The old swim platform was pretty rotten and literally fell to pieces when we took it off.

We decided to build a new one from ribbed, treated deck lumber.

It was much harder than anticipated to get the curvature correct, the swim platform’s frame is not entirely symmetric. But finally with the help of a piece of cardboard/plastic as a template we managed. You can see that it’s home built but thats fine. The boards are screwed on from the underside with acid-resistant (A4) screws.

Looks great! I wish I had a swim deck frame at least to do as you did. Unfortunately my boat doesn’t have one…yet.
Thanks! Yes that did help quite a lot, wouldn’t know where to start if there was no frame from before 😉