“Clothes and manners do not make the man; but, when he is made, they greatly improve his appearance.” – Henry Ward Beecher.
 
It is possible that the kayak can make the roller, or at least greatly improve her or his rolling?
 
For me, this has been a three kayak building year. First the Qajaqpak, then the Shrike Too, and now the Shrike-R. The purpose of the Shrike-R build was to create a kayak that would replace the aging Tahe Greenland as my rolling kayak. Being the proud owner of over a dozen kayaks I have, through practical trial and error, been able to establish some of the characteristics that make it easier or harder for me to roll a kayak. The Shrike-R provided me a platform to experiment with several parameters to see if I could develop a kayak that would allow me to complete some of the harder rolls with greater ease, and end up with a sharable design for others who seek a simple to build great rolling kayak, whilst retaining the elegance of the original West Greenland kayaks that inspired the Shrike project.
 
shrike-r2

Designing for Roll-ability

I focused on three aspects of the kayak design to improve roll-ability:
Low freeboard – It should come as no surprise that low freeboard makes a layback recovery easier. There is less height to lift ones upper body to get it onto the deck. What is less obvious is the effect that low free board has on how the kayak will help or hinder a static brace. A kayak with low freeboard ends up being thinner like a surf board. Put this thin design on edge and it will naturally sink lower in the water than a similarly loaded higher freeboard kayak. The low freeboard allows the roller to “sink” the gunwale deeper during the roll which lowers the center of gravity of the lower half of the body, the part of the body that is inside the kayak, under the deck. By lowering the center of gravity, the force provided by the paddler’s body’s buoyancy or sculling paddle action has a proportionally greater righting or balancing effect. This thinner shape and deeper position in the water creates another interesting effect, the center of buoyancy is at a greater distance from the center of rotation during the roll. The buoyancy of the kayak helps complete the last phase of the roll for you in a greater way than a thicker (think rounder) kayak hull. There is a downside to this affect. A flatter thinner kayak actually likes to stay upside down more than a thicker rounder kayak. Which brings me to the next design area.
Low curved foredeck – The foredeck has several important impacts on the roll-ability of a kayak. The cross section shape can affect the resistance to rotation. Overly flat decks result in the kayak sticking upside down. The transition from deck, through the gunwale, to the top-sides can create considerable drag. The height of the deck affects the comfort of the sitting and paddling posture. Too low a deck and the legs are forced straight, which for some people can be a very uncomfortable position. Too high a deck and it becomes very hard to maintain firm contact between the roller’s thighs and the kayak. Another affect the deck height has is the angle of the thighs and pelvis. By being able to lift the knees slightly the pelvis opens which then allows the paddler’s chest to get lower on the foredeck either during the start of rolls or recoveries of forward finishing rolls.
Wide cockpit – Examination of surveys of Greenland kayaks reveals nearly round shaped cockpits that extend out across the entire width of the kayak. This is especially true for those Inuit who rolled their kayaks, it is less true for those that used their kayaks to haul loads over great distances where seaworthiness was more important. By extending the cockpit as wide as practical the roller’s body tends to fall down to the edge of the kayak during the roll, especially during the last third of the rotation. Getting the body to the edge lowers the center of gravity, the extra width also increases the tangent from the center of the kayak to the rim of the cockpit which lowers the angle that the spine makes, enabling a lower recovery.
 
shrike-r3

Build modifications

The Shrike-R design took these three parameters and attempted to maximize their affect. Practically I took the Shrike standard templates and lowered the gunwale by 60mm along the entire length of the kayak. This resulted in roughly 20mm (0.75 inches) of freeboard when paddling in shorts and a tuilik. For context, unclothed I weigh 84kg (185lbs). The foredeck height was set using the same masik as the Shrike-Too template, it was reduced in width by about 20mm due to the reduction caused by the lower deck as the topsides taper in towards the chines. The cockpit was broadened to the maximum, the distance between the inner faces of the sheer clamps (I used 15mm square section sheer clamps), I reduced the length of the cockpit by about 60mm (roughly 2”). I reduced the cockpit length to keep the circumference basically the same as the narrower and longer Shrike Too cockpit to allow my tuilik and spray skirts to be interchangeable. In order to aid entry and exit I reduced the height of the cockpit rim to just allow 10mm between the rim and the deck, this was the minimum I could get the neoprene tuilik and shock cord to fit under.
 
shrike-r

Sea Trials

When learning how a new kayak performs I general will lie back and slide into a sculling brace. You learn a lot about a kayak when in this position, and the sculling action give you the security of an easy recovery if you need it. When I slid into the water in the Shrike-R I was instantly at ease, I knew in that moment I had a winner. I simply let go of the paddle and hung there relishing the ease with which the kayak sat on its edge and supported me. Rolling was automatic, there were two distinct phases of rotation, the first and last 180 degrees. The first half of the roll was fluid and quiet, with limited disturbance to the water. During the last half of the rolls the kayak seemed to want to rush you to the surface, easily finishing the rolls for you. Like many hard chine designs, the roll finishes once you pass the point at which the secondary stability kicks in, so you finish with the kayak at a slight angle, a position where it is very stable. On my first outing I was able to perform numerous layback and forward finishing rolls with ease.
In the second outing I pushed myself harder to see where the limits of the kayak and my current level of fitness were. I have stronger recoveries on my dominant right side so a good test is to try my weaker side. First with a paddle, then a norsaq and finally with just my hand, the rolls came thick and fast. My final Pièce de résistance was to hand roll into a static brace, collapse the kayak onto me then hand roll up into another static brace on the opposite side and then finally recover.
I am extremely satisfied with this design and intend to spend the summer using it to improve upon my harder rolls and sculls.
If you are interested in learning more, and potentially building your own, you can download for free, or purchase paper copies of the plans for this design, and our three other versions, from the web site cnckayaks.com

Pursuing the perfect Greenland paddle
Qajaq Camp 2014

Comments

Pin It on Pinterest

Share This