How to buy a paddle

How to buy a paddle: the fluid dynamics

By John Winters

A cas ual a nd unsc ientific study of canoe boutiques leads me to believe that most paddlers buy their paddles based upon price, appearance, and someone’s recommendation. Sometimes these are good reasons. If all you have is $25, the merits of a $100 paddle are academic. But suppose you want the paddle that best suits your needs?

Paddle buyers should consider six important details. (I list them in no particular order of importance.)

__ Durability __ Weight __ Shaft size, length and grip __ Blade size __ Feel __ Efficiency

Dur abilit y

You probably won’t break a paddle just messing around the cottage lake, but the demands of wilderness tripping can reduce a perfectly lovely paddle to a piece of expensive kindling very quickly. Aluminum shafted thermoplastic blades probably offer the ultimate in abuse-resistant paddles. Reinforced tips and clever laminating have made the word “lightweight” almost synonymous with durability.

Why not consider two paddles – one for regular use and a heavy spare for challenging conditions? Somehow that thought seems defeatist to me, so I take two lightweight paddles. My wiser friends tell me I will regret it some day but I tend towards studied laziness.

Weight

In this age of miracle adhesives and materials, no one should suffer with a heavy (more than 24 ounces) paddle. You’re going to lift that paddle a lot during a long trip, so it makes sense to lift as little as possible. But, will a light paddle be strong enough? The qualified answer is, “Yes,” if properly made. My own 18-ounce paddle has survived a cavalier attitude to paddle care and feeding; it’s also survived my love of shallow whitewater creeks. Yes, it has been cracked and dinged and repaired, but it always gets me home.

Unfortunately, there’s no way to look at $250 worth of carbon fibre and know if it was well made or not, so you must rely on the manufacturer’s reputation. You can, on the other hand, do some evaluation of wood paddles by eye. (Wooden paddles have come a long way in recent years.) The grain should be straight. The shaft should be laminated with the outside layers made from the hardest and strongest woods – usually ash, which is hard enough to withstand gunwale rubbing. Lighter woods work for blades, but need some form of impact resistant material on the edges, such as cast urethane, fiberglass or hardwood. Of course, the paddle should be no larger than necessary since size is weight.

Sh aft Si ze, Length and Grip

The diameter of the shaft depends upon the size of your hands. If the shaft is too small, you must grip the paddle more tightly; this constricts the blood vessels in your hand, and promotes fatigue.

So, how big should a paddle shaft be?

Let your arm fall naturally to your

side and let your hand assume its away from the shoulder (like a boxer One paddle grip doesn’t fit all peonatural attitude. Note that it curls making a jab), while the lower arm ple. The size you want is governed by into a state called “natural repose.” pulls at about belt level with the body the same considerations as the shaft The shaft should fit your hand in this in a comfortable posture. Obviously (i.e. the size of your hand in natural state. Probably. Most solid hardwood this means that what really matters repose). The shape of the grip is up paddles have relatively thin shafts is the height of your shoulder above to you. Some paddles have unidirecin order to keep the weight down the water, and that varies with tional grips (distinct front and back) and to achieve some kind of mystical seat height, or if you kneel. So the that allow fingers to curl neatly over flexibility. The same advice applies best way to know how long the padthe top. Not everyone likes them, but to aluminum paddles made from dle shaft should be is to get in the they can be made to fit your hand off-the-shelf extrusions, chosen for canoe and sit down. quite nicely with a little sculpting economies of production. Don’t worry Clearly you need a different paddle and sanding. too much about the shape of the shaft. for every boat you own. (Can you Hardwoods make the best grips U.S. government researchers studied hear the paddle-makers applauding?) because they do not get rough with this many years ago and discovered no Well, not necessarily. (The applause abuse. Teak (if you can find it) is the significant comfort advantage in oval, stops.) An extra five centimeters or so very best grip material. It has natural versus round, although an oval shaft will not hurt much. Five centimeters oils, requires no finishing beyond a provides more strength and stiffness. too small on the other hand will cause fine sanding, is not slippery, and has a increased fatigue. Marathon, freestyle, silky feel that improves with age. Length and whitewater play boaters who If you find the right grip and shaft

First let’s clear the air about a have highly specialized needs can size, then all you need is a good paddle’s length. The height of your just ignore all this. You need blade. nose, shoulder, navel, or any other absolute precision. part of your body means nothing when Note that all this advice applies only Paddle Blades choosing a paddle. What counts is to the shaft, not the total length of the There’s not enough room here to the location of the paddle blade when paddle. Unfortunately paddle lengths discuss the hydrodynamics of padyour arms and body are operating at supplied by manufacturers usually dle blades so here’s the short and their greatest efficiency. This means include the blade. TH_OttawaOutdoor.qxd 4/9/03 11:27 AM Page 1 sweet story. Blade efficiency depends that the upper arm is pushing straight Grips upon shape and size. Blade shape $ BESTGEAR ’ 03 BESTBUYS 1399. 00 CURRENT DESIGNS SQUAMISH w w w . t r a i l h e a d . c a SIERRA DESIGNS GAMMA AST $ 274 . 99 $ 249 . 99 ASOLO 520

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determines the coefficient of drag and lift produced by the paddle. There’s no need to understand what this means except to know that the more efficient blades get the same job done with a smaller area. Smaller size means lighter weight, which translates into even more paddling efficiency. Hydrodynamicists love this kind of thing, but who else cares?

What you want to know is whether the blade is right for you, and that is determined by how you paddle. If you naturally paddle at a high stroke rate— say 50 to 60 strokes per minute—you will want a smaller blade in the order of 140 square inches. If you paddle slowly or do a lot of braces, 160 square inches or so will work better.

Why the difference? Because the force exerted by the paddle is a function of its area and the paddle’s velocity.

Velocity?

Contrary to what many canoe instructors believe, your paddle moves through the water with each stroke. (It is not anchored in the water by some mystical force.) It doesn’t move far, but it doesn’t have to travel a great distance if the velocity is right. In fact, the force exerted increases by the square of velocity, so doubling the velocity results in four times as much thrust. Doubling the area only doubles the thrust (if the velocity remains constant), so fast strokers can get as much power with a small paddle as slow strokers get out of a large one.

A fast stroker using a large paddle will soon grow tired just as a slow stroker will soon resent a too-small paddle. So, consider carefully the blade area. Unfortunately paddle makers don’t often publish the area figures. They give blade length and width, but two paddles with the same dimensions can vary significantly in area. Since the size of the blade is so intimately tied to how you paddle, your best course is to try a large number of blades until you find the one you like best.

Paddle “Feel ”

No one can tell you how a paddle should “feel” because no one paddles in exactly the same way, at the same tempo or has the same physical characteristics as you do. So you can only tell how a paddle feels by comparing it with other paddles. If it feels good, it will stand out. Once you find a paddle you like, you will have to turn your thoughts to more practical issues, like efficiency.

Efficie ncy

Efficiency is the difference between how much power you put into the job versus how much you get out. If we were all built the same we could just design the most efficient paddle and leave it at that. But we must also consider our biomechanics, and fit the paddle to our bodies. Reducing the total lost energy is the goal and, since we’re all built differently and function best at different speeds, we have to match the paddle to our natural motion. This means nothing more than fitting the size to your paddling style, but always using the smallest blade possible.

What about blades with near-identical area? Research shows that wide, short blades are more efficient than narrow, long blades, and that spooned and cupped blades are more efficient than straight ones. As well, blades with less camber (less curvature of the face of the blade) are more efficient than more cambered blades. Also, research has shown that the profile (e.g. beavertail) doesn’t make a lot of difference, but a paddle’s tip and edges should be as sharp as is practical.

Now don’t rush out and buy a short, wide, spooned, flat faced, sharp-edged paddle. You may have specific needs that mandate something very different. I use eight very different paddles. Each does something exceptionally well, or fits a particular boat best. (Can you hear the paddle-makers cheering again?) You may not need that many paddles, but it has often been said that you cannot be too thin, too rich, or have too many canoes. (Legendary canoeist, Bill Mason, had 17 different canoes.) To that you might add that you can never have too many paddles.

See you on the water.

— John Winters is a well-know canoe designer living in Ontario.