Re: Micro rudder
My only experience with cat boats is with my LM. I have had a few times sailing when, after an hour or two of reaching my arms got tired. Not so tired that I couldn't steer. But tired. And yes- both hands on the tiller. Not because I couldn't steer with one arm, but because I have two arms. Either the boat is overcanvassed at this point or she has two reefs tied-in but winds are in the mid-20 knot range. In all these instances the boat was moving consistently well above hull speed before the tiller got heavy. During my trip to the North Channel, in Lake Huron this summer, I had one day when Pug was reaching (with two reefs in the main, winds in the mid- to high-20 knot range, and waves of 4.3 feet to 5.5 feet on the beam) and she showed 7.9 knots on the knotmeter (and 8.2 knots SOG on the GPS). It's fun sailing and the boat is safe, but the loads on the tiller and rudder are considerable. On this particular day my oak-and-pine tiller (which was quite handsome and has a sexy bend in the tiller) began to delaminate (even though it's cross-bolted and screwed). I had to replace the sexy tiller with my old, reliable, straight tiller (which is a re-purposed axe handle).
Cat yawls balance wonderfully to windward. Downwind they require as much attention on the tiller as any sloop-rigged boat I have sailed.
And it all depends on the sailing grounds and conditions sailors and builders expect to experience. Small lake sailors needn't worry about their wooden Micro rudder.
Bill, in Texas
--- In firstname.lastname@example.org, "Eric" <eric14850@...> wrote:
> Two hands on a little boat reaching??? Down wind nearly as bad? Going to windward with a genoa jib usually produces the most weather helm on modern boats. Why so much weather helm on such a small boat? I thought the purpose of a cat yawl was to get good balance on all points of sail and not have a heavy helm.
- 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