Interesting discussion. I meant to post a note on this thread last week but got tied up with work. John Winter's posts have just reminded me what I was thinking. I'm not sure how much the inverted stability (or lack of it) is important to rollability. Someone pointed out that most non-rollers fail at the last hurdle - getting their body out of the water and over their boat. I don't think that the stability curve is necessarily an important factor in this, but rather the fact that weak rollers rely on momentum to help them up at the end .... and as Winters pointed out we need to consider roll damping. My observation rolling a variety of boats is that given roughly the same input they each have a speed which they roll at. white water boats / pool trainers come round really quickly and a roll like a c-c works effectively. I've seen people with what look like effective rolls in such boats surprised by sea kayaks though, which in general roll much more slowly (I presume after reading Winter's posts because of the roll damping effect of the boats shape). With the same input, by the time a rotobat would be up a sea kayak may be only one quarter the way around, and if the roller has run out of momentum, or been surprised at not being up and stalls the paddle, the roll fails. The rolling input therefore needs to be timed to the boat, and a quick explosive input can be less effective than prolonged support from a slow screw roll or sculling rolls. On a similar note my observation of rolling fully loaded boats is that the laden boat with its increased inertia is further slowed down when rolling. Ditto deck gear, spare paddles and deck bags etc. If you rely on just setting up then going through the motions to roll without being aware of what the boat is doing then different levels of roll damping will feel like they make a roll harder - but the boat may be just as 'easy' to roll, you just need to match your input to the boats speed of rotation. My point is I guess that like much about boat handling its hard to isolate familiarity with a boats characteristics to the performance effect of the boats shape. The new generation of extreme play boats like 'Mr Clean' introduce another dimension ... with such little volume in the ends of very short boats the fore/aft pitch stability, or lack of it, adds another level of complexity. Apply paddle support for a roll at anything other than 90 degrees to the boat and it either spins or stands on its tail .... Cheers Colin Calder 57º19'N 2º10'W *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Mon Jul 03 2000 - 01:59:27 PDT
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