LEEBOARDS...Re: [Michalak] Two leeboards for the ladybug?
- Lift and/or leeway prevention of the foil/keel depends its characteristics of size, aspect ratio, coefficient of lift, angle of attack, and speed. So, the faster the sailboat the smaller the underwater foil required to have the same lift - within reason, other variables not withstanding - this may mean a boat with a large sail can get away with a smaller board, and that with a smaller sail it might need a larger board. A larger board of equivalent design except for size incurs more drag. What applies here to boards applies to rudder foils too.
Downwind courses don't require as much lift, or even none, from the board as courses to windward. Also, raising the board moves the clr aft relative to the coe such that rudder input and so its drag is less too.
--- In Michalak@yahoogroups.com, "jhargrovewright2@..." <jhargrovewright2@...> wrote:
> Daniel, Most boat designs have too much leeboard. Faster boats need less leeboard area as a rule. I would suggest that reducing the amount of board is not causing more leeway but is allowing you to go faster? Watch the tactics of a very competitive class boat racing fleet....and watch them raise and lower the centerboard often depending on the point of sail. Unless you are beating into the wind you likely have too much leeboard in the water. I have tested my speed against many boats and found on a beam reach to a run most boats are faster with little to no leeboard in the water. That is counter intuitive and it was hard to accept crabbing down the course sideways, but significantly faster. I have tested that premise many times and I still do not understand. Also raising the rudder to just enough to steer will also speed the boat up.
- Great information John Boy and thanks for sharing. The bronze ring and
larger blocks I will certainly take into consideration and ain't the
truckers hitch a great knot?
--- In Michalak@yahoogroups.com, John Boy wrote:
> I've only sailed lug rigs and LOM's and I returned home yesterday from
the FL120. Â My wife and I sailed our Normsboat about 150 miles over
five days. Â We went a day early to get a little more sailing in
before the event. Â We built Happy Adventure in a hurry starting in
mid February and finishing up, really stopped building, about two weeks
ago. Â Oil base paint takes awhile to dry you know. Â We borrowed
the 16 foot mast from my PDGoose, the 91 sqft lug and LOM mizzen from
Looney Toon, our Toon2.
> Here's how I do it. Â On my yard I've lashed a 1 1/2 inch bronze
ring that I pass my halyard through and then clip it on the front of the
yard. Â For my downhaul I use a trucker's hitch. Â My main is
polytarp and three years old and pretty much blown out so I had to add a
vang to try to get some tension in the leech. Â The sucker flapped
the whole trip. Â Anyway, something to consider is getting some
larger blocks for the sheets. Â I've been using small Racelite blocks
from Duckworks. Â They work fine but a friend of mine was parting out
an old beach cat and gave me a bucket of old blocks. Â A little Reel
Magic spray and they were as good as new. Â Much faster and less work
when a gust hits you.
> I have yet to add jiffy reefing to it. Â One of these days I will.
Â On HA's first sail we managed to survive winds 25G35 with no reef.
Â Maybe that's why my main is stretched out. ;)
> BTW the Normsboat is best described as a baby Dovekie. Â Mine's
modified in a couple of ways. Â First to the cockpit, I added 6
inches to the cockpit length and a two foot deep bridge deck. Â I
opted to leave off the motor well. Â Later on I'll add a trolling
motor for getting in and out of the landing. Â
> John Boy
> I have a blog! Â http://toon2sailor.blogspot.com/
> âSeaward ho! Hang the treasure! It's the glory of the sea that
has turned my head.âÂ
> Robert Louis Stevenson, Treasure Island
> [Non-text portions of this message have been removed]
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