Double paddle length?

[BrianY]

How do you determine the proper length of a double paddle for use with a kayak or Rob Roy type canoe? I imagine that it depends on the height of the user and the beam of the boat, right? Also, are there any guidelines for the blade area? I'm about to start building a double paddle canoe with my 8 year old son for his use and it would be nice to have a proper paddle to go with it.

[Ian McColgin]

For cruising use and especially in plumper boats, it's nice to have the paddle about as long as the height the paddler can reach.

Blades need more width in heavier boats, like the Rob Roy, but many of the commercial paddles have too much blade.

I don't see much merit, for cruising, in spooned or asymetrical blades. A nice shape with the raised shaft going most of the way down on both sides is very effective for all strokes and you need not then fuss with power side issues.

Finally, it turns out that blades at an honest 90 degrees not only feather best but that makes for a very natural hand position if you're paddling correctly.

G'luck

[P.I. Stazzer-Newt]

Ian has it about right, the old rule was that the paddler should be able to curl the top two joints of his fingers over the tip of the paddle.
Feather angles are a matter of huge debate but symetrical 90° is as good a starting place as any.

The single thing that makes the biggest difference to me is the Loom section, for the blades described, I like an oval about 33mm by 28mm but your kid will have his own preference - sandpaper and time will sort the shape and then he can learn to varnish.

[Todd Bradshaw]

I'd be torn between a Greenland paddle (very fast learning curve due to no feather and excellent performance once you get used to it) and something similar to Derek Hutchinson's Toksook paddle if you want one that's feathered.
http://www.useakayak.org/toksook.html

Ninety degree feathers would be my choice as well (my non-90 degree paddles drive me nuts in a wind because the wind wants to twist them). I like very oval shafts down in the grip areas so that you know what direction the blades are pointing just by feel. Double paddle canoe paddles tend to get banged on the gunwale fairly frequently, so I would use something that resists dings (like ash) for the shaft. A cedar or spruce shaft would certainly make a lighter paddle, but they're likely to get pretty beat up in time. I'd probably start about fingertip length since you have taller sides to reach over that you would in a kayak. You might eventually find that one even longer worked better, but time will tell.

[Thorne]

The narrow Greenland paddle is certainly coming back into popularity -- worth considering as per the very knowledgeable posts above.

From - http://members.aol.com/kayakillen/katabasis/Greenland.htm
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THE PADDLE
The Inuit paddles used were narrow bladed being between 6 feet long for a Storm paddle up to 8 feet for the normal paddle. They usually were 3 ½" to 4" wide at the tip tapering down toward the oval loom. Some, such as the Newcastle were willow leaf shaped. Many were edged and tipped with bone or ivory.
Narrow bladed paddles for ocean application have been used for centuries under the severest of conditions. Two great sea kayaking cultures, the Aleuts and the Greenlanders have developed remarkably similar paddles though separated by great distances. If they are so good how did the wide blade ‘Euro’ paddle used today by most paddlers come into use? Simple. It started in river kayaking which evolved from river canoeing. Early paddlers were using open canoes, eventually decking some of them and then developing river kayaks. With the reemergence of the seakayak, it was natural to carry the use of the wide blade, feathered paddle over to the sea since everyone was already utilizing it. Thus, the Euro paddle became the standard for those who followed into the sport.
This type of paddle is very appropriate for river paddling and also has been used in many major expeditions and crossings. There is no doubt that it works but we just can’t dismiss the virtues of the Greenland style paddle without giving it a fair shake. They are well suited for touring and long distance paddling, not to mention sculls, braces and rolls
Kayakers are strongly divided over the paddle issue and I don’t want to fuel it anymore but it is important to note that almost all seakayakers who have switched over to a narrow blade have started out paddling with a wide bladed paddle, myself included. The reverse is not true. As John Heath, a long time student of traditional kayaks and techniques has said, "Quite simply, to attempt certain rolling and rescue techniques with a feathered, wide-bladed paddle is like trying to thread a needle while wearing boxing gloves-with one glove on backwards."

