Brace yourself, these are how my decks are built. You can see the unturned deck flange on the left side. After all the fastening was complete, it was taped and glassed again. This worked well to keep deck water out of the cabin. But it doesn't do anything about water moving all over, once it gets behind the trim piece, which happens at various rates depending on the success of the bedding. It weeps from fastener to fastener, and sits in there, never drying out until the piece is pulled.

And as the years went by, it became harder and harder to seal that trim piece(all surfaces have to be perfect and well sealed as you know).

Many of these Challengers have lost their bright cabins to paint. This area is the achilles heel. They get repaired and glassed and painted. They still look good but I'd really like to preserve this cabin long after I'm no longer the owner.

My friend at RM says even in the best case scenario, sealing 40 so feet of trim is a crap shoot. And I store outdoors which adds more difficulty. It's been a rewarding project and if it works, I'll be pleased.