Need to replace alumininum tank

[Scotian]

My 1973 tank is leaking and need to be replace on Northstar 500. (I have stopped using it and diverted fuel feed to portable tank for rest of season)
Problem is the moulded seats are such that it cannot be removed as one piece, To cut our area for one piece removal would make a mess of seats and the area.
Has anyone cut out their old tank or any suggestions as to how to proceed? I will need to cut from top and will only be able to cut seat out to within an inch or so of the edge of tank so will need to take it out in pieces. Access will be 13x13 to remove the approximate 14x14 tank.
If this is not possible I will convert a small storage cupboard and will install a custom made tank in that area next to existing tank.

Appreciate any suggestions based on other's experiences.
Thanks

[Don Moyer]

Scotian,

I'm afraid I don't have any suggestions, but to the extent that misery loves company, I'm getting ready to help our trusty webmaster cut two access holes in the top of his tank so that we'll be able to clean out the muck which has gotten so bad as to repeatedly clog his pickup tube.

Don

[Scotian]

I cut access hole in seat and see that tank is galvanized sheet metal. A fellow boater who works with metal says should be able to cut it out with tin snips so it may be a do-able job afterall..