Bent Shaft Paddles
Once only found in the domain of the marathon racer, these efficient paddles have gained popularity in recent years with recreational paddles. Long hours on the water make every technical advantage a windfall. In my experience with both types of paddling, I wouldn't use anything else.
The bent shaft paddles are excellent shallow or deep water paddles that offer increased efficiency. The blade of the paddle is offset from the shaft to allow the blade to remain vertical to the canoe's path throughout the stroke. This improves the efficiency of each stroke and allows shorter strokes at an increased stroke rate. These factors coupled with a 'sit and switch technique' (changing sides every twelve strokes or so), make bent shaft paddles hard to beat for long distance paddling.
The bent shaft paddles are excellent shallow or deep water paddles that offer increased efficiency. The blade of the paddle is offset from the shaft to allow the blade to remain vertical to the canoe's path throughout the stroke. This improves the efficiency of each stroke and allows shorter strokes at an increased stroke rate. These factors coupled with a 'sit and switch technique' (changing sides every twelve strokes or so), make bent shaft paddles hard to beat for long distance paddling.
Straight Shaft Paddles
Traditional paddlers often like the Beavertail and Voyageur designs which use a straight shaft. Paddlers in the stern of big canoes, also use straight shafts paddles of a modern teardrop design. Personal preference is also important here, as many paddlers have grown up with a straight shaft paddle and feel comfortable with one.