There is a 16 for sale near me but where the pylon (post) heading up to the right rear corner casting (frame on the aft starboard) is, the "connection" is real loose. the front connection on that side is loose too. It looks like the same thing happened on the port side but the owner has blasted it with rivets. There's a bunch of extra rivets on the bad side too, but (without taking things apart) I suspect the bolt connecting the pylon to the corner casting has wallowed out this area. I can't fully assess if the connection of corner casting to front and rear beams and to the sidebars is loose, but lets assume that is the case as well.

Otherwise the boat looks pretty good. Has anyone fixed this with a durable repair? Any advice appreciated...

maybe you could epoxy the boat together by putting a jb weld type epoxy in all the metal to metal connections while the boat is sitting "square". people that do this regularly have a jig to keep the boat aligned while the glue dries.

recommend posting some pics

that's a pretty important area and while it could easily be bodged together it would be false economy if the boat broke up while you were doing a screaming reach in the open sea

The short answer is yes.

It's unclear from your post whether the pylon is loose inside the hull (difficult fix) or just loose in the corner castings (easy fix).

A search here, the Hobie 16 forum or the Hobie Community Forums (www.hobiecat.com/community) should turn up methodology for both fixes.