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Go Back   SailNet Community > General Interest Forums > Gear & Maintenance
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  #41  
Old 09-21-2007
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It occurred to me in the shower just a bit ago that this mainsheet problem is more than a speed or convenience issue. It's a safety issue, as well.
Yup - mainsheets are a pretty important part of the boat. FWIW, I don't know anything about your rig but I have 1/2" line on a 30 foot with mid-boom sheeting and I definitely would not go smaller. The small stuf digs into your hands and if you do need to run it through the winch - it doesn't hold as well on a self-tailer (unless they are small as well..)
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  #42  
Old 09-22-2007
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Quote:
Originally Posted by Giulietta View Post
And you can, if you really want it to be butter smooth get this for the boom



This for the traveller...again inverting the cleat..



and VIAGRA for the block

I have the Garhauer version of these, and I am putting in a Garhauer two-metre traveller with double blocks this winter to replace the stupid Harken the previous owner thought was adequate.

EDIT: I like and use Harken stuff, but the about-to-be-former traveller has little cars with pull-up pegs that drive me nuts. I may recycle it for a pole track on the mast front, where I won't care so much.

Last edited by Valiente; 09-22-2007 at 01:07 AM.
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  #43  
Old 09-22-2007
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Talking Up My Peeps...

Look at Garhauer--they've always done me right. Almost everything I have had to replace (one piece at a time, I assure you) has come from there. Good prices, no complaints, prompt shipping.

If a company does me right I'll tell anyone who asks.
If a company does me wrong, I'll tell everyone who'll listen.

Nebo
MacVen 222
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  #44  
Old 09-22-2007
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Update.

Stopped by West Marine. Gotta be careful there, because sometimes they may sell you the Wrong Thing. Case in point: The Admiral and I stopped by one that's near our boat, and they were happy to sell us a Harken 2602, which is right for our boat, and a Harken 060, which, tho it's also a 57mm (fiddle) block, is undersized for our application. Harken recommends, for our needs, a 1566. The critical difference being an 1800 lb. safe working load, vs. 500, and a breaking strength of 5000 lbs, vs 2000.

And I forgot the "Viagra" for the fiddle block!

Hopefully, one of the WM's close-by, or maybe Mike's, will have the fiddle block we need, so we can get this stuff installed this Sunday.

bobmcgov,

The cordage is actually in fine shape, and of the right size (3/8").

Boasun,

Re: Cordage too large. Could be. Could be the original cordage was 5/16", rather than the 3/8" that's on there now.

Wayne25,

Yes, others have mentioned the load issue. I'll make sure to double-check the attachment point on the boom. Thanks for the heads-up.

Sailormann,

Problem is, the blocks we're looking at won't all take 1/2" cordage. The double that's going on the boom, if we stick with the Harken we now have in-hand, takes a max of 7/16". The Harken fiddle block they say we need will take up to 9/16". The Lewmar fiddle blocks Alex recommended I think were max 3/8". We have what appears to be 3/8" on the boat, now, and it's in good condition. I think we'll give that a go with new blocks before looking to replace that.

Thanks, everbody, for your comments.

Jim
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  #45  
Old 09-22-2007
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Just looking at it the blocks may be a bit small, but the previous owner used them seemingly to race.
Just looking at the design of such cleats - they are half tear drop. With full strain the length holds the rope. However as you pull it to you it should just hold on the widest few points as it opens up, then you can lift it.
There is a spring inside but I doubt that even if that is overtightened that would not be overcomeable.
If the rope is the right size ie just gripped at the widest part, then if I remember correctly the jaws can be adjusted so that when not undertension, only that part grips. From the photo it looks like most grip when under light if any tension, although it is difficult to tell. If so it is possible that under tension, only the flats hold so the curved wider bits cannot operate to open the jaws when pulled, and you would be pulling against the full holding strength.
However adjustment there only solves part of the problem since you can't pull it in anyway.
I wonder if you don't have the traveler set low ie to leeward on a beat. If you have it at roughly the angle of the boom then in effect the mainsheet simply pulls down on the boom. In any wind it will become impossible to move simply because you are trying to just pull the boom down against the sail.
Shift the traveller up and you are mainly pulling it in not down, and the load is less.
The traveller in effect governs in out while the mainsheet governs up down and in out depending on position.
When the traveller is low the mainsheet pull is down. This flattens the sail but also tightens the leech reducing twist. Twist allows the top of the sail to fall off and thus reduce heel. The wind at the top has a greater moment ie heeling effect. Depending on the wind some twist is desirable.
You might try getting the boom angle first with the traveller, then adjusting the shape for the wind with the mainsheet. Then in increasing wind you have the options of flattening via more mainsheet, or increasing twist by raising the traveller or easing the main. Some say you play the traveller not the mainsheet normally. However the two interact so it isn't quite that simple, however that may give you a start.
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  #46  
Old 09-23-2007
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Oops. Just looking at the loads using the various calculators available, you could have gotten away with that system in 15 knots with it at the end of the boom, however as it is the load would be 630-730 lb depending on if it is 5-6 ft from the end about 75% more. With the traveller taking 20% that appears to give you 80-100 lb load on a 6 purchase system. With the existing load you would be unable to release the tension to free the sheet. 80-100 may still be more than desirable and you may want to think about shifting the traveller.
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Old 09-23-2007
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Chris,

Thanks for the comments and explanations. I'll have to make a note of your explanations about twist vs. traveller position vs. the mainsheet. Interesting stuff.