WHY IT WORKS!
For a given area and all other factors being equal, a flat shape with the highest coefficient of drag gives the best grip on the water. When various flat surfaces of equal area are pulled through the water, a round shape gives the least drag and a long rectangular shape, such as a Greenland style, gives the highest drag or best ‘bite (which is what is desired)’. A wide blade paddle falls somewhere in between these shapes. When a paddle is pulled through the water, the water on the working blade moves outward to the edges of the paddle and curls around forming an eddy or vortex on the back side These are shed alternately and is the reason for the zigzag motion felt at certain speeds. It is these eddies that create the ‘push’ on the paddle. Only with a narrow paddle is this vortex shedding noticeable because the vortex is large in relation to the blade.
The opposite is true for the non working blade. In hydrodynamics, the rectangular shape has the highest coefficient of drag but aerodynamically it has one of the lowest. This coupled with the lower Greenland stroke makes the effect of wind on the blade minimal. With feathered paddles, as the working blade is pulling through the water, the other is edge on to the wind. This may be a slight advantage for wide paddles when heading into the wind but what happens when paddling with a beam wind. A sudden, powerful gust may catch the unprepared paddler and capsize them. The working blade is edge on to the water and will offer no support to counteract the effect of the wind.
Where a wide bladed paddle is useful for quick, powerful strokes such as would be needed on the river or in racing, it can be very fatiguing for touring. Similar to a mountain bike in low gear for going through dirt and sand versus a touring bike in high gear. Initially, a narrow paddle will offer less power but after a kayak is at cruising speed it makes no difference.
Another consideration is that a narrow paddle gives less muscle shock since it develops resistance more slowly. Wooden paddles flex more, acting as shock absorbers in the beginning of the stroke and giving back the snap at the end.
It has been said that the Greenlanders did not have the technology to make wide bladed paddles or feather them. Nonsense. The paddle could have been made as a frame and covered with skin or thin pieces of wood or they could have built up the width the same way they attached the bone or ivory tips and edging to the narrow bladed paddles. As far as feathering goes, there is no secret to making a feathered Greenland paddle. I have made them quite easily and there are a few feathered Greenland paddles in the museums so the validity of that statement disintegrates . The paddle evolved as a narrow and unfeathered blade because, quite simply, it works.

[StevenBauer]

I've read that kids paddles don't need to be shorter than adult paddles as much as lighter. The gunwale height and geometry between the water and the paddler stay the same but the kids aren't as strong. A nice spruce greenland style paddle seems a good idea. You've got the current issue of WoodenBoat?

http://www.woodenboat.com/190002.jpg

Steven

[Todd Bradshaw]

I love Greenland paddles and haven't seriously used any of my euro-style paddles for about three years now. My concern above about flat-out recommending one in this case has to do with the gunwale height and the beam at which that higher gunwale sits on a double paddle canoe. The Greenland paddle works best paddled "Greenland style" (big surprise...) which is somewhat different from your average kayaking stroke. The angle of the shaft is noticably lower, the paddle is in close to your torso nearly all the time and you can do about 90% of your paddling with your elbows bent 90 degrees or more as you rotate your body to follow the blades as you paddle. When you switch to a more euro-style motion (steeper shaft angle, blade planted closer to the hull, more arm extension, upper arm nearly straight and straight out from your shoulder at the top of a stroke, etc.) with a Greenland paddle it starts to rapidly lose efficiency and often to also catch more wind. Unless the sides and gunwales on the canoe are either very low or very close to the paddler's hips, the proper low Greenland-style stroke may not be possible (at least not without beating the hell out of the gunwales and paddle shaft). If, as a result of beam and side height, you're forced to use a Greenland paddle more like a Euro-paddle, it may not be the best choice.

In any case, it only costs about six bucks to make one and see if it works (plus, if it doesn't you can always build a boat for it). If you need a quick pattern for one there is a PDF file with a measured drawing of the ones I build for my wife in my web-closet. She's about 5'7" tall, so you might need to adjust shaft and blade lengths a bit for someone shorter.

The file is here
http://webpages.charter.net/tbradshaw/!GREENLA.PDF