Xytec repair (Sun kayak)

I have a Sun Flight kayak with damage to the edge of the cockpit. I’m looking for advice on repair materials and methods. The kayak is made of Xytec. Thanks.
I’ve attached a photo.

A picture of the damage would be good, Delia.

I added a photo. Thanks for the reminder.

Drill a small hole at the end of each crack or the cracks will continue to grow. Then you can either try to plastic weld them or use something like g-flex epoxy to repair it.

I am not familiar with Sun Flight kayaks nor Zytec. Started by googling Zytec, and only thing I found was a sperm donor web site, so that didn’t help. But did find some photos of the Sun Flight kayaks, and 90% sure they are some form of polyethylene (looked that way in the photo you enclosed also).

PE plastic that cracks like that is usually due to the plastic aging and becoming more brittle. Sun exposure speeds the aging.

Good news is PE is repairable with plastic welding.

Bad news is that these repairs are generally not that strong (less so the more the plastic has aged), so if you apply pressure (such as by pushing down on the combing as you enter/exit the kayak, as usually happens), your repairs likely will re-break. Maybe try not just welding the cracks, but adding another layer of material on top or bellow the crack for strength.

Thanks to the Way Back Machine, I see that Sun Kayaks was a line of rec/touring boats from Riot back in the late 90s - early 20s. Unfortunately, there is little info about Xytec except that it’s a proprietary material and, shockingly, is fabulous. It does say that Sun boats were rotomolded, so Xytec is some sort of polyethylene variant, probably a linear poly with a higher density than the norm. High density poly (HDPE) makes a stiffer hull; it’s also more durable and less prone to heat deformation. However, it’s also susceptible to stress cracking. HDPE is notoriously difficult to glue, but it can be “welded”. I have no experience welding poly, but others on this forum do.
More info on HDPE repair can be found here:
Good luck!

It is unclear if the OP actually uses the combing to secure a skirt to the kayak or uses it just as an open cockpit.

The cracking if you blow up the photo looks like a more brittle material than we are used to and also the top of the combing looks like a perfect straight break like it was molded in two parts and bonded.

To a large degree the repair will be only as strong as the materials and process used, and with the material being an unknown some experimenting would need to be done.

I would be tempted to do a mechanical splint on the inside and some fasteners thru the combing and hull and then something over that for some strength and mostly cosmetic. That repair would be up to the OPs skill levels at forming a brace/splint from say aluminum and having the skills to bolt/rivet it into place.

The crack looks like the strap holding it was tightened a bit too much; maybe even a ratchet strap.

If you repair it with a plastic welding rod it will be weaker than the original, so be careful with it.

The rest of the plastic looks like it was well treated and in good shape’ so welding it will not be a problem. Make sure to find a tool that can make the crack into a V groove, so the weld has the most area to hold on to.