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Mainsheet system

7K views 24 replies 16 participants last post by  Classic30 
#1 ·
Topic for opinion, The new (to me) boat I purchased in the fall has a 6:1 mainsheet system. It's end boom sheeted with 293 sqft of mainsail. The current blocks are wore out and I've already decided to replace them.
So the question, 8:1 vs 6:1?, does anybody use an 8:1 system for their main sheet? When I run the numbers at 20knot of breeze only a gorilla would be able to sheet the main at 6:1 but I suppose I should be reefed by then. 8:1 would easier to control and adjust under normal conditions but I end up with 100' of line in the cockpit.

Thoughts/opinions, please.

John

BTW, the boat is a Goman Express 35
 
#8 ·
York, that's pretty amazing. Using the mainsail load calculator on the harken site a 600 sqft sail loads 2044 lbs in a 20 knot breeze. With a 6:1 your trimming 340 lbs?. Drop the wind to 12 knot and it's still 122 lbs.

I guess I need to grind the numbers myself.

John
 
#5 ·
a comparison......

my 150 s/f something, 10+ ft boom uses a 4:1 and needs only 75' of line to reach (near) 90 degrees. You *gotta* need more at 8:1 and a bigger boat! ;)

6:1 is prolly fine; perhaps using well-bearing'd blocks to reduce friction as much as possible? Remember.... an end-boom fixture is at the end of a longish lever with most of the load in the center and fwd, :D
 
#9 ·
total sail load,s a ton, but one end...smaller at that , will carry (less than ) half. not an NA, nor an kinda injunear, but it sure would seem the load would be mostly on mast. then the rest is dealt with by the "lever"/boom
 
#10 ·
You might want to talk to the tech guys at Harken. Over a decade ago they worked with a local yard to develop a gross/fine system for a friend of mine with an Ericson 33 (the Ron Holland design with the fractional rig and monster mainsail).
It's a 5 to 1 / 10 to 1, using stacked fiddle blocks, double-ended sheeting. Pull either one for the 10 to 1, or pull both together for the speedier 5 to 1.
Works wonderfully.

I have crewed on the boat off n on for 15 years.

My own boat has a smaller main and gets by fine with a 6 to 1 system.
As someone once observed-- it's all just Choices and Options. But, the more purchase you have, the easier it is to really enjoy sailing the boat when the pressure goes up.

Cheers,
Loren
 
#13 ·
Sandy, this is my point. I'd guess that 6:1 alone wasn't enough for your 37.5 so you had a fine leg on the end. 8:1 isn't difficult or that expensive to rig but I'm looking at about 120' of line. I could do a 6:1 with a 3:1 fine without too much trouble. The only wildcard there is teaching the crew when to use the fine and coarse adjustments.

John
 
#14 ·
Here's the Harken Manual on "Cascading" and "Gross/Fine" mainsheet handling systems: Harken

IMO - For a mainsail of your size and with end-boom sheeting typically such large 'power ratio' systems are unneeded, even without using 'winch assist'. Your 'end boom' sheeting provides a LOT of mechanical advantage all by itself. I myself raced a P30 (200 sq. ft. main) with end boom sheeting with a 4:1 mechanical advantage for many years and seldom needed 'more power' when pulling this system entirely by hand even when apply gorilla strain to the mainsheet, of course all the mainsheet system blocks were all roller bearing blocks.
 
#15 ·
I set up fine tunes on pretty much every boat I sail. I would run a 6:1 with a 12:1 fine tune on your boat, but with a very short throw on the fine tune. This gets the excess line out of the cockpit.

In order to do this instead of dead ending the line on the becket, add a simple block. On the other end attach a small block w/ becket and cam. I away from the boat right now so I can't get a picture, but it's pretty commonly done. It only gives you a few feet of fine tune, but that's all you generally need.
 
#17 ·
I have a 4-1 with another 4-1 on the back leg, giving me 16-1 for fine tune. I also have enough line on the micro 4-1 to douse the main when really windy, and pull it back in. Pretty nice when I only have a 195 sq ft. I would do the same with the OP's setup, but probably a 6-1 macro with a 6-1 micro, giving me 36-1 overall!
HEre is a picture.



Marty
 
#21 · (Edited)
I have had boats with fine and course adjusters, and that is how my current boat came. On my current boat, there was a 5:1 with a 3:1 fine tune (which amounted to a 15:1) on a 402 square foot mainsail. I ended up removing the fine tune since the upper fine tune block would rake the across the cockpit when tacking and jibing in a way that I considered dangerous. I replaced the mainsheet with a 7:1 without a fine tune. It works fine most of the time. When I really need to really flatten the sail in heavy air, I take the sheet to the windward jib sheet winch and use that for added mechanical advantage to get that last bit of tension.

Even though that system works well, I have considered adding a fine tune and reducing the purchase again. My current thinking is to mount the fine tune horizontally below the boom and hang the blocks and lines in a trampoline mesh sock (so I can see the blocks)that would be fed into the bolt rope track on my boom. The last fall of the course-tune would be led forward from the block on the boom into the sock where I would probably have a 3 or 4 to one tackle, which would be led back to the block on bail above the traveler, and as a single line into a cam cleat on the mainsheet block.

I should note that on the Laser 28, my prior boat, the fine tune was designed to work in a way that the block and lines for the fine tuner did not flap about the cockpit and could not get caught in the course portion of sheet. You might want to try to find a rigging layout for the Laser 28.

Jeff
 
#22 ·
If I am understanding Jeff correctly.........I do not recall having an issue with what he describes. Altho I may have, an in reality, I feel ANY sheet that is as long as his, or even as short as mine, one could have an issue with and arm, head, neck etc especially on a gybe getting caught in the lines. Not sure that a fine tune is the issue myself. More the design of the current mainsheet setup, be it a course only, or fine.course setup.

I do feel the fine is better for getting things set easier . I also usually try to keep the fine tune part on the shorter end of things, about half the distance tween the lower course blocks and the boom height. THis does keep that set of lines a bit farther out of the way.

Marty
 
#24 ·
Looks like you've still got 6 parts between blocks??
 
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