Bass Tracker question on foam replacment

[TNFISH]

Hello folks, this is my first post and first time working on a Bass Tracker. I have gotten a lot of useful information on this site over the years but could not find the answer to my question. I'm doing some restorations on a Bass Tracker I purchased at a great bargain but didn't really need. It has sat for two years without me touching it and now I'm ready to use it or sell it but I'm fixing it up first. I had a mechanic come and check out the motor tune it up and it runs strong. I'm replacing the decking one section at a time. The foam under the rear casting deck has expanded and buckled the aluminum floor popping a few rivets. I drilled out all the rivets holding that section down, the foam under the decking is dry. I thought I would remove that section of the deck, remove some foam, rivet it back and then re-carpet. It's the left side of the boat and there is a hose going from the live well through the foam into the bilge area so it looks like I have to dig that hose out in order to remove that whole section of aluminum deck in order to remove the rest of the foam to get the decking flush and level. If you are still following me please correct me if I'm going about this the wrong way.
My question is since my foam is still good and I'm going to have to remove more foam than I initially though just to get the deck level. Is I OK for me to leave what is still good once I get that section of decking out and pour new foam on top of the old foam? Or do I need to remove all of the old foam and go new all the way? I hope all that makes sense. I'm going to attach a few pictures just so you guys have a better idea of what I'm working with. Thanks in advance for all your help.

 

[jigngrub]

I think once you start digging into that old foam you'll find that it's wet and all of it needs to be removed.

I suspect the wet foam froze and that's what make the rear deck buckle and pop those rivets when the frozen water expanded.

 

[TNFISH]

Well it has defiantly been left to the elements but I have dug all the way to the bottom of the foam and back about two feet accessing it thru the hatch behind the passenger seat and its solid. I worked on it about two hours the other night and got most of what I could reach with a reciprocating saw and chisel. Still a lot left in there, I'm working my way back to the stern. I looks like I'm going to end up taking most of it out in order to get that panel off, unless I cut it on one side and I would rather not do that. If I get most of the foam out and the panel off would it be OK to put new foam on top of the old foam? Since the foam was supporting the deck I figured I would fashion some additional bracing, add some foam, rivet the decking back and then top the foam off by pouring thru a hole that is already in the decking to create a nice solid structure. Does that sound about right??

 

[TNFISH]

Well it has defiantly been left to the elements but I have dug all the way to the bottom of the foam and back about two feet accessing it thru the hatch behind the passenger seat and its solid. I worked on it about two hours the other night and got most of what I could reach with a reciprocating saw and chisel. Still a lot left in there, I'm working my way back to the stern. I looks like I'm going to end up taking most of it out in order to get that panel off, unless I cut it on one side and I would rather not do that. If I get most of the foam out and the panel off would it be OK to put new foam on top of the old foam? Since the foam was supporting the deck I figured I would fashion some additional bracing, add some foam, rivet the decking back and then top the foam off by pouring thru a hole that is already in the decking to create a nice solid structure. Does that sound about right??