not broke?

Posted by LeeG on Jun 17, 2004

A 3' crack is more descriptive than "broke". 4yrs ago I took CLCs staff out for rescue practice before the existing deck glass/hatch reinforcemts and two aft decks "broke". The specific damage was a sheer to sheer hatch strip breaking away (poor gluing job similar to some beginners boats I've seen) in conjuction with the aft hatch ribs pulling away from the underside of the hatch. Those two things allowed the aft deck to flex up/down about 2" with the hatch almost going concave then popping back into position when the weight was off. In rough conditions that is guranteed to pump water in/out with a person attempting a rescue while climbing on the aft deck. It was the original LT16 which actually had a standard aft deck curve but lower side panels,,the other one was the WR180. There were other boats with no problems but 2/6 is not a good ratio for flat water rescues. So in that original configuration of no deck glass and only two sheer to sheer under deck hatch stiffener a LOT was riding on the strength of that ONE strip and the sufficiency of the glue joint on the underside of the hatch at the end of the hatch ribs. With a heavy person and rough use those two weak spots could result in the aft deck flexing up/down as the edge of the hatch ribs pulled away and the unglassed area behind the cockpit dealt with a fat body (or not fat) scrambling to get back in. So even with the aft bulkhead, rigid coaming and deck curves, (LT and WR series have nearly flat aft decks) 4mm plywood can be stressed when a 200lb body throws itself around. That's why when I made a Ch18 for 250lb +paddlers learning to do rescues in classes the deck had 6oz glass, the underside of the aft deck had two layers of 4oz from cockpit to hatch with 4oz after the hatch, and the hatches were recessed. A 275lb person tossing themselves on a big kayak shouldn't hear cracking sounds,,,and there weren't in three years of use with some 300lb+ paddlers.

Thereafter those original demo boats got deck glass and/or hatch hole reinforcements. Like a fiberglass kayak there are some areas where the kayak can be "damaged" and not have any safety consequences other than waterstains, or in the case of a fiberglass boat gelcoat cracks. There are other areas,,like the pre-reinforcement set-up where an aft deck/hatch that could flex up/down 2" could compromise flotation in a rough water rescue. The problem with nice light absorbant Okoume is that beyond a certain amount of flexing you'll get tiny microcracks that allow waterstaining and although nothing is really "broke",,,your 7coats of varnish are for naught. It's possible to make it strong enough for any use without getting excessively heavy. You just gotta know where the stresses will occur.

In Response to: Re: Broke my chesapeake 1 by John in Dallas on Jun 17, 2004