I can tell you that the problem with this tramp groove on this specific boat is that they are split lengthwise, allowing them to easily spread apart. The tramp pulls downward and sideways on the groove and this spreads the split tubing to the point of splitting it in the bottom of the groove.

Look in that groove to find the lengthwise split and evidence of my gluing it. I desalinated it with water, dried it with alchohol and a warm air dryer before gluing it. I also pried it open to ensure good glue penetration. Once the entire split was glued, I clamped using a series of several rope wraps around the entire hull and a length of dowel to twist the rope to squeeze the slot closed. This was left to cure for 24 hours before being unclamped.

The result as a re-split on the glue line as soon as I applied my body weight to the tramp. The way the tramp pulls on the edge of the groove is much like the lever action of a can piercing opener like what was once used to open a can of beer before we had pop-tops.

I don't know if you'd want mushroom buttons on top of the hull because it would hurt your pelvis if you sat on one. I would not expect there to be adequate backing beneath the foam sandwich hull to support the buttons. I don't believe that mushroom buttons would be at the proper angle if you glued them into the slot.

The groove is probably unidirectional pulltruded fiberglass tubing. If that's the case, gaining strength across the section will be nearly impossible unless they are completely filled with epoxy or better yet, bridged over with a patch. Doug Sanborn and I brainstormed this problem and came up with the following solution:

A series of loops hanging out of the groove, with composite bandages bridging the slot in between each loop location. The loops should be Amsteel since metal sail slugs would fatigue from repeated flexing. Amsteel has the tension strength, abrasion tolerance to do the job. Take the largest size Amsteel that would allow you to fold it in half, tie the bitter ends into a knot that can be slid down through the slot and situated at each desired location. I think I tested a piece of 3/16" and a piece of 1/4". Can't recall which was the better fit. I seem to recall that 3/16" would probably be tight enough and 1/4" was a very tight fit.

The next step I am not convinced would be necessary but it would be to fill the slot with thickened epoxy.

Finally, take a strip or two or three of 2" or 3" wide woven glass cloth over top of the groove, in all the locations where there is not a loop of Amsteel in the way. You could use a layer of Kevlar cloth for abrasion resistance, followed by a top coat of fiberglass cloth.

I would mask the Amsteel loops so that they don't get any epoxy in the portion that will need to flex.

Those epoxy impregnated woven fiberglass (and Kevlar) "band aids" could be a single strip with a hole cut out for each loop.

Gary