Holding tank removal from pour foam insulation

[wade the giant]

My factory installed holding tank has failed. The welded threaded fitting has cracked and the tank itself has a lot of calcium at the bottom so it’s time to replace the tank. However, the tank is really hard to remove because of the pour foam. Any recommendations on how to remove the tank? So far, I am using two machetes… it’s a shitty situation.
thanks
-wade

 

[Captain Larry-DH]

You can replace that welded threaded fitting - Peggie Hall probably has a solution. Contact her before you destroy what you have.

 

[wade the giant]

You can replace that welded threaded fitting - Peggie Hall probably has a solution. Contact her before you destroy what you have.

thanks for the advice, but whoever tightened the attachment fitting, screw it in too tight which caused the crack and the sewage to spill when it fills. There is sewage underneath the tank and in the foam.

 

[Peggie Hall HeadMistress]

Even if the fitting weren't leaking, the only solution would have been to have a plastics fabricator remove and spinweld a whole new fitting (everything you see in his second photo) and you wouldn't be able find one that'll touch a used waste tank.

_Peggie

 

[wade the giant]

Even if the fitting weren't leaking, the only solution would have been to have a plastics fabricator remove and spinweld a whole new fitting (everything you see in his second photo) and you wouldn't be able find one that'll touch a used waste tank.

_Peggie

Peggie, thanks for taking the time to respond and for educating me on terms. I spent hours using two machetes and a pocket knife to remove one side of the poured foam and success!! I wiggled the tank free. I agree about the foam. It is unnecessary to foam in holding tanks.
thanks again

 

[Tally Ho]

Looks like you need some leverage to pull the tank out of the foam. Could you drill a few holes in top and side on 4 corners and get some rope threaded thru the holes, and use them to pull the tank up?
I assume you can't pull on the hoses/fittings enough to break it loose..

Greg

 

[Peggie Hall HeadMistress]

Peggie, thanks for taking the time to respond and for educating me on terms.

I love sharing what I've learned over the years 'cuz none of us were born knowing anything about boats, much less all the terminology...and I still continue to learn. Your boat's PO taught you a very valuable lesson that most boat owners have to learn when a fitting on a tank they want to keep cracks: don't over-tighten them!

--Peggie