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-   -   reefing lines (http://www.sailnet.com/forums/gear-maintenance/71957-reefing-lines.html)

sailingtime 02-10-2011 09:28 AM

reefing lines
 
I am looking to replace my older reefing lines with some new lighter lines. It is a simple system where the line runs through the boom and up to a grommet in the leech of the sail. Is there a rule of thumb or a guideline on what tensile strength a reefing line should be? With the vast array of line sizes, strengths and costs I would hate to be under severed or unnecessarily over spending.

sailingdog 02-10-2011 09:49 AM

The line should run from the boom up to the reefing cringle and then BACK DOWN TO THE BOOM. This line has to act as both an outhaul (at least for the clew reefing cringle) and a downhaul.

The lines should be the same size as your halyard roughly, since the loads are going to be pretty similar. If you want to go with a lighter line, you can use a spectra/dyneema cored line and go down a size in diameter generally. You don't want to use a single braid line for this, since a double braid will have a lot better chafe resistance. Also, the outer braid on most dyneema/spectra core lines is primarily there for chafe/UV protection with the core of the line providing most of the strength.

BTW, a two-line reefing system is far better IMHO than a single-line reefing system, since it gives you far more control over the shape of the reefed sail.

sailingtime 02-10-2011 09:58 AM

Thanks.

BTW, I do have a double reefing systam and they run through the sail and back to the otherside of the boom.

GeorgeB 02-10-2011 07:07 PM

Below, is a photo depicting what SD wrote in his message. The object is for the boom to take the force on the line for the clew to lay next to the boom with the maximum tenstion. Getting the new clew to lay down flat can be a hassle in a single line system and easing off both the mainsheet and vang helps out a lot when setting a reef. You did not mention what size of boat/reefing line you have. The rigging specs for my boat (C34) call out for half inch dacron. I have gone down to 3/8 inch spectra on my reef #2 line to save weight. The strength/stretch properties exceed the original Sta-set that came from the factory. Make sure your line is properly sized for any clutch or cleat.

The second photo illustrates the problem with single line reefing. The reefing line suffers friction going through the new cringle, making for more tension on the tack than the clew. Unfortunately, most of the force is on the clew. I rigged a Harken Carbo Block to reduce that friction, but unfortunately, now have a point of chaffe in my system. The solution for that is to cut new exits on the bottom side of my boom, but the extra slots will weaken the boom just where you want it to be strong. One solution begets a new problem…

http://im1.shutterfly.com/media/47a0...D550/ry%3D400/

http://im1.shutterfly.com/media/47a1...D720/ry%3D480/<O:p

sailingdog 02-10-2011 07:13 PM

George—

You might be interested in one of the solutions I found for reefing setups. Goiot