Earlier I promised pics of the wind vane I'm building. Here we go( I hope)
The book is by Bill Belcher-
(http://data.sailboatowners.com/photos/1235672561.jpg)
Here's the table that the course setting table mounts on-This is the part that will eventually mount to the boat. That's not built yet. Everything eventually mounts to this table, and rotates within the cutout for course setting.
(http://data.sailboatowners.com/photos/1235672619.jpg)
Here's the course setting part-The vane will pivot in the two uprights
(http://data.sailboatowners.com/photos/1235672682.jpg)
Bottom view-
(http://data.sailboatowners.com/photos/1235672749.jpg)
And the vane mounted in that- The control lines run around the lower section, through the course setting table ( see the sheave?) and then lead via blocks on the quarters to the tiller
(http://data.sailboatowners.com/photos/1235672803.jpg)
and an overall shot of the whole thing, so far. Still have more to build- the mounting to put it on the boat for one thing. I also haven't added the counterbalance weights, so the vane is being held upright by that clamp
(http://data.sailboatowners.com/photos/1235672865.jpg)
Very nice. :)
Looks great Charlie, thanks for posting those
Charlie—
Just curious, but will this be a pure windvane, and not have a trim tab on the rudder, an auxiliary rudder or a servo-pendulum?
Well done looks great! Well done.
Pure wind vane- nothing in the water. Controls go directly to the rudder. Tehani steers so easily, even rail down she only needs a finger on the tiller, that it should be no problem.
And since it's being made from leftover boat building materials, it's only costing me the epoxy and my time, so if it doesn't work all that well, I can do something else. But I see no reason it shouldn't.
Looks great, Charlie.
I've been looking for a pure vane for my boat, there's somebody on the Cape Dory board who used Belcher's book to build a vane for his 25D.
Keep us posted on how well it works.
--Joe
Very nice work :) Looking forward to seeing it finished and report on sea trial
Charlie -
What is the friction between the layers of course-setting table like? What is the mechanism for holding the course setting in place once selected?
I should think some teflon, or perhaps thin bits of starboard, might be a useful upgrade between the sliding surfaces.
sail fast, dave
Very nice!! I'll look forward to reports on the sea trial as well. I'm considering my self steering options.
I'm reading "Singlehanded Sailing; the Experiences and Techniques of the Lone Voyagers" by Richard Henderson. He has an excellent chapter on the gamut of self steering options from 'sheet to tiller' to autopilot.
Todd
Hi again, Charlie:
I ordered Bill Belcher's book from the local library--and it arrived yesterday.
Perhaps this board's engineering types can correct me on this, but I've reached a disappointing conclusion after going through the first several chapters:
It seems to me that a "pure" windvane simply wouldn't generate enough power to steer a boat like mine, with its full keel and keel-hung rudder (takes too much force to move the tiller). I would probably need to use a servo-pendulum windvane, which is beyond my capabilities as a builder--and which I'd just as soon not have hanging from my transom.
So, I'll probably just stick with my autopilot (thanks again for the wiring, Dan), and continue my weird experiments with sheet-to-tiller steering.
--Joe
??? My boat is full keeled and has a keel hung rudder. I steer, even rail down, with one finger, two at the most- she has a VERY light helm, but still with a tad of weather helm.
And I once sailed for 45 minutes with the tiller pilot and wondered why every 10 minutes or so I had to adjust the course- THEN I realized I had the thing in standby mode. Tehani was holding course pretty much on her own. :D
A boat like that should steer easily. Perhaps you need to see to your mast rake?
And sheet to tiller is nothing to sneeze at- we've had sheet to tiller steering for several days at a time offshore. Works well once you dial it in.
Charlie,
Thanks for the words of encouragement. I probably have to tweak my sail balance (and possibly the mast rake) a bit--I don't have an adjustable backstay, so once it's rigged, I leave it alone.
And yes, sheet-to-tiller (STT) works pretty well, especially upwind. I experimented with it for two seasons, but with my Raymarine ST2000 installed last season, I never bothered to hook it up. I've tried several different STT arrangements, one using the mainsheet and one using the jibsheet, which I cross to the windward winch.
The latter seems to work best, but I'm having trouble eliminating friction.
Anyway, I've never tried it for more than an hour at a time, because of traffic or course changes. I've almost never taken my boat offshore. My longest offshore passage in this boat was under power (dead calm).
--Joe
Quote from: Oldrig on March 07, 2009, 05:36:04 PM
Thanks for the words of encouragement. I probably have to tweak my sail balance (and possibly the mast rake) a bit--I don't have an adjustable backstay, so once it's rigged, I leave it alone.
Us also- once set it's it's left alone. And down here we sail primarily with our working jib due to our stronger winds most days. I think we've only used our genny twice- coming back up Matagorda Bay which is almost always DDW. Oh, and of course over in Florida where they tend to have light air most days.
QuoteAnd yes, sheet-to-tiller (STT) works pretty well, especially upwind. I experimented with it for two seasons, but with my Raymarine ST2000 installed last season, I never bothered to hook it up. I've tried several different STT arrangements, one using the mainsheet and one using the jibsheet, which I cross to the windward winch.
The latter seems to work best, but I'm having trouble eliminating friction.
Friction is the bugaboo for sure. I use Harken bullet blocks- they are cheap enough in small sizes and work well.
Picture shot on about the 2nd or 3rd of July im Matagorda Bay. Normal winds
Quote from: Oldrig on March 07, 2009, 03:31:23 PM
It seems to me that a "pure" windvane simply wouldn't generate enough power to steer a boat like mine, with its full keel and keel-hung rudder (takes too much force to Joe,move the tiller).
Joe,
Do you have John Lechter's book? I don't know about Belcher's, but in Lechter's book, he outlines how to measure the yaw resistance of your boat. In his engineering analysis, this is the key metric that must be known before getting too far into gear design...that is, before you worry about rig tuning and balance issues.
Further, according to Lechter, there is no way to 'just know' your boat's yaw resistance without measuring it. If I recall correctly, he gives some numbers like "if you boat's YR is between x and y, she'll self steer pretty good...if less than x, you need to do this, and if greater than y, you'll need to do that."
In other words, before you write off your boat, measure the yaw resistance (probably pretty good for a full keeler), which is not hard. At least then you will know if you are starting with a good platform and if not, which direction the corrections need to be made (aux rudder, servo, etc).
Hi Capt.:
Yes, I've got Letcher's book. And (don't tell anybody), I actually made a photocopy of Woas' famously unavailable book. Belcher's seems to be the simplest of the three, but I am one of those guys who took an extra year of Latin to avoid advanced mathematics in high school. (Well, it did help me read most Romance languages--but I wish I had taken some calculus.)
Anyway, I'll have to study Belcher's book carefully. It contains detailed plans for the vane that Charlie posted in this thread--and it looks like it might work.
Charlie:
I sail primarily on Buzzards Bay, Massachusetts. It's an area with a well deserved reputation for strong, gusty winds that pick up in the afternoon. Since the bay is relatively shallow, and since it has a strong current passing through it, we also get "square waves" when the wind and current are in opposition. This makes downwind sailing very hairy--and probably unsuitable for most self-steering gear.
Still, I got into this quest after soloing for 60 miles (9 1/2 hours at the helm) without a break. Never again! At least I can now use my ST2000 for the stretches under power. But self-steering under sail remains an elusive goal. I think a horizontal-axis vane linked directly to the tiller could provide the answer.
If my job disappears (not unlikely in the current climate), I just might have the time to clean up my workbench and get to work on one.
Spring is coming! Fair winds to all!
--Joe