for a more modern system do a search for "Crockett downhaul"
an excellent system
I set mine up as per the diagram below (I forget who to credit for it). I'm no expert but it works okay (although I can see a requirement for more downhaul force at times). Its fool proof and will get you going anyway 
I find scrounging pulleys/blocks from cheap bins/shop specials dictated a lot of my rigging 
Lachlan has shown a 3 to1 on the main sheet and 4 to1 on the downhaul(the floating pulley acts as a multiplier on the downhaul and only changers the direction of pull on the main), I use a bit more muscle and have 2 to1 on the main and 4 to1 on the downhaul. Although they aren't linked on the cat I have 8 to1 on the main and 12/16 to 1 on the downhaul
from watching sailboard setup videos it appeares that it took considerable more effort with higher ratio block systems to get the mast curve. do you not load the mast, inducing curve and flatting sail as much?
I would expect the to straighten and recurve on each tack or sheet adjust of a few inches.
Any video around to show mast rack during mainahewt adjustment?
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Try this www.seabreeze.com.au/forums/Land-Yacht-Sailing/Construction/The-Crockett-Downhaul/ should get you where you want to go.
Cheers Col
www.seabreeze.com.au/forums/Land-Yacht-Sailing/Construction/The-Crockett-Downhaul/
Well I don't know how you did your search but I just found three Threads with the Crockett DH System in them.
Have a look at the one above as it has an excellent photo of what you are looking for.
Ron
Slightly off subject but this blurry shot is about to be fitted into my boom as an outhaul system.
Top block ties onto the sail. Other end of the yellow rope ties to the boom externally. End of the green rope ties to the inside of the boom. And the end going through the cleat is tied onto shock cord. Oh and the whole lot is stretched out over about a meter.
Cheers Col
Previously, "from watching sailboard setup videos it appears that it took considerable more effort with higher ratio block systems to get the mast curve. do you not load the mast, inducing curve and flatting sail as much?
I would expect the to straighten and recurve on each tack or sheet adjust of a few inches."
The Crockett downhaul provides a number novel solution; 1) It allows a sustained pre-tension on the downhaul with a lesser additional tension from the mainsheet.
Two double sheeve blocks, one with becket; rove to advantage with bitter end secured to a cleat. (If rigged true vertical it will decrease the boom tension on the mast reducing side load on mast. A line to hang the mainsheet turning block off the mast would reduce clutter in cockpit.)
www.seabreeze.com.au/forums/Land-Yacht-Sailing/Construction/The-Crockett-Downhaul/
Considerably different than some of the others pictured on various landyachts.
Col: 'Top block ties onto the sail. Other end of the yellow rope ties to the boom externally. End of the green rope ties to the inside of the boom. And the end going through the cleat is tied onto shock cord. Oh and the whole lot is stretched out over about a meter.'
It is nice you have the fittings to run your outhaul forward inside your mast. Unless it is a monster sail and you are limited in arm strength, maybe you might want to consider losing the second line and block inside the mast. You could lead the line back aft from the exit block fitting to a small cleat, conventional or a jam or clam.
Need to adjust pull on the line, too much resistance for you; head up unload the sail (luff) and make a quick overhead adjustment.
Mike there is no need to per-Load the Mast it is cut into the Luff and as the Main Sheet is hauled in the mast then takes on the shape in the Sail Luff pocket. One advantage in this method is that the tension on the mast is not constant and allows the Mast to relax when not sailing.
Ron
I have a V cleat on one end of the downhaul lineand put a bucket of pretension on the mast. learnt that trick years ago , forgot it with centresheeted class5's, was reminded by blokarts,and now use it constantly
there is no need for a line off the boom to support the sheetrope block , it always floats on the midpoint as soon as any tension comes on ( we tried it)
That outhaul with 1:1 and 4:1 looks like just the thing, but can you reach it when sailing?. perhaps consider a dual highfield lever systemI will post a photo)
PRETENSION????? You are PRETENTIOUS??? Paul [}:)]
I love reading about other Folks (Globally) and their writings. I like the insight into their thinking and also the Colloquial terms that are similar or the same as us Ockers use. Interesting to say the least as well showing that all our Butts Point Downwards.. Any other way and I would have to accept that there are Gods..
Ron
Here is the set up on my class5 boom
It has an internal car with two curved rollers that ride on the inside of the boom
Between the rollers is an attachment for the clew of the sail that slides forward and back in a slot in the top of the boom
Behind the car and attached to it are three sheaves and fixed to the rear of the boom
and inside it are another three sheaves with the outhaul line exiting on the underside
of the boom and passing through a jam cleat and finishing in a plastic ball
The bungee loop showing stops the outhaul ball flailing around when close hauled
The mainsheet system is not that far back when sailing !
The car is pulled forward by strong bungees 3x5mm dia and fixed at the front inside the boom These could actually be stronger
Some people have used skateboard wheels for rollers but these ones are solid
white plastic
View of underside of boom
Photo's are all well and good, Hiko but in the case of the very slow of whit how's about you do a couple of schematics for us??
Ron
Hiko
Do you need shock cord to take the tension off the sail along the foot? I was hoping to outhaul with the blocks and let the wind take the tension out again. I'm using a Laser dingy 'racing' clew strap which slides really easily but is that enough? Problem I have is all this work can't be tried out till Elvington opens again at the end of February
Cheers Col
I use a 4 wheel car on mine but the pulley system is much the same as Hiko's.
Now I only have a 2:1 ratio and seems good enough. The wheels are scavenged from sliding door hardware. They usually last a couple of years if hosed out after each sailing session.
Colk I would run with Clemcos setup if you can it looks easier to make and the
extra sheaves I have are probably not necessary and would require less bungee strength
I would add an extra hole at the top of the car for a split ring to stop the car dropping out of the slot when the sail is not fixed to it
Mine has this but doesnt need it as the rollers are near full diameter of the boom
Not sure what type of rollers are used on sliding glass doors in your area, but I have used the sheeves from replacement roller to make up small blocks in the past.
This will give some configuration ideas:
www.technologylk.com/__1740/sliding-glass-door-roller-assemblies.html
Individual BB nylon sheeves available as well.
'in the lower 'other Southern California'
My outhaul is pretty basic stuff, and little talent is needed to add it. I have 4 sails thai can all use this boom, and I don't have anywhere near the required talent to make an internal shuttle work
This works just fine, tho.....
Ain't nuthin wrong with that Yank. If it works it has to be good. Works fine is excellent. Thing is I can't see the reasoning behind Out Haul of that magnitude??
Me Musckles is Strong enough.. Yup! An' I eats all me Spinach as well.
Ron
PS: I yam what I yam and that's all I yam..
I Agree nothing wrong with that system I have simpler systems than that on my minis
The roller car system though is hard to beat for easy adjustment while sailing on different points on class5
Different Horses for different courses as they say
I need the outhaul to be adjustable on the move because the runway I use is narrow but 2 miles long...2 miles is a long way to come back with the wrong sail tension. And if it's right going out it ain't never right coming back.
Is what I've ended up with. Just got to get out and get the position of the knots for the sheet and shockcord sorted.
Cheers Col
