"Foam fixing" in water tank

[JeremyFowler]

More expert advice begged please...
I've had to remove my ss water tanks as there were slight leaks when I pressure tested them. (What a mission to remove all the cabinetry!). I now need to re-install them and was wanting to simply prop them in position and then fix them in position with the PU foam (from a canister). Is this likely to cause low-oxygen corrosion at the ss-foam interface? Or what other method should rather be used? Very difficult to make a permanent cradle as I need to first fit the seat supports after the tank is in...
Cheers!

[Cyrus Safdari]

There are ABYC regs about "cellular plastic"-encased metal fuel tanks but the same issues apply to water tanks - any sort of material that traps moisture or prevents oxygen against steel will cause pitting or crevice corrosion

Also not sure if the foam-in-a-can stuff is 1- open or closed cell: if open it will absorb water, and 2- how long it lasts before it breaks down and 3- does it have enough density to support the tank. The ABYC rules call for 2lb density foam like the 2-part stuff they sell for marine work