Hiya folks.

I have my trap off due to some necessary repairs and while I've got it off I am putting grip/padding tape on the side bars.

My question is; how rigid should the frame/ frame to pylon joints be. When the tramp is tight the frame is really rigid but there is a bit of motion between the corner castings and hull pylons. This seems to create a bit of twist through the whole boat. Is this desirable? Should I be shimming these joints to prevent this movement?

What do you guys think?

Thanks Pat

This is definitely not desirable. It is caused by two issues, first the pylon to casting gets loose over time, and second, the bolt holes in the pylon get "rounded" out and enlarged over time. Both will cause flex in the frame, and both are fixable.

The first issue is fixed by "gluing" the pylons into the castings with Epoxy. A lot of people do this to extend the competitive life of an older boat.

The second issue is fixed by restoring the pylon bolt holes and re-drilling them, as in the hotline issue below.

Here is a link to a Hobie Hotline issue addressing both:

http://www.w1dm.com/projects/HOTLINE/10-03-04%20HOTLINE.pdf

Welcome to the Hobie 16! Hobie racers have been trying to reduce frame slop in the Hobie 16 for decades. It's just part of the design where each corner casting has three individual parts that must fit together (or 12 total frame joints on the boat), there's bound to be slop. If the joints were significantly tighter, you'd need a hydraulic press to put the boat together. However, the corner castings on the newer boats were improved to help make the boats a bit stiffer. The old rule of thumb was that if you can raise one bow higher than a foot before the other bow starts to lift, your boat is too sloppy. If you're not racing, I wouldn't be too concerned about this. Just tighten the tramp as much as possible and sail. If you've got a really sloppy boat, the only real way to stiffen things up is to epoxy the corner castings. Coat them with release agent first if you ever want to be able to take the boat apart again.

sm

Thanks for the info guys.