-- Last Updated: Sep-23-12 12:06 PM EST --
I'm very late to this discussion as I was doing long overdue house cleaning instead of looking at paddling.net.
I made a Baidarka at the Skinboat School in 2003. I test paddled a number of different size Biadarkas in the bay to determine what size I should build. During those trials I used an Aleutian paddle. After those trials, I told Corey that it would take me a while to become comfortable in narrow Baidarks (the one I built is 19" at the water line with substantial flare above) but I absolutely wanted one of those paddles; I found it that impressive! I had only read about Aleutian paddles, and never seen or tried one before. The paddle I made at the Skinboat School in 03' has been the paddle I have used for 95% of my paddling in the nine years since. The rest of the time I use a GP.
Anyone can formulate a argument for anything and it frequently is done on internet forums: you argue "A" and I therefore argue "B". The question of which face is the power face on a Aleutian paddle is a case in point. My opinion is below.
When viewed from the side (with flat side down), an Aleutian paddle has a taper. The taper starts on the ridge side at loom and runs down to near the bottom (side view) of the nearly flat bottom side. The taper is the thickness of the loom minus the thickness of the paddle tip. This taper means the paddle is partially ahead of the hands in use (ridge facing paddler), promoting stability from this orientation as well as from the ridge. If used with the ridge side forward, the same taper would place the paddle partially behind the hands, promoting flutter if used in this orientation.
I was told this is how to hold the Aleutian paddle and now believe it from my 9 year experience paddling with an Aleutian paddle. This "theory" further was tested in late May when a powerboat wake threw my full weight onto an Aleutian paddle just as I was bracing while getting out of my kayak. That paddle, constructed to Renzo Beltrane's plans, is less stout than the bombproof Skinboat School paddles (with a sitka spruce core). The paddle cracked lengthwise on the power face. The crack starting on the surface nearer to the tip, becoming deep under the ridge as it approached the loom. There was no spare paddle among the 20 or so on the trip-lesson was taught. To get back to to the launch site, I had to paddle with the flat face rearward (backwards) to have water pressure close the crack as I paddled. The crack would have opened and maybe the paddle broken if I had paddling with the ridge rearward, considering the bad crack. When I reached the launch site after paddling holding the paddle backwards, my forearms hurt. I attribute this to resisting the tendency of the paddle to flutter when used the wrong orientation. The crack has been repaired with two types of epoxy and is holding up to use. I'm going to carve another paddle to the same plans with a Sitka core for greater strength.
I am not a engineer or trained physicist and do not want to get into discussions about water flow around different shapes; I would be in over my head in such discussions. What I'm offering is my 9 year experience with the Skinboat School Aleutian and two years with the Beltraine Aleutian (he attributes his design to a paddle in the Smithsonian).