Thanks Randy.
AK- been replacing the transom this winter, 2001 Lund, I did find a very small area of water logged foam in the very back (at the very bottom, maybe the bottom inch), but was contained within the transom to (not quite up to) the first cross member (so about 6-8″ inward). Aluminum was pristine though near that insulation, couldn’t say the same about where the rotting transom wood was touching the hull. Boat stays inside except when being used though so that surely helps. Since I like to do things backwards I redid all the interior last winter and had the floor up, all that foam was ‘like new’. Boat never has noticably taken on water aside from the time I put the livewell intake pump back in without the o-ring on accident.