: or any folding skinned sailboat of the 70es? Coo me for being lazy but I
: found my first sea paddling experiences exhausting after faring 3 miles in
: an afternoon. My yak was a Rath(er)burn(it): could this be the reason why?

If that 'Rathburn' was the type of folding kayak that scout troops often make -- about 8 to 10 feet long and about 32 inches wide -- then I suspect it was rather more like paddling an inflatable boat than an efficient sea kayak.
I have not paddled the Klepper myself, but I paddled along side one for a 50 mile trip. Or. perhaps I should say I tried to paddle along side one.

Of the 4 boats on the trip it was far speedier than any of the canoes. The husband/wife team in the Klepper would be more often resting and enjoying the scenery while we poor canoeists tried to catch up. I think the only time I got in front of them was on portages. My strip canoe was lighter than all the others, so as the trip went on and some of the food we carried was eaten, we could occasionally make a portage in one trip. The kayak was more awkward to portage. It was a late 60's or early 70's vintage Klepper and was on its second generation of owners.

Design of the boat is important. Look at aeronautics for a similar situation. A toy balloon will float if filled with helium, but try getting it to move forward in a straight line. A framed balloon, like a zepppelin, or a reinforced, but unframed, blimp will maintain a shape that permits it to be propelled and controlled, but even still, they are big, wide and greatly affected by wind conditions and air resistance. And then they are airplanes, which are much more streamlined.

I'd think of your Rathburn as being in the zeppelin catagory. I think you would find that something that is more streamlined would be far easier to paddle.

PGJ