Sailors are always talking trash to Jarheads. It don't mean nothin'. I love paddling with open boaters even if they do flip on every little riffle and have to be constantly rescued and pick up all their gear and ferry them across the river to get their boats AND have to figure out how to tie these dinosaurs on your vehicle and still have room for kayaks.
The first real whitewater vessel was a canoe. Blue Hole came out with the Rolalex canoe back in the 70's. Kayaks were made of fiberglass back then so the Blue Hole was the do all indestructable whitewater monster. It only lasted a few years until they develope plastic kayaks (13 feet was a short boat).