Thanks..good advise..whats the worst that could happen..i blow myself up or cut thru bottom of boat...

https://www.facebook.com/photo.php?f...type=1&theater

I don't think you will do that
 

Follow the advise of the poster before me on how to cut the floor board and you'll be fine.

The only bilge water that should be running beneath the bottom area of the new tank should be through a 3/4" pvc pipe......Before anything, a 3/4" pvc tube or pipe should be placed low in the keel area between the bulkheads glassed in and sealed in place.........the tank will go in next making sure to leave enough room on all sides for the foam to expand and encapsulate the tank totally .........I did this on my Mag sport with 2 belly tanks on either side of the keel stringer.

Make sure you paint the new raw aluminum tank prior to installing it to help protect it against corrosion.

I just did mine in my pantera. 65 gallon. The original wasn't leaking yet but it had lots of pitting and was just a out to spring a leak. I replaced it while I had the boat apart for restoration. I figured I should cut the floor out and replace it and I'm glad I did.

thanks for advise guys really appreciated..

if you get a tank from speedy tanks it comes coated .

just read your thread, have you considered a rubber bag tank/ safety cell. ATL make to order marine versions and you can use the existing sides and base of your tank as the container.
Its not cheap but could save u hours, avoid cutting the boat about so much and 1oo% safe, all the serious race car boys use them and many top line boats. May be worth looking at.

ok floor is out tanks is super tight to stringersand foamed in..it aint budging any tricks to get it free???

Not sure what it is and maybe someone else can come on board and confirm.

There is a solvent that will disolve the foam. Again not sure which solvent it is.

Bread knife works good to cut out the foam.