slight?
Do you happen to know what the Cd difference between, say, a typical spoon blade shape and a typical GP? I would not have thought it would be much greater than 10 or 15%. But I have no basis for this.
Good question
I bet the difference is in the range you mention, and will vary based on angle of the blades, shape, etc. But drag coefficient only tells the story of the drag-based component of propulsion. There will also be ‘lift’ for the GP, so the lift coefficient will also be relevant. I say lift in the sense of a thrust force perpendicular to the local angle of attack of the paddle. A component of that lift will act in the direction of travel, giving a thrust force to the boat. The lateral component of lift gives the tendency of the paddle to dive (or the boat to roll if the diving is restrained).
The drag force in that reference frame may also contribute to the thrust supplied, so I think keeping the term lift is valid, although lift is usually assumed to be opposed to the gravity vector. To the extent that a GP behaves as an airfoil section, the traditional lift and drag concepts remain helpful in the analysis.
gp cd greater
I would also think that for the same area the GP drag coefficient would be greater.
Wing paddles
I’ve been using them exclusively for years. I have no issues with joint pain using them. I have 3 wings, all different lengths and blade size. Depending which boat I use, then I pick the wing that is appropriate. I’m not a lilly dipper, speed and distance are my forte. I’m a very fit 63 year old.
cadence
I think of it like bicycling. If the goal is to ride for several hours, it’s generally better to spin a lower gear(less force per stroke)at a higher cadence than to push a slower cadence in a higher gear. That usually results in less muscle fatigue over time.
But on a long ride, I do like to vary my efforts, and will pedal standing in a high gear for intervals just to work different muscles.
When I go paddling, I usually take two different paddle sizes or types for the same reason. It’s nice to be able to 'change gears" depending on conditions, mood, or fatigue level.
As My Canoe Guru Would Say:
“Size of paddle blade only determines how much fulcrum you want to use.”
muscle memory
Found that I have difficulty planting the blades properly when switching back and forth from western to Greenland paddles inasmuch as I paddle the western with feathered blades. That is one issue. The cadence with the Greenland definitely needs to be a little faster, but it is easier in a long day paddle. One serious issue is when you paddle in shallow waters and are unable to plant the whole Greenland paddle. This can be frustrating because the few inches of submerged blade doesn’t come close to that of a western blade in like circumstances. I was one that switched from western to Greenland but still carry the western as a backup. However, using the whole paddle of the Greenland, with sliding strokes to correct steering, is an efficient way to paddle.
Skinny water with Greenland
I don’t find that my cadence is very different between a spoon, wing and my favorite Greenland paddles. Consider this: it’s not difficult at all to make a Greenland paddle that is too wide or too long and results in too low a cadence.
IMO what makes the GP so good for long distance is a variety of factors including technique. With good technique your GP blade will feel as solidly planted as a wing. The amount of lifting performed (combined weight of paddle AND arms) also plays a role. I have a blog post on this at http://www.gregstamer.com/2012/02/12/greenland-paddle-wing-paddle.
Handling skinny water with a GP is simple, use a very low stroke. A low sliding stroke also works well. With a very low stroke you can bury the entire blade in water six inches or so. You aren’t going to go fast in water that shallow anyway, unless perhaps you are Serge Corbin popping a canoe…
Greg Stamer