Re: [bolger] Micro rudder
- On Sun, Nov 7, 2010 at 12:35 PM, rod_cahill <rod_cahill@...> wrote:
>You mention 'cabin' not 'cuddy'. Are you building the cabin version,
> I am now at the stage of making the rudder and tiller but thought it best to consult the brains trust first. Does anybody have any improvements on the stock standard bolger rudder/tiller assembly that they can share with me? Any problems with the standard setup?
> Also, my micro has the mast setup on partners built into the bow like the long micro and the foredeck will be built in with access from inside the cabin. I am wanting to see a picture with the exact placement of all cleats, blocks, etc on the foredeck so I can fit them before closing off the deck. Thankyou.
> Rod Cahill
> Bowning (near Canberra)
> New South Wales
the Navigator Micro?
My opinion is that the rudder tiller cannot really be improved from
the plans. (There is a bit of a detailing issue of making the hole
shroud through the bulkhead tight from outboard engine exhaust).
The rigging and sheeting of a Navigator Micro rig depends on the
detailing of the cabin windows, and the choices you make for the mast
stepping and this gets complicated quick.
- 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