Topic : Rudder Length?

Hi everyone, I'm sailing 2039 in Co. Cavan in Ireland and am still being haunted by losing the rudder in late 2006.  I got one made by a local chap here but when the boat heels on a close haul the rudder loses purchase and she noses up wind. Does anyone know is there any specific ratio for the rubber depth eg. boat length: rudder depth, sail size: rudder depth etc.  Any help would be greatly appreciated.

Posted: 26/06/2009 12:26:17
By: Rory Donnellan
Irish European Champs next year ... great plan or wot?!!

Posted: 26/06/2009 12:34:38
By: AD
Sail her flat, less centreboard and you'll have less lee helm.  Flat is fast and boat speed makes you a tactical genius as someone said.    Merlins do screw up quickly to windward if they heel.

Posted: 26/06/2009 12:45:19
By: Hike harder
I think you meam less weather helm.

Posted: 26/06/2009 13:02:56
By: Bjorn Again
Less weather helm is fine, but even with the centre board up 50% you get a strong gust, boat heels, rudder loses purchase and I'm drinking lake water, not nice!!  I don' want to make too long a rudder and clip every low lying rock in the lakes I sail.  Ans it'll reduce the speed.  What length are your rudders folks?

Posted: 26/06/2009 13:22:23
By: Rory
I did mean weather helm - stupid me.

Posted: 26/06/2009 14:04:53
By: Hike harder
I had exactly the same problem with the original rudder in 1620. With nothing to guide me by out here in the wilderness I made my own, and after a few tries have a shape that never gives trouble. If you post your e-mail address I'll send you the outline.

Posted: 26/06/2009 16:56:47
By: Rod & Jo Sceptical
This may help:-

The Milanes fixed rudder I have is 38 inches long maesured from the lower pintle - i.e. 38inches in the water and about 10 inches front to back.

If you make up a lifting/pivot rudder blade, you'll need to add in the additiona lenght for the rudder stock.

Our lifing rudder is a simple "blade" - parallel front and back - no special taper - the fixed rudder is probably a better (less drag) shape - however, sailing inland the lifting one is easier for launch/recovery.

As above, once a wider Merlin start to heel, it will have lots of weather helm - and the ruder alone can't correct it. If the boat is unbalanced when flat, then you will probably need to evaluate the rig set up (e.g. mast foot/rake/sail plan) - and possibly (bigger job) the centreboard pivot position.


Colin 3387

Posted: 27/06/2009 09:41:28
By: Colin
My Jon Turner fixed rudder is also about a metre long from bottom pintle.  It has been known to stall out but only in extreme conditions, see the link.  Profile is very similar to the current Winder but without anything fancy on the tip.

Posted: 29/06/2009 08:59:32
By: Andrew M

The problem you may have is the rudder has too much rake. Most boats like the Merlin like the leading edge almost staight up amd down, the fashion on older boats was for a rudder raked back, this is good in light winds but not so great on a windy day. Also, the advice on sailing her flat is spot on, these boats don't go well if heeled more than a couple ot degrees. Dave.

Posted: 29/06/2009 10:30:29
By: Dave
I had an uncontrolable rudder on 3542 when I first put in on the water, I tried different merlin rudders with no sucesss. In the end a out of class fireball rudder gave me total control back, it was the same basic shape as the origional, but it was 27mm thick in the centre of the curve where the origonal was only 22mm, I think it just had more presence in the water due to the extra thickness.
Dave F

Posted: 29/06/2009 20:57:21
By: Dave F


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