Not finding narrow blade (my preference) long double paddles. Canoe 27 lbs, 12' x 28" lap plywood. Single paddle best so far is fairly short bent. (considering small tapered blade, fairly short shaft single blade, thin hydrofoil for in-water paddling)

Length, blade shape/size, what am I forgetting? I can make a paddle without issue.

LENGTH: Tentative plan 102" (260 cm) Have been using Werner Skagit 90" 6"x18" blades and Greenland long x 3" blade, both 90". Both feel short at least 4" per side. Werner is a bit clunky and drips horribly. Longer shaft would increase clunk. Greenland feels better, flies more easily, but really feels short unless I swing arms out or use sliding stroke. Werner really gives power, and I can wing it hard if I want and get the boat scooting. Not really my goal.

Recommendations so far online (not specifically for narrow blades) indicate 260 cm (102") to 280 cm (110"). 260 is 6" longer per side, seems rather reasonable, and I can get 5/4" x 6" x 12 cedar, laminate to build up loom.

BLADE: Sizes for Euro kayak paddles seem around 5.5" to 6 " by 16 to 23. Area of 86 to 110 in2. Straight oars are about 5.5 x 23, 115 in2. I'd be getting 23 to 26 of paddle in the water, 25x4" = 100 in2, probably enough for parallel sided blades. Thinking more along lines of Fishell Ray Special shape (see 64RSCwebsite_053bb7a8-c1d1-4de8-9cb1-f12e1e81e2c0_540x.png (540×1006) (shopify.com) ) based upon great feel of Special on entry - although I'm using Special mostly always in water. Seems balanced with wider blade towards surface making up for lower density and speed through water.

So I'm thinking 5" tapering to 4", 25", square tip to begin with, on 52" shaft. That's 112- in2. Should be more than sufficient. Try that a bit, round or shape, reduce area, as seems necessary.

WHAT AM I FORGETTING?

I intend to make thin blades, relatively, my usual fairly thin edge hydrofoil. Any reason for using ridge or other shape, asymmetry fore and aft? Any reason for attempt to balance blade?

Other things I might be missing?

Thanks much for any thoughts on this.