Water tank installation

[Val]

I am replacing an old aluminum water tank with a 42 gal. Ronco plastic tank which will lie along the hull about midship. Side of tank facing hull is flat and hull is curved so tank will contact the hull at 4 corners.

I plan on using 2 part foam to fill the gap between tank and hull but my question is do I need to be concerned with hard spots at the corners and reinforce or cushion the hull at these points? If so, what would be the best way?

Two options would be to build up a circle of a couple layers of glass or glass in a piece of hard insulation foam.

I could put enough 2 part foam under the tank to keep the corners off the hull, but
I am not sure how much the 2 part foam will compress over time.

Tank will of course be tabbed in and strapped down to prevent movement.

I plan on keeping this boat a long time.
Thanks for any input.

 

[Cap't Ron]

bought into it?

If not consider a bladder tank, these are easy to install, secure and remove + an added advantage is you can use part of the skeleton of the old to set it into.

Not a good thing to have anything rubbing against an FRP hull, but entirly possible to use some material as a buffer.

Did you check with the Ronco people? They have pretty good input as to ABYC rules and are an excellent company.

 

[Dave]

Support the tank!

I have a RONCO tank under the V-Berth in my Catalina 38. The aft bulkhead, where the tank is mounted, warped and the wall of the tank was no longer supported against the bulkhead. The tank bowed out under the pressure of the weight of the water and the top of the tank and the tank wall actually tore apart. There is a break along the top edge of the tank that leaks when the tank is full. If You do go with the plastic tank, be sure that all edges and large flat areas are supported or enclosed enough to prevent such bowing. There are few if any adhesives that will seal and bond this plastic against pressure or strain. I am now faced with bringing in a plastic welder to try to repair the tank. It is built into the structure beneath the V-berth.
If you use a bladder tank, be sure to provide a smooth non-abrasive surface with no sharp angles for it to lay against or on. We had a bladder tank in a previous boat for our diesel fuel and after years of use it chafed through where it folded up against a stringer and we had a slow fuel leak that took a while to find and an even more difficult task to reach oily spaces to clean.