Hi Martini,
We had one of these great boats. I think that ours was a 2001. 20 HP Yanmar diesel that would top out at 6 knots, then it's just pushing water so that's as "fast" as it would go.
Regarding the swim platform, I doubt that anyone makes one. The Hull is the same as the original Ranger Tug 21, the first series. Just open design instead of the Pilot House.
Due to the rounded back, it's going to be a custom made platform. There are lots made of teak that are custom made to fit your transom design so do a search for "teak swim platforms". Because these boats have a stern that tucks in above the water line, I suspect that the supports will need to be from the top, not the bottom like normal platforms. Also, I'm not sure where it will match up to the stern due to that "tuck". But take a look at the custom teak platforms. They are not all that expensive...Bob/Bradenton
