So i'm about ready to buy my first canoe. It will be either the SR 17 or 18.5.
Now which paddle? Well actually i picked out the paddle. The BB Sunshadow. The question is how do i determine length?
I've always just grabbed one at the outfitter never really paying attention to length.
I'm 6'4", long and lanky. Most of my paddling will be tripping.
Does size really matter?

Blade Shape
As with the other parts of a paddle, the blade shape that you may choose is affected by your makeup. How strong are you? How conditioned are you? The wider the blade, the more water you will be moving with each stroke, which provides faster acceleration and turns. In turn, wide blades force your arms out further from the canoe and require greater strength and endurance. Wide blades are ideal for shallow water and whitewater.
Narrower blades need to be longer to move as much water as their wider-bladed cousins. The less blade surface there is, the lighter the paddle is and the easier it is to run through the water. This requires a faster cadence and more strokes to cover the same distance. Narrow blades tend to have a quieter entry than wider blades. For longer trips, a long narrow blade is usually recommended.
Length
The length of a paddle is very important for comfort and safety. A paddle that is too long, adds extra weight and can cause shoulder injury. A paddle that is too short can cause difficulty with some of the strokes.
To measure the proper length of a paddle for you, sit on a chair and measure from your nose, down to the seat of the chair. This will give you the correct length from grip to throat of the paddle.The throat is where the shaft starts to widen into the blade.
Grip
You will be spending a lot of time with your paddle, so it is imperative that your grip is comfortable. Grips come in various shapes, such as t-shape, pear shape, straight (oar style), and ball shape. For long canoe trips, I recommend a smooth pear shape. As the grip controls the angle of the blade, I do not recommend the straight or ball grips. Grips are often weighted to balance out the weight of the blade to add more comfort.
The feel of of the paddle throat and shaft is also important. It should be comfortable to hold and not too thick. One who has smaller hands will need a shaft with less width. Likewise, one with larger hands will need a thicker shaft for a comfortable paddle.
Hope this helps you.
Canoe42

paddlingnomad,
Welcome to this site. It is great place to get information and find out what other people are using and doing in the Boundary Waters.
Canoe42

Great advice Canoe42, every thing you posted are excellent considerations when looking at paddles. I however don't fit the mold for paddle measurements. I have a real short torso and gorilla arms. I have a very nice paddle that is way to short for my arms having been measured in a similar manner. Another measuring method is to measure from your armpit to your palm and use this number for your shaft length. Currently I use a Carolina Carver bent shaft measuring 56". Custom ordered as the longest bent shafts readily available off the rack are 54". This paddle has a wide blade and everything said in the previous posting is accurate. I take long slow paced strokes and use the paddle face to get me down the lake at a slower cadence than people with narrower paddles. My buddy uses a very nice Beaver Tail paddle which is substantially narrower than my paddle but is also a longer blade. The result is we have about the same number of square inches of paddle face and subsequent paddling force. Just another consideration to muddy up the waters.

I would like to add an optional method to determine your paddle length. This is referred to as "This is a stickup" method. This method measures the appropriate shaft lenght and this regards the blade length. I think you will agree that you can have two 57" paddles, but depending on the blade length the shaft could range up or down by 4 inches or more.

How to measure the paddle: Grab the paddle by the grip and throat of the shaft, raise your hands over your head, make sure the end position has upper arms parallel to the ground and your elows form a 90 degree bend. The purpose of this exercise is to ensure that arms create box as you move through the paddle stroke.

Give it a try on your favorite paddle and see how this works.

My wife bought the bending branches Sunshadow for my birthday this past weekend. When asked by a friend if I had my canoe yet, i had to say no.

He replied, "so i guess you are up the creek with just a paddle".

For now i guess he's right. But when i show up next month with my brand new Souris River LeTiger the laughs will be over.
Still not sure Quetico 17 or Quetico 18.5.

Not all who wander are lost!
jay