I have occasionally seen pictures or description of canoes and kayaks which have their greatest beam aft of midships. This makes them very pretty, IMO, but are there any advantages to building a kayak with this shape? I have also heard of kayaks with the greatest beam forward. Same question? in a kayak with these shapes, do you move the position of the paddler accordingly?

All the boats I have paddled (mostly canoes) have been symmetrical.

Thanks in advance.