Basically a boat made of carbon fibre or inflated rubber (trampolines). Either immune to collision breakage, drops itself on collision, or repairable in the 2x2 grid.
A rubber dinghy is nice and bouncy, so would either bounce off on impact (doesn't break), capsize (drops itself), or deflate (drops punctured boat, repair with 1 rubber or resin). First step above wood.
A kayak made from carbon fibre would probably be lighter than wood or rubber, so would either deflect easily from an impact or capsize. Only breaks when punched or in lava. Due to reduced weight, possible minor speed and/or acceleration boost (around +10% at the most). This will be the top-tier one-man Steve-powered water boat.
Open to all suggestions, current recipes are 5/6 trampolines for rubber, 5 carbon plate (40 coal) for carbon fibre version.