Fedor
It is always good to get feedback on Campaen.
Some comments on your observations:
On the 18m proa in winds below 10kts we usually set the trailing rudder to almost fully counter the weather helm then steer with the leading rudder. In higher winds the leading rudder is usually set inline and the boat steered with the trailing rudder. Although in some sea conditions it is beneficial to use both rudders.
During a shunt we come into the wind until the sails luff, even when sailing downwind; swing the boom to stop forward motion and start moving in the opposite direction. Once speed is above 3kts we begin coming onto the desired course, bringing the boom in to keep sails working efficiently. I have found it is easier to get in irons during a downwind shunt than upwind shunt because there is no dagger board down and tendency to start the shunt with wind abeam rather than on the nose. One of my observations is the sail CoE moves a long back on the rig when it presents as a flat face to wind compared to when it works as a lifting wing. Hence if the sheet is pulled on quickly it creates a large moment and the boat actually turns under the rig into the weather rather than the rig turning in the air.
When Nol considered hydraulics I think he only looked at cylinders. That would limit the amount of rotation so he wound need bi-directional rudders. The orbital/pump motors now on the 18m proa work better than I expected in a simple closed circuit. There is a little notchiness that is most noticeable on a cold morning when there is likely a net partial vacuum in the circuit but the notchiness goes away as the temperature rises. It would not be difficult to have an accumulator that keeps the system at a positive pressure but only a consideration at this stage.
Rick
On 29/04/2016, at 1:09 AM, "fvonballuseck@gmail.com [harryproa]" <harryproa@yahoogroups.com.au> wrote:
Dear All
Had a chance to Sail on Compaen/Blind Date last year when the new rudders had just been mounted - these were my notes:
Personally I was really impressed with the system - the boat steered easy - no creaks, groans, sloppiness or anything - much better than before. If anything it looked heavy - but as shared by Rick the forces are large. With the rudders mounted further to the end it did seems to turn easier than before.Some of my notes- rear rudder had a tendency to 'run away' - it would not stay straight so needs a lock which it did not have yet.- boat still had a tendency to luff / was hard to bear away when close winded at low speed - it is a fine balance. Crude way - rear rudder straight - front rudder 30-40 degrees to lee - will loose flow connection but at some point 'bites' - seems the way it was most used - thought was that the drag from the rear rudder would stall the boat. I did not spend enough time testing but tried more a slight steer from the rear and careful steering with the front (maintaining flow) - a bit tedious but better in the end to develop the feel. This is not yet comfortable for tight situations - guess the real solution here will be the schooner rig - which will allow to stear with the sailpoint as well.- I am not such a fan of fairly deep rudders which you can not lift in shallow draft environments (although they will kick-up) - but that is a design choice with conscious pro's and con's.- The 'gear boxes'/ rudders are far forward with significant extra surface - so with more (especially short) waves it should get wet with quite some breaking/slowing down, and reducing the advantage of 'wave piericing'- If I remember correctly Nol looked into (and preferred) hydraulics but could not find what he needed/trusted.- the ability to use the rudders at 90 degr to the boat in the harbor, combined with a engine that turns sideways is a revelation combined with the shallow draft means it is super easy to literally park the boat sideways.Let me know if there are more questions.Fedor
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Posted by: Rick Willoughby <rickwill@bigpond.net.au>
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