: I'm looking for various suggestions on building light/superlight s&g
: kayaks.

The kayak I've paddled for the last 10 years is 18 kg with all fittings, hatches and a heavy rudder. My latest was 13 kg when first sea trialed and 18 kg ready for multiday sea use - hatches, bomb-proof rudder etc. This means a 13 kg (30 lb) usable kayak is easily achievable.

My rudder and pedals could be considerably lightened - possibly 2-3 kg lighter.

Use 3 mm, light ply. DON'T glass the hull, only the seams. NO end pours - fit wood. 3 mm bulkheads. If you think the seat area might be stressed, spread the load with a hard closed cell foam seat bottom to fill the "V" with a softer bit of foam on top to actually sit on.

My 25 year old kayak is still used sometimes - no glass coating. All of my kayaks are used for multiday trips and usually hit a rock or two when out on each trip. Yes, I do have holes knocked in some of the hulls - by dropping from a height on to work bench corners, dropping (windblown) on to unprotected roofrack ends etc. but not from hitting things while at sea.

Alex