The techniques to stitch planks together are simple and effective but to cut planks back then would have been incredibly hard work.
Imagine a combination of 2 Log Boats with a raft across them, that would be easier to make than a planked boat, would be stable and give plenty of room for a decent load - the Neolithic Catamaran.
Would love to make one and transport a stone, anyone up for that?
ggd