Twin rudder adjustment Sunfast (26)

[windhond]

Hey i am Since last year the happy owner of a Sunfast 26 WINDHOND. We are sailing in the Netherlands. 
the alignment of the two rudders can be adjust with the ball joints behind the bulkhead. Does anyone know what the best alignment is? Parallel or  the rudder tips somewhat in or out? 
when i sail downwind i hear a nasty vibration. 
there is a very less play in each ridder shaft. 

[MalcolmP]

There is a recommendation on setting up twin rudders by the designer Marc Lombard of the Sun Odyssey 35 that still should be relevant to your Sun Fast 26

www.jeanneau-owners.com/hintsandtips/SO35swingkeel.html

[windhond]

Manny Thanks Malcom. Good find:) Most experts say parallel. However with downwind there is a nasty vibration. So my idea was that tips somewhat in or out could help.

Annyone the same experence? 

[Fastrak]

The rudder vibration is probably nothing to do with the toe angle. The trailing edge is quite thick and so cavitation off the trailing edge is easily induced. By sanding off one side of the trailing edge corner, which makes the trailing edge slightly asymmetric, will probably solve your vibration problem.

For rudder toe angle, what you are doing is trying to achieve minimum drag on the windward rudder. The leeward rudder is doing most of the work and the windward rudder is the drag inducing parasite. The toe angle to achieve minimum drag will be a function of both boat speed and heel angle which both affect the way the water flows from the back of the hull, and so the optimum toe angle is never constant. On my twin ruddered Sun Fast 3300 the optimum toe angle is "toe out" down wind and "toe in" upwind. Toe in is when the leading edge of the rudders are closer together, and the reverse for toe out. I have the luxury of a toe angle adjuster system which is obvioulsy not the case for most twin ruddered boats.

[hielkesw25aquilanl]

Sailing a SO26 Zeekat, also in NL (they are basically the same boats) -my profile pic shows the previous Jeanneau SW25 :-)
Our rudders are in parallel and no vibrations there. Just acquired the boat this spring, but it was the club-ship of our WSV so I've known her longer...

1) You might want to switch the engine's gearbox in reverse when sailing (with no engine on)
Could be that the iddle free spinning prop under sail causes the vibrations.
I can measure our rudder distance in fall, when back on the hard if you like?
We have a berth (and also winter storage) in Aalsmeer.

2) I've noticed over this summer trip that the SO26/SF26 rudder arrangement easily fouls with seaweed and assorted debris. Are yours clean?

Fair winds, Hielke

[melbourne]

Aug 4, 2020 21:02:31 GMT Fastrak said:

The rudder vibration is probably nothing to do with the toe angle. The trailing edge is quite thick and so cavitation off the trailing edge is easily induced. By sanding off one side of the trailing edge corner, which makes the trailing edge slightly asymmetric, will probably solve your vibration problem.

For rudder toe angle, what you are doing is trying to achieve minimum drag on the windward rudder. The leeward rudder is doing most of the work and the windward rudder is the drag inducing parasite. The toe angle to achieve minimum drag will be a function of both boat speed and heel angle which both affect the way the water flows from the back of the hull, and so the optimum toe angle is never constant. On my twin ruddered Sun Fast 3300 the optimum toe angle is "toe out" down wind and "toe in" upwind. Toe in is when the leading edge of the rudders are closer together, and the reverse for toe out. I have the luxury of a toe angle adjuster system which is obvioulsy not the case for most twin ruddered boats.

[melbourne]

Hi, 

I am in Australia with a Sunfast 3200, launched 2016. I am curious about how the variable toe works on the 3300. If its standard, I can look at one, there is a 3300 in the yacht club near mine (my club is in Brighton in Victoria/Melbourne Australia). 

One thing I do not like about the 3200, is that the rudder turn angle is restricted compared to most boats. My rudders only turn 40 degrees. This makes the boats turning circle poor, which makes it more difficult to park it in my marina. I'm wondering how easy it might be to increase the turn angle of the two rudders ...