Wayne,
You must consider maintenance, so an access hatch will be needed for each
baffelled compartment. I use studs, nuts and make-a-gasket RTV for the seal.
The boat layout will determine where the inlet and outlet ports should be.
Here, I suggest flanges, studs and gaskets or RTV. When all assembled, test
at 2 psi for 24 hours. I take special care with dissimliar metals and if I
have to use them, I use nylon isolators and tophats around the bolts and
studs. Always check with a VOM to be sure. However, do not use these with
the fuel tank. (static). Dissimiliar metals only matter when wet. No water,
no ploblem. I would be concerned about chafe between the hull and the tank.
Either eliminate the problem by bolting hard to the hull or use rubber shock
mounts and use a bond cable across a mount for earth.
Steve

"Wayne.B" wrote in message
...
On Sat, 5 Jun 2004 19:47:57 +0200, "Steve Lusardi"
wrote:
As a cost, I would estimate $3000 to $4000 per tank would be
close.

Thanks for the information, estimates are close to what I've received.

The realy BIG costs are removal and re-installation - holes to be cut,
reglassed, painted, etc.

What do you use for fittings, and do you take special precautions to
isolate dis-similar metals?