I think that as smart as they are supposed to be it would definitely be a possibility, but at the same time why would they feel the need?
They don't fish, they can cross the river with ziplines and such, they only use wood from dead trees for crafting so it is probably a waste to use it on boats they don't need.
Also their size would make it difficult to combat currents if they were rowing, and sailing presents it's own challenges.
My guesstimate to add to the conversation, is that it is an underdeveloped technology in the Kypiq community to make and sail boats.