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Old 08-11-2010, 16:07   #1
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Main Sheet & Traveller Redesign

One of the items on my list of projects is to rethink our main sheet system. As background, she's a heavy 32', displacement probably around 10500. She was designed with a relatively low aspect ratio rig (that is relatively stubby mast with a long boom: P=32 E=13.8) However, her current main sail is a high aspect ratio sail that is the right height, but ends about 3'-4' short on the boom. It is a flat, fully battened sail with almost no roach. Sail area is supposed to be 220 square feet, but I believe the way it is now to be closer to 180 sq. ft. But I digress.

The mainsheet system is a 4:1 system on two fiddle blocks, the bottom one having a cam cleat for locking. It has a single boom point attachment, about 6" from the end of the boom (a ~8" "t" shaped plate slipped through a slit in the boom and riveted at ~ 8 points). There is no winch for the main sheet. As we're not racing (and never will on this sturdy girl) this simple system works for us, for now. We may reassess once we've had the boat for a while longer. The 4' traveller is aft of the cockpit. Here is where the two problems crop up: the lower fiddle blocks are held on with the tiniest of lightweight shackles. This is not OEM and I do not trust it (granted, it has survived for likely 15 years). Also, the traveller is not controlled by a line, but by two "stops" which you can slide along the track and lock into place. I find this very slow and cumbersome to use.

(sorry, I have no detailed photos of the system. The ones attached are from the original inspection.)

We were recently gifted a used traveller track and matching car, in good shape and significantly beefier than the one we have. It is the identical length to the one on the boat, and will fit perfectly. It will allow for a stronger attachment point to the sheets, as well as the possibility of adding control lines (the old stops wouldn't fit the new track anyway).

Q: How would one design the traveller system? The cockpit edges are teak and though adequate for leaning on, will not be strong enough for the weight of the fully loaded main. Would a 3:1 ratio be enough for the traveller? If we up the sail size to spec, would that still suffice?

I'm thinking of adding a cheek block with a becket to the car. I would run likely a line from the becket outboard to a block mounted somehow at the ends of the tracks, back to the cheek block on the car, then slightly aft of the track to a block that will redirect the line just outside of the cockpit with a cam cleat. See my nifty diagram (sorry, only a few minutes to make it up!)

Any other ideas on how to design for this setup?

Q: Is a one point boom attachment adequate? I understand newer models have gone away from this system. Though I get that it may be superior, is it necessary? What we have seems to work; if it ain't broke, don't fix it?

Hope that was clear! Thanks!
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Old 08-11-2010, 16:11   #2
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I think that 3:1 is not enough..... but we all have our opinion
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Old 08-11-2010, 16:17   #3
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And thanks for your opinion! If 3:1 on a traveller won't do, how else would you suggest running lines for it on our configuration?
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Old 08-11-2010, 17:12   #4
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Try logging onto Harken.com and go to the Compu Spec section. They have almost any boat listed and will lead you through what you may be looking for. This site has a lot of great ideas and configurations. They also have the specs for your boat and calculate the expected loading forces. This assumes you have the original rig. I know most of the top manufactures also have similiar help sections on their websites.

Give it a try.
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Old 08-11-2010, 17:22   #5
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I have just about the same set up as you on a 13000lb 35 footer, those stops are a bit of a pain, your travler set up looks like it should work, but unless you are planning on pulling to windward I would think a triple on the travler is a bit much as the stops were just to limit full run, as one on each side 1 hole in __[]__ __ __ __ __[]__or
2 holes in __ __[]__ __ __[]__ __
travler will just slide back and forth just not as far, with the purchase you can fine tune without luffing or tring to pull the travler then move the stop
As to a triple on the sheet, if you can pull it, go for it, I have a 4:1 on mine, I don't want to pull that hard, had a 3:1 and a winch but that was overkill and that the winch was on the cabintop it was hard to work,
As to the boom attachment, it's spread over 8" of the boom, that should be plenty strong, mine is just through bolted in one spot with a hoop.
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Old 08-11-2010, 17:26   #6
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Quote:
Originally Posted by serah View Post
And thanks for your opinion! If 3:1 on a traveller won't do, how else would you suggest running lines for it on our configuration?
Same path as your schematic, but one more "stack" of sheaves. My CAL28 with Harken traveler has what I describe, and my GF still cannot pull the car to windward alone under a full sail. We have developed a tactic; when I'm at the helm, she will flip the tail back to me to pull for her. Your sheet is further aft on the boom than mine (mine is middle of the boom), giving yours more leverage.. perhaps someone with better mathematical abilities than I, would care to opine as to that leverage's ability to negate the extra 2x?
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Old 08-11-2010, 17:28   #7
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Thanks for that tidbit gulfstar!! I was blown away that they had our vessel there. I'll be sure to do some digging on that. Thanks again!
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