 A new keel design revealed.
Člie Canivenc has a new idea under construction.
Enjoy, it is available for other home builders too.
Or you can order a complete boat by Elie.
And he does parts like rudders etc.
Good to see a new construction being realized. This is what minis make special... www.elie-canivenc.com He promised to keep us updated in this for me exciting new function... His article:
Intro :
« When I finished the 1999 Mini-Transat Race on my old Berret proto, I promised myself to come back on a more competitive proto and give my best in my knowledge of design, building process, and sailing …
The large innovations about the variable geometry keel is a good opportunity to concrete my project.
So now, It's time to start !
Knowing it's as difficult to find 50.000€ to race the mini as 1.000.000€ to race the
Vendee; I begin the building of the hull and deck with my own money and will look for some sponsorship later ... when the boat will be decked".
The main innovation of that keel is to be moved in its lateral axis about 730 mm on each side. In fact the keel axis is fixed on two rails and can be moved from side to side by a simple tackle system. By this way, respecting the 10° rule, you get a very powerful boat when the heel increase.At 20° hell angle, the gain is easy to calculate:
The transversal difference between a classic canting keel and mine is 109 mm, the bulb weight is 360 kg so the righting moment gain is 0.109*360*1.891=74 kg.m (equivalent of a guy sitting on the rail). In comparison, a crew member of 75 kg sited out create a righting moment gain of 75*1.087=81.52 kg.m
At 30°, the gain of the keel become 0.178*360*2211=141.7 kg.m
At this angle, the righting moment of a crew member of 75 kgs sitting on the rail is 0.939*75=70.42 kg.m
So the gain of the licensed keel at 30° of heel equals the righting moment of two crew member on the rail.... on a mini-Transat proto, it's a large gain !
The hydrodynamics calculations allows to quantify the gain at 15% of speed increase from upwind to abeam conditions.
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In upwind conditions, you are looking to cant the keel and move the weight forward to enhance pointing in strong waves and reduce the pitching. In contrast to the inertia water ballast, I have a got a system to move the weight forward. The rail system of
the transversal keel system is curved and allows to move the bulb forward when you move the keel ! By this way , the gravity center of the bulb is moved forward.
When the keel is canted and moved up, due to the curve of the rail, the fin keel is rotated about 5° and then is aligned with the angle of attack since the leeway angle of the hull is around 5°. Then the drag of the fin is greatly reduced and the lift capacity of the profile is optimized. Elie Canivenc In all this looks like a great concept, looks not to complicated, and has a gain. The 15% is a bit much though would be happy with 5% more performance...
So it is not a cantingkeel, but a transverse sliding keel. It is going to be interesting to
test this puppy. To close the gap in the hull a simple fiberglass plate can do, but with the curved hull that will be difficult. The curved rail is a very nice trick...
And if i am not wrong, you can have the keel in a lifting profile, like a normal keel, while Elie sailed on minis and Open 60's, so he has first hand experience of the systems used...
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