Larry,

Not all fiberglass kayaks have hung seats. I used to own a New Wave fiberglass Cruise Control. The boat came from the factory with no seat at all, and I sculpted a seat out of minicell. The Cruise Control was a very stout and stiff kayak, with fiberglass, kevlar, and spectra in the layup. It would take a serious whitewater situation to collapse that boat.

The bulkhead would strengthen your Isere, but the hatch opening would weaken the boat. It seems to me that you would still need a rear wall in the kayak even with a rear hatch opening in the bulkhead.

For fun and interest, check out the link to PS Composites, who now builds the Jim Snyder designs. You can see the minicell seats, and the significant minicell walls in these composite boats. Makes me want another Cruise Control or Screamin' Meanie.

Chris