Luc
It is surprising how poor a single outrigger is. It costs about 10% in speed so contribution to drag is much higher than 10%.
Outrigger canoes get very favourable time allowance in the Murray Marathon. Both wind and water drag are much higher than a kayak. They are in the first starting group with the heavy touring kayaks.
My twin stabilisers add 4kg in a total of 90kg so extra drag from the load on the main hull is maybe 2%. They are set to ride one of the diagonal waves from the hull and do not touch the surface at rest. Tweaking them makes a noticeable difference.
The twin stabilisers offer a wide margin on stability. It means there is little energy cost in keeping the boat level. With racing kayaks and surfskis there is quite a high energy cost in keeping the boat upright. This really shows over a long distance. In this regard the last two 24 hour land distance records were set on trikes rather than two wheelers. (Current record a bit over 1200km).
The righting moment of a single outrigger is related to its initial load. This is adjustable by setting the initial list. With paddling the load can be made low because the paddle is used for ultimate stability. If you watch an OC1 on waves they will lift the outrigger when they get high speed on a wave and can use the rudder for stability. I have flipped the one I had with pedal drive just by turning too fast.
So a long answer to a simple question but it is something I have compared in detail.
Rick
On 24/05/2011, at 6:22 AM, LucD wrote:
Rick, I suppose that while "biking" a symmetric double outrigger setup is natural. Would you lose more using just a single one sided outrigger than you gain in weight saving? Is some proa thinking useful here? You could bias the balance while cruising to one side with an "escape" flick of the rudder in the off chance of heeling over to the other side?
The advantage of thought experiments is that one does not get wet ;-)
Thank you,
Luc
Rick Willoughby
03 9796 2415
0419 104 821
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