I come up with 497 to 559 lbs. in 15 kts on Harken's mainsheet system loading calculator. (Depending on how far the mainsheet attachment really is from the end of the boom. I'm just guessing 3-4' atm.) That's 125 - 140 to the operator (99-112 lbs, assuming 20% to the traveller) on a 4:1 system. I should be able to move that. Don't know about my wife, tho. There's only one way to find out: Buy the new blocks, put 'em in, and give 'em a go. I would really prefer to avoid a 6:1 system if I can. I think next I'd try a 5:1 system.

One thing for certain: I'll not be buying any new cordage until I find out. I'd hate like hell to buy new cordage for a 4:1 system, only to find I need a 5:1 or 6:1 system. I think there's enough 3/8" on the current one to go to at least 5:1 - maybe 6:1. It turns out that the PO used to use the winches, just as Sailormann suggested. Of course: He always had a racing crew--with one guy just to handle main and tactics. The Admiral and I don't have that luxury.

That Harken calculator came up with 1990 to 2239 lbs load in 30 kts. But I'd be operating with at least one reef in at anything over about 15 kts. So I should be good with SWLs of 1800 and 1584, right?

Jim
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Old 09-23-2007
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I took the length along the clew as 11' 10" from a sailplan somewhere and the length back from the clew as 5-6' but just as a guess.
If the real wind is 15 I calculate thatthetotal sail area on a beat needs to be reduced by a third for each 5 knot increase in real wind so with 30 knots you reduce sail area by 75%. This is from the working sail area ie no number 1 genoa. This is because the force is related to the square of the wind speed and takes 15 knots as the optimum setting.
I don't know how strong you are but pulling say a 100 lb is two bags of cement. I would find it difficult to do repeatedly, especially one handed.
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  #49  
Old 09-24-2007
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Quote:
Originally Posted by SEMIJim View Post
Chris,

I come up with 497 to 559 lbs. in 15 kts on Harken's mainsheet system loading calculator. (Depending on how far the mainsheet attachment really is from the end of the boom. I'm just guessing 3-4' atm.) That's 125 - 140 to the operator (99-112 lbs, assuming 20% to the traveller) on a 4:1 system. I should be able to move that. Don't know about my wife, tho. There's only one way to find out: Buy the new blocks, put 'em in, and give 'em a go. I would really prefer to avoid a 6:1 system if I can. I think next I'd try a 5:1 system.
You should be doing your calculation based on heavier wind conditions than 15kts IMHO. If the control line is 125 to 140# at 15kts; it is definitely not enough ratio. That's pulling over half of a mans body weight; all of a womans. Not going to happen for long; and if you get into some gusting wind (gusts to 30 kts) it won't be easy to spill to reduce your heel. Ideally you'd want an 8:1 to cut these loads in half; but 6:1 would probably be manageable.

It looks like you have a windward sheeting car. Chris is correct in stating that the traveler can be a more effective sail control than the mainsheet. Another thing to consider is sheeting the sail down flat with the mainsheet and then lowering the traveler to reduce heel. Doing this keeps the mainsail at minimum draft yet spilling power.

I would go with the 6:1; or possibly the 4:1 with 16:1 fine tune (shown on the Harken Tech Page http://www.harken.com/rigtips/mainsheet.php). With the 16:1 fine tune you must realize that the 16:1 control line does not have much travel so if you need to spill you are still dealing with controlling the 4:1 line.


Quote:
That Harken calculator came up with 1990 to 2239 lbs load in 30 kts. But I'd be operating with at least one reef in at anything over about 15 kts. So I should be good with SWLs of 1800 and 1584, right?
I would go to the higer range of the 30kt loads (SWL of 2500 or so). The reason is that loading is relatively exponential (double the wind; quadruple the load). So at a 40kt gust you would be seeing ~4000 lbs (don't quote me it could be higher). If you run through the compu-spec on the Pearson 30 mid-boom it kicks back P/N 1546 (Triple, SWL 3800#) and P/N 1556 (Triple with Hexaratchet, SWL 3800#); what Giu suggested earlier. Harken blocks tend to run on the small side for line diameter; we went with 5/16 line for 3/8 spec'd sheaves. For 9/16 sheaves I would use 1/2" line max.

On our boat we recently upgraded the traveler; it was originally 3:1 and impossible to move/control in winds over 15kts. So I replaced it with a harken high load traveler car and 4:1 purchase. That made it move easier but it was still lots of effort to adjust. I ended up doubling up the control ends to make it 8:1 (planned but wanted to see how it worked at 4:1); now we can adjust it in any wind condition. To minimize cordage I reeved it as a continuous loop with cam cleats placed in front of a small cockpit winch just in case we needed more leverage. We rarely use the mainsheet for upwind adjustments now.

HTH...

Last edited by KeelHaulin; 09-24-2007 at 05:38 AM.
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  #50  
Old 09-24-2007
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Quote:
Originally Posted by chris_gee View Post
I took the length along the clew as 11' 10" from a sailplan somewhere and the length back from the clew as 5-6' but just as a guess.
Pretty close. The sailplan calls for a 11.8' clew. I just called it 12'. The mainsheet attachment point is 4' from the end of the boom, which is about 13' long. (I did a rough measurement of the boom, w/o removing the sail cover, yesterday.)

Quote:
Originally Posted by chris_gee View Post
I don't know how strong you are but pulling say a 100 lb is two bags of cement. I would find it difficult to do repeatedly, especially one handed.
Everything's relative. We both find the traveler to be easy to move, wherever we want, on any tack and, so far, regardless of wind strength. So maybe we ought to be relying more on that and less on the mainsheet.

We'll give a new 4:1 system a try. If it's still too much, I'll look to increasing it to a 5:1 or 6:1 system. My goodness, it's only a 30' boat. Had one experienced sailor yesterday tell me there's nothing wrong with the blocks we have, just file down the teeth in the cleat a bit, and change the angle a bit if we can.

Jim
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