In the previous installation of this multi-post series on kayak rolling I have discussed how the invisible lower body hides the key to a successful kayak roll and how you can't learn it just by watching. In the upcoming posts I will analyze the critical components of the roll as well as commonly cited mistakes in rolling. This post is about the hip snap.
The ultimate purpose of the kayak roll maneuver is to restore the weight of the upper body on top of the kayak. When the weight of the body is on top of the center of buoyancy we have a stable boat. When it is not, a paddler either braces or capsizes. The latter is a precursor to a kayak roll and when it happens the body is, at best, on the same plane as center of buoyancy and usually under it. If you want to smile and breathe again only one arrangement will work: body on top, kayak underneath.
After you set up for the roll, the first element in the sequence is the hip snap. Good instructor will tell you to rotate the boat right side up applying as little pressure on the blade as possible. Well, at least that is what I used to tell the students. My mission for these posts is a clear mental picture of what you should be doing to get a bombproof roll. To that end, we need to understand how the hip snap helps you toward the ultimate goal of the kayak roll. Is the real purpose of the hip snap to rotate the boat right side up?
Do this now in your head or at your next pool session or the next time you paddle in the lake. Lay down on the surface of the water, let the boat capsize on top of you and hold on to the side of pool or to a partner's boat. As illustrated in panel A of the figure, this is a regular set-up for practicing the hip snap.
Now execute the hip snap—rotate the boat from upside down to right side up with your thighs and hips. If you keep the boat at a constant distance from your head throughout, you will end up in a position depicted in panel B. I think this captures the essence of the hip snap. Please comment if you have other ideas.
Does this hip snap bring you any closer to the ultimate goal of the kayak roll? Does flipping the boat from upside down to right side up restore the body on top of the boat? No, it does not. The buoyancy of the boat (green arrow) and the weight of the body (red arrow) have not converged. The re-alignment will come next. Getting the body weight over the kayak is not a part of the hip snap. Nor is the complete righting of the boat needed.
This mental exercise should illustrate the fact that the hip snap by itself, the rotation of the boat, does not do much for the restoration of the balance that was disrupted by the capsize. For that to happen, the red arrow needs to end up on top of the green arrow—body over boat. The flipping of the boat is a means to something else.
In your mind, move green and red arrows toward each other in panel A. Then repeat it in panel B. The difference the hip snap had made should be obvious immediately. Before the hip snap you would have been aligning the body UNDER the center of buoyancy! What the hip snap accomplished was to get the boat out of the way of repositioning your body on top of the boat.
A really powerful hip snap can do something else for you. It can initiate the rotational momentum which will wind the body onto the boat like string on a spool. Doing so can contribute quite substantially to the eventual restoration of balance. However, the powerful hip snap is not necessary for the successful roll. I would go further than that, power hip snap is not the optimal way to mobilize available energies toward your goal and it puts unnecessary stress on your body in the process.
This is the scoop on hip sanp: it is the first step in a successful roll and its goal is to remove the boat out of the way of body-over-boat alignment. I will discuss the three most common mistakes in executing a kayak roll—the diving blade, the rising head, and the punching hand—and how they fit in the mental picture of the bombproof roll in the future posts. In the meantime, please comment with your observations.