Subject: Re: [harryproa] BD sailing
From: Arto Hakkarainen
Date: 10/12/2009, 10:23 AM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

 

The more I think about proa rudder issues the more I like the twin foil steering concept by Fulgencio that has been presented in proafiles: http://groups.yahoo.com/group/proa_file/files/Twin foil steering/
 
Downside of the concept is that it is not enough to have that system alone. It would need a rudder for downwind sailing and motoring, which means there must be additional foils. Of course the twin foils system with two rudders would provide all the steering you need. Adds complexity and weight though.
 
Many of the problems in harryproa concept seems to be related to the placement of rudders. Placing rudders in the hulls should make them more effective and also have the force vectors more balanced than placing them between the hulls.
 
Arto

--- On Thu, 10/8/09, Rudolf vd Brug <rpvdb@freeler.nl> wrote:

From: Rudolf vd Brug <rpvdb@freeler.nl>
Subject: [harryproa] BD sailing
To: harryproa@yahoogroups.com.au
Date: Thursday, October 8, 2009, 10:14 AM

 
Hi,
 
Yesterday we have been out sailing BD with the new rudder set up.
Wind about 16 knts.  After hoisting the sails we pulled the sheet and the boat luffed.
Pulled the other sheet to get the right bow pointing downwind and sheeted in again, the boat luffed.
After a few attempts I descided to take the jib down, and we got her going.
Rudder angle was about 10 deg. so no high speeds.We tried shunting and we had to get BD going really downwind to be able to build up enough speed to keep her from luffing straight into the wind.
After some time we set the jib while sailing on a close reach. Once the jib started pulling the boat luffed into the wind the rudder only putting the brakes on.
We took the jib down and proceeded without it. The front rudder has to be pulled up at least half way to keep the rudder angle 'down' to the 10 degres I mentioned. Front rudder all the way down makes it hard to keep the boat from luffing into the wind.
We also tried the front rudder tilted out of the water entirely which made made for very nervous steering behaviour.
Returning to the marina we were very disapointed.
 
As we brought BD to the marina after the launch we had to negotiate some bridges and a lock all less than
1 metre wider than the boat. I noticed that steering was less precise compared to the old set up. Reaction is slower and seems more abrupt, probably because the late reaction causes one to turn the rudder further than usual.
Reactions please,
Regards,
 
Rudolf

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