Re: Micro rudder
Good point, and I modified my mast a bit two years ago in an attempt to induce some lee helm, to counteract the weather helm.
BUT, I thought I would need to rake the mast FORWARD (move the top of the mast out in front of the bow) more, instead of raking it back. Moving the mast forward, dropping the bow of the boat, raising the stern of the boat, or adding a headsail would all help induce lee helm, yes? Or did I read this incorrectly (in which case I should be raking my mast aft, towards the stern of the boat).
Ja? or no?
--- In firstname.lastname@example.org, "Myles J. Swift" <mswift@...> wrote:
> This discussion has got me wondering if maybe you might need to rake the
> mast back a bit. On my Micro it takes a good strong wind ( over 20 for sure)
> to develop any weather helm if the mizzen is not doing anything. I used to
> have a hard time getting people to believe it had so much lee helm without
> the mizzen in play.
- End plates help a low aspect ratio rudder, if it's shoal water you're after, but a high aspect ratio reduces drag the most. The high aspect ratio rudder can be smaller and you will get some reduced helm effort. For more greatly reducing helm effort, the "balanced" aspect of a rudder is more important. You can mix and match - a low aspect rudder can be balanced to get low helm effort. You're arms are happy, but the rudder is draggy and the boat is not moving as it could. - Bill
From: email@example.com [mailto:firstname.lastname@example.org] On Behalf Of etap28
Sent: Sunday, November 14, 2010 10:34 AM
Subject: [bolger] Re: Micro rudder
correcting myself... actually, the high aspect rudder doesn't reduce the amount of drag, it just changes the "gear ratio" so to speak of the steering
so it doesn't have much effect on speed but it does lighten the helm drmatically... the longer and skinner the blade, the less leverage the blade has over the relatively longer tiller
--- In email@example.com, "etap28" <dave.irland@...> wrote:
>funny about those traditional catboats... if you make a high-aspect rudder, a typical modern blade, the weather helm is mitigated hugely. Obviously if you have a "barn door" sticking out the back, with about the same lever arm pulling against the tiller as the tiller is pulling back, it's gonna hurt--especially with a low aspect sail sticking out over one rail about 20 feet.
> I'll tell you what's
>Bolger actually used on a lot of his designs, you could totally eliminate the weather helm and hide that force vector in sideways torque against the rudder shaft
> Also, if you wanted to make a clever semi-balanced rudder, of a type
>cat boat types but nobody was all that interested . . . (PS I actually know first hand that it works. I've had a few catboats, including a Woods HOle Spritsail boat, one of about 3 in existence, and I made a nice foil shaped kick up rudder for it and it sailed like a bullet... the absence of massive weather helm obviously gets rid of a lot of drag).
> I used to preach this all the time to the traditionalist