PE Water Tank Mounting

[MCilenti]

Ahoy All!

Hoping for some advice on our latest project - We're in the middle of replacing the bilge mounted water tanks on our 1986 Bristol Channel Cutter.

The original water tanks were stainless steel and included standoffs welded on the bottom of the tanks. Obviously that makes sense to ensure the stainless isn't sitting directly on the bottom of the bilge and has some airflow to ensure the stainless remains...well, stainless.

We're replacing the tanks with rotomolded PE tanks (the same ones used by the OEM in later BCC builds). We were working on some supports underneath the tanks to ensure bilge water could freely flow. But, while conducting a dry fit, we noticed that both tanks there is room between the outboard bottom of the tanks and the bilge for water to flow, and since the tanks are plastic, there doesn't seem to be any need for an air gap like with stainless. Lastly, it seems like having the entire bottom of the tank on the bilge would provide the best support given the weight of water.

So...I'm scratching my head a bit and wondering if we should glass in standoffs on the hull or just rest the tanks directly on the bottom of the bilge.

We'd always heard that tanks need standoffs from the bilge so we feel like we must be missing something and look forward to your thoughts.
Cheers,
Mike

[MCilenti]

I wrote to Ronco and got this word back:
"You can have the tanks just sitting on the hull. Just make sure you have them secured down well enough that there is no movement of the tanks. If there is, it could eventually wear a hole in the bottom. If you can place something soft, rug, a piece of rubber under the tank, it will help prevent any rubbing."

Anyone have any experience with mounting PE tanks or thoughts?
Cheers,
Mike

[MCilenti]

Thanks Oliver.

Definitely great advice for the sewage system...another overhaul that's near the top of the list.

The current project with the PE tanks however is for the potable water system.

After what Ronco wrote we're leaning heavily toward NOT using any stand-offs on the bottom and having the tank rest directly on the bilge. We think this will provide the best support for the tank, especially given the weight of the water.

Of course, we'll still secure the tank very carefully so it can't move.

Any other thoughts and insights are most welcome!
Cheers,
Mike