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Old 24-08-2010, 16:01   #1
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Running Backstays Attachment Points

I am installing a deck fitting that will be a connection point foreach of our removable running backstays. I have heard before that these should ideally be positioned at about the same distance behind the mast as is the point (forward of the mast) where the inner forestay connects to the deck, hence making a neat, perfect triangle.

This would put the connection oof the running backstays outside, in front of the cockpit.

I would very much prefer to install it where it can be accessed from the cockpit but that would be about 6 feet further back than the "ideal?" triangle position.

What would happen if the location were back more?

Anybody experimented with this?

Thanks much....
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Old 24-08-2010, 17:00   #2
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If it were me (and I absolutely HATE runners!) I'd move them as far aft as possible if it meant that I could rig them so that the boom wouldn't hit them on a crash jibe.

I'd be surprised if the original rig drawings didn't specify an attachment point. Sometimes runners are considered optional equipment, so it's possible the drawings show them even though the PO might not have installed them.

Assuming you have the cutter rig? If I recall correctly, the Pearson 40 came either as a cutter or a sloop. Did the sloop need runners as well?
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Old 24-08-2010, 17:32   #3
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The further aft the better. One wants as great an angle between the runner and the mast as possible to maximize the horizontal component of the tension in the runner. Whether one can get a runner sufficinetly far aft to avoid hanging up the boom in a crash gybe depends entirely upon the geometry of the yacht but in any case, the main will get hung up. On the other hand, however, one would not usually be using the runners when one is running off and potentially threatened with the possibility of an uncontrolled gybe so that is not something one would normally be too concerned with, eh?

FWIW...
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Old 24-08-2010, 17:58   #4
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Aft and outboard as far as they'll go. You're using them to offset the force of the main..... closer in less leverage... further aft and out more leverage.
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Old 24-08-2010, 18:46   #5
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What svHyLyte said

Remember to get some good leather protection over the blocks or you boom is going to get scratched up pretty quickly.

Also, pay attention to the inner forestay tension - don't allow the possibility of inverting the mast if someone is a bit over-enthusiastic grinding on the runner.
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Old 24-08-2010, 18:55   #6
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What svHyLyte said

Remember to get some good leather protection over the blocks or you boom is going to get scratched up pretty quickly.

Also, pay attention to the inner forestay tension - don't allow the possibility of inverting the mast if someone is a bit over-enthusiastic grinding on the runner.
Question .... what blocks are you referring to? I have running backstays but I don't see how a block would scratch the boom. What am I missing?
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Old 24-08-2010, 19:03   #7
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Question .... what blocks are you referring to? I have running backstays but I don't see how a block would scratch the boom. What am I missing?
They are commonly called "Koch Blocks," after having knocked Bill Koch silly during one of his Americas Cup challenges. Rare to see them on boats smaller than 12 meters. On bigger boats, they tend to be about head high. Used to double the purchase on the runner.
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Old 24-08-2010, 20:11   #8
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Running back stay location

The Pearson 40s were all sloops as originally designed. Some owners had added removable inner forestays converting them to cutters. Ours is one of these.

The main will gets caught up in the rbs unless it is double reefed - the attachment point is quite a bit below the leech, unless that is below the 2nd spreader hence 2nd reef. Also the original attachment point was behind the end of the boom.

Leverage is not really a concern here as there is a 4 part tackle that can be brought easily to one of the primaries if needed (we never have). The former attachment point is now below an turning block and no space around except way aft by the stern rail.

I think doodles refers to the 4 part tackle a lot of boats have that tension the rbs. If not spaced out right, either the top or the bottom blocks can bang into the boom and make a mess of it...


Thanks all for the input, great ideas!
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Old 24-08-2010, 21:35   #9
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Hi there,

Running backstays should be anchored on the stern but you should consult with your local rigger if you are considering making any changes. I have attached a photo of the running backstay setup on the Farr 44 that I race on. The sheets for the runners go back to the winches that can be seen behind the helm.

I hope this is of assistance to you.

All the best,
Steve
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Old 24-08-2010, 22:41   #10
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I think OP means check-stays - not running backstays
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Old 25-08-2010, 08:59   #11
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I think OP means check-stays - not running backstays
Perhaps bewitched (or Weyalan) could more fully explain the difference between them.

Runners & Checkstays - Typical set up of runners, checkstays and backstay on a fractional rigged IOR boat Cruisers & Sailing Photo Gallery

Iíve previously read that a running backstay is intended to tension the forestay, whereas a checkstay is intended to control mast bend; but Iíve never been entirely clear on this issue.
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Old 25-08-2010, 09:41   #12
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Iíve previously read that a running backstay is intended to tension the forestay, whereas a checkstay is intended to control mast bend; but Iíve never been entirely clear on this issue.
You are correct although the terms are sometimes used interchangably. On our yacht our runners are connected to the mast just below the upper spreaders and just below the point where our spinnaker poll lifts exit the face of the mast. Ours is an IOR era boat with in-line shrouds and the runners are used to stabilize the mast and prevent "pumping", a function that would be performed by fore'n aft lowers if they were fitted. Hence our runners are properly, Check-Stays as they "check" mast displacement out of column (necessarily "bend") that could lead to Euler Buckling.

Our runners were originally wire rope connected to 4-part tackles with the upper ("Koch") Block at about boom level. We replaced the wire with Spectra line and did away with the tackles in favor of single turning blocks attached to the Spinnaker Pad Eyes that lead the runner tails to #43 secondaries. We really only use the runners when the yacht is hard pressed or we can feel the mast pumping. In any case, however, check-stays or back-stays, the further aft the better in terms of stabilizing the mast and/or tightening a fore-stay.

FWIW...
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Old 25-08-2010, 10:01   #13
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good explanation, svHyLite. By way of simplification, all a checkstay does is preserve mast shape. A runner goes beyond that by tensioning the forestay, which means that it effects the shape of the foresail as well.

Which is why you want the runners mounted aft.
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Old 25-08-2010, 11:33   #14
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Running backstay location

Thanks Gordy and all for the good explanationsotos plus ph. I think that an aft location is better than forward so no worry as to their relocation further aft.

I beliveve too that check stays (sometimes also called baby stays) are used to keep the mast from bending, usually located below the running backstays. These mostly keep a loaded inner forestay from pulling the mast too much forward and sometimes producing a "pumping" action.
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Old 25-08-2010, 18:45   #15
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Ah, no - baby stay is something else again.

So we have:

Fixed Backstay - goes to the top of the mast

Running Backstay - two of them both go to the top of the mast - one for each tack/gybe - for boats that have long booms and/or big roachy mains that wouldn't be able to tack or gybe with a fixed backstay

Check-stays - one or more stays that can attach anywhere on the mast and pull aft - used for mast shape or to react an inner forestay. Often referred to as "runners"

At the front:

Forestay and maybe an inner forestay for sails, Baby stay for mast shape
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