1989 Sea Nymph FM146-20 project

Hello all. New member here with a 1989 Sea Nymph FM146-20. I picked this boat up a few days ago in order to have something inexpensive for my kids to use but have some work to do before I set them loose in it. The boat was advertised as needing new gunwales and flooring (the existing stuff was already out). This was fine as it gave me a chance to inspect much of the aluminum that's normally hidden. I didn't really find any evidence of corrosion so I pulled the trigger and brought it home.





The boat was last registered in '94 and had been sitting open for some time. After looking it over a bit more closely I found 3 small pinholes on the outer skin of transom in the area where the core is. With that in mind, and the deteriorated state of the foam, I decided that I needed to gut it, check for additional corrosion, refoam and most likely put in a new transom core. The existing core doesn't seem shot but if I'm going to be in there I might as well just do it.

Here's where I need a little guidance. The inner skin of the transom covers the entire core (top to bottom, side to side) and is riveted and/or bolted to the hull sides, side interior panels outer transom skin. How would you guys recommend I pull the transom? The way I see it, I have two options:

1. Remove the rivets in the top portion of the inner skin that wraps over the core and on to the outer skin. Cut off the folded over portion and expose the top of the core. Remove the bolts that run through the core (and hold the transom handles) and slide the core up and out? Reassembly would only involve riveting or bolting a piece of AL u-channel across the top edge of the transom.
2. Remove all the rivets and bolts in the outer skin, sides, etc so I can pull out the inner skin and core as one piece? This would give me much better access to inspect the inside of the outer skin. Rivets removed would be replaced with new closed end rivets when it came time for reassembly. I feel like this is the right way to do it.









Thanks.


Brian

Also had a couple of questions centered around the floor and gunwale rebuild.

1. In the interest of trying to move the project along quickly and keep the overall cost down, I think I'm going to use exterior ply for the floor and just apply several coats of a quality oil-based primer and paint.
2. Has anyone considered using or used PVC board in their rebuild? I think it would be cost prohibitive to use on the entire floor, but might be good for smaller parts like the gunwale covers.
3. Has anyone ever considered using or used aluminum or stainless nutserts/rivnuts to mount their floor? In theory these would allow repeated use of the same mounting holes.

I'm sure there will be more to come as this is my first aluminum boat and I've got a bit of learning to do.

Thanks.