Sea Kayak Paddle Shaft Diameter
Size does matter - and it may affect your blade control.
By Nigel Foster
First appeared in Canoe and Kayak July 2006 issue
You’ll hear people say that thin paddle shafts are for small hands and fat paddle shafts are for big hands. That’s a huge oversimplification of what happens when we paddle. The difference between a “thin” shaft and a “fat” shaft is seldom more than 1/8 inch in diameter. That’s little more than 1/2 inch difference in circumference between a shaft for a child and a shaft for a giant!
What happens when you reduce the diameter too much? A thin shaft cuts more into your hand with each stroke, potentially causing bruises. Your fingernails may also dig into the heel of your hand.
What happens when you increase the shaft diameter too much? Your hand grasps the shaft openly, so your fingers cannot reach your thumb. The bigger shaft tends to be heavier because of the extra material needed.
Control of your blade at different angles in the water is dependent on your grip, but indexing, or shaping, the shaft helps a lot. Some manufacturers index by fixing a shaped heel to the shaft in the grip area, then “shrink-wrapping” for a smooth feel. This offers the maximum indexing effect. Others index by distorting the shaft from round to oval in the grip area. It is not essential to have indexing for both hands. It is sufficient to index only for your control hand, and in fact, bulky indexing can be awkward in your noncontrol hand unless you only use your paddle unfeathered.
Indexing also allows you to feel the blade angle from the shaft. With your eyes shut, you can pick up and align your blade accurately by feel alone, something you cannot do without indexing.
Let’s look at your control of the blade angle. Hold your paddle upright beside the kayak as for a draw stroke. With a thin shaft, each small movement you make with your hand causes a big change of angle in the blade. With a fat shaft, a small movement of your hand leads to a small change of angle. So a broader shaft offers more precision when you try to make fine adjustments to the blade angle. You have better control. Does this control depend on the size of your hand? No. You can have good blade control with big or little hands, but you get better blade control with fatter shafts than with thin ones. Choose a thin shaft if you feel more comfortable with it, but select the biggest you can so you have the option of that fine blade control. Indexing will optimize your control with any shaft diameter.
Next let’s look at blades. Blades vary from around 4 to 8 inches wide. If you glide forward in your kayak with your blade upright in the water beside you in a neutral position (edge first so the water flows along both faces from edge to edge with almost no resistance), and then increase the blade angle, you feel torque, or “twist,” in the shaft. You can oppose this torque by gripping the shaft, but a broad blade creates more torque than a narrow one. In other words, a broad blade is more sensitive to small changes of angle than a narrow one. You need a more controlled hand to perform a bow rudder with an upright blade if your blade is broad. More control requires a fatter shaft. With a narrower blade there is less torque on the shaft, so a thinner shaft is not such a disadvantage.
We more often use strokes requiring control of the blade angle and an upright blade when we use a shorter rather than longer paddle. These are techniques associated more with an upright paddling style than a low paddling style. So while I believe that a fatter shaft always offers more control than a thinner one, and that indexing is an advantage, the difference is most noticeable when you use an upright paddling style, which generally favors a shorter paddle and a broader blade.
NIGEL FOSTER began paddling in a canvas kayak and has since designed several kayaks of his own. He has crossed the English Channel several time, circumnaviogated Iceland by kayak, and undertaken many expeditions to remote seas. He’s a noted instructor as well and a partner in Sweetwaer kayaks in Florida.