Hull shape effect on roll

This may sound like a stupid question; but, does rocker in a hull effect rolling effort. I have been asked by many people what boat in my fleet is easiest to roll, so I compared them all, one after another and I cannot really tell any major noticeable difference.

Every boat does take a different set up to get “locked in” for an effective hip roll up, but the effort remains about the same.

I have a wide range of boats: Necky Manatou, WS Zephyr, Valley Avocet, Pyrahna Speeder and LL Stinger. All about the same effort.

Try to do a static brace …
Try to do a static brace and a slow-ish no-effort hand-roll in each, and let us know what you think. I suspect the Zephyr might come on top as the easiest -:slight_smile:

Rocker?
Rocker is a front to back dimension, it may reduce waterline length but that might not be the factor most would notice.



The cross section of the hull - width, height roundness etc - around the cockpit might have a greater effect on how a roll feels.

Hot Dog vs Hamburger
I know this doesn’t answer your question but it might help beginners who happen to read this… When I went to roll classes you weren’t allowed to bring your own boat. The sponsors brought little kayaks that didn’t take up much room. Most of them were shaped like hamburgers but two or three were shaped like hot dogs. It didn’t take long before the students were scrambling to get in the hot dog boats. They rolled much easier for beginners. Pirouette was the model name, I think.

hull shape but not rocker so much
I think hull shape and width play a big roll on how a kayak rolls. not so much rocker.



I cant believe you cant tell the difference in those boats listed. You must have an explosive type white water roll. My Valley Avocet RM clearly rolls way way easier than many other kayaks I have tried. I have tried lets just say a lot of different boats as I always like going to demo days all around me and roll every boat I try.



Here’s me doing shotgun roll in Avocet

http://www.youtube.com/watch?v=c7ps8FfeVQ4

The
Rocker doesn’t make the kayak roll easier…BUT…if you sit up too early an a rear deck finishing roll…less rocker will dampen some of the turning that the kayak will do as the blade changes from a planning relation with the surface of the water to a sweeping motion with the water. {this is one clue that you are sitting up too soon.}



Best Wishes

Roy

So
in a sense…it {no rocker or at least very little rocker} helps you to stick the roll and if your form is slightly off for the moment…it hides the slight oops moment



Best Wishes

Roy

Pirouette VERY easy

– Last Updated: Dec-27-15 12:25 PM EST –

I have a quite old similarly easy boat under the back deck, it hasn't cracked yet so it is good for boggy creek crawls. Piedra, but between that and the Pirouette it is hard to say which is easier.

I wish to heck they had put me in one of them early on rather than the various other boats... it remains the only boat that, when I have a decent roll in the tank to start with, I can count on hand rolling on the right. But in some respects it is too easy. When I am working on recovering my roll like this winter I have to leave it home. It lets me get away with mistakes that'll kill a roll in my go-to sea kayak.

Very fun old boat though.

yea, that is not me
I am probably 90% successful in either direction, but no where near that elegant, more like a jack in the box blowing to the surface.

I have arthritis in my back, and ahead the size of a pumpkin, so explosive probably is the nice way to describe my roll. Until I learned a good hip snap and follow up catch, it was really ugly.

And the reason is…
Volume distribution and hull shape. Too much and too little volume in certain areas, and your kayak will be harder to roll. Above water volume and shape (deck shape, as opposed to hull shape) as well as cockpit dimensions and shape also make a big difference.



You will feel the difference between kayaks when you try a type of roll that does not require much effort, or that you can barely make work, so even minor differences in boats will show themselves. When I was learning hand-rolling, I could do it in two of my kayaks (Dagger Axiom 8.5 and WS Zephyr 15.5) and I could not do it in P&H Delphin (I could roll all three easily with the paddle). The former would just sink and get “under” me, the latter had more volume around the middle that kept me higher above the water, more square shaped hull that required a bit more initial nudge to flip over, and higher rear deck that was in the way of a flat layback.



By practicing a static brace you can experience how cockpit shape helps or hinders your rolling, also you can feel if the kayak is helping, not helping, or fighting you - some boats are just better at rolling than others…