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PostPosted: Sun May 11, 2008 1:30 am 
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Site Rank - Deck Hand

Joined: Sat Apr 19, 2008 12:30 am
Posts: 13
Location: Belgium
I had not yet the chance to sail the AI in stronger winds but this looks very much like what happens to windsurfers (which I was during 26 years) and what is called a spin-out.
When the pressure on the rudder is too high (or on the "fin" in the case of a surfboard) cavitation (vacuum or air around the rudder) can suddenly remove all control. It happens when being over-powered causing too much pressure on the fin. A windsurfer can bring the center point of force forward by bringing the sail forward and by changing the position of his feet. This you cannot do with the AI of course. As mentioned quite often in this discussion furling is the solution because it brings the center point of the force forward. Ideally all side forces (drift) should be handled by the dagger board.

gilbert


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PostPosted: Tue May 13, 2008 9:03 am 
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Site Rank - Deck Hand

Joined: Tue Feb 20, 2007 1:27 pm
Posts: 7
Location: Wichita, KS
I've only been AI sailing about a year and a half, but have sailed small to large craft for decades. Most sailboats are designed with a "weather helm" built in so that in case of high gusts or loss of control, the sailboat will head into the wind and luff on it's own. Sort of like having a jet ski stall or go in circles when the rider falls off.

That behavior is designed in by the relative installation locations of the mast, rudder, keel, etc.. Basically center of effort a tad aft to center of resistance. Moving the rudder forward a bit should reduce weather helm to my thoughts, but that effect is mainly due to the mast/keel relationship.

Keep on posting, I am learning a great deal!

John


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 Post subject: can't tack to the port
PostPosted: Thu Aug 14, 2008 4:36 pm 
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Site Rank - Deck Hand

Joined: Thu Jul 31, 2008 12:03 pm
Posts: 1
I have the 07 AI and I notice that the rudder turns sharper for the starboard tack then the port tack and that if the wind is strong enough, it will weather helm on a port tack - this does not happen on the starboard tack??? I have the new rudder blade... Any ideas


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 Post subject:
PostPosted: Thu Aug 14, 2008 7:09 pm 
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Hobie Approved Guru

Joined: Sat Nov 12, 2005 10:46 pm
Posts: 2380
Location: Escondido
Remove any slack in your rudder directional lines. This gives you better response and more throw.

With maximum tiller deflection in either direction, check the corresponding rudder angle and adjust as necessary to equalize. 8)


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PostPosted: Fri Aug 15, 2008 12:41 am 
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Joined: Thu May 25, 2006 5:17 pm
Posts: 203
Location: Ettalong Beach, Central Coast, Australia
rdethman wrote:
I have the 07 AI and I notice that the rudder turns sharper for the starboard tack then the port tack and that if the wind is strong enough, it will weather helm on a port tack - this does not happen on the starboard tack??? I have the new rudder blade... Any ideas


Pretty much exactly the issue I had when I started this thread.

Turn the rudder full over, and discover whether you can HEAR the water. If you can't probably you don't have enough rudder deflection.

My suggestion is to turn the rudder the full amount you want, which is just off the plastic hull and take up the slack, repeat other side. This I found way better than trying to adjust for the center position.


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