Bill Bremmer makes them square
Maybe he does it because it is easier or maybe that little bit of extra area helps. Anyway it has worked very well for me so far so I am less inclined to change it.
square is for
digging into the bottom when canoeing, round is for less drag when kayaking or racing, slaloms.
a round or ovalish shape spins off fewer eddy shapes as water leaves the surface and edge with fewer conflicts between eddies, less friction. Water leaves at different speeds.
With a flat edge, water tends leaving together, more friction.
one exit or many exits.
There are results searching: kayak paddle efficiency design in Google Images but so far not in Utube video.
Look in naval architecture and the navy’s test pool for results and the correct search terms.
I expect there are video’s of water leaving the edge.
Either works fine…
…but squared corners are more likely to chip or otherwise get damaged in use.
GP tip shape
I prefer GP tips to be round or even slightly pointed but I have used a number of “sweet” GPs with very different tip shapes.
FWIW, both round and square (and many other shapes) are traditional. In talking with Greenlanders, tip shape was highly evolved for hunting in different areas. Some hunters in quiet fiords prefer square tips, as the water reliably drips at the “corner” making “drip management” easier (it only takes a drip or two of water to scare an alert seal). That said, some hunters have written that in rougher conditions that round tips are quieter.
Personally, I’d just go with what you find most esthetically pleasing and makes less noise/ventilation in the conditions you normally paddle in.
IMO, more than tip shape is how thin the tips and blade edges are. Any blade that is left thick and clunky at the tip (as if you just lopped it off with a saw) will make noise and encourage ventilation, regardless of its shape.
Thank you. I have made GP for other
people and the question came up. I have made them both ways and the users have been happy with them.
At one or two a year, I am no threat to people who do it for a living.
Neither square or round…
I make mine "squarish..." : )
Just cause I prefer them that way....
it’s when that loom and shoulder feel perfect in the hands. Ahhhh. Thanks Bill.
round blade’s water
leaves edges at different times sez local noise.
For myself the shape of the tip is all
about paddle stroke efficiency. The faster I can get the blade planted and start applying power without ventilation is what I use. Many other greenland paddlers like other shapes of tips so I would recomend you try all shapes of tips and see what works best for your stroke. I like a tip that is rounded, just a little less than half a circle. I keep the thickness a full 1/2" thick that is rounded over. This is something you can keep playing with until you find what works for you. Enjoy.
Rounded is quieter for me
I have a hard time planting a square-tip paddle quietly. Maybe I’m not thinning them down to a sharp enough edge, but I get a better result with a somewhat rounded tip.
I make a part-rounded tip that looks good to me and works well. My complex template for making this shape is a coffee can lid. It has a dot in the center that I line up with the center line on the paddle and draw the curve. It just looks right to me.
For me it doesn’t amount to a
hill of beans. The big thing is the loom and shoulder area. Thanks Bill.