest point. Louise painted the locker and I fitted the new tank.
Initially, it was not vented, until we realised that the resultant air lock stopped us from filling it. I then fitted a vent pipe, running it up to just below the deck filler for the main water pipe - figuring any water spilled, even when heeling, would be minimal. Perfect!
[caption id="" align="alignnone" width="300" caption="The new tank"][/caption]
The 'breather pipe'. I ran this from the top of the tank to a high point, near the water intake, just below decks.
[caption id="" align="alignnone" width="300" caption="Vent pipe"][/caption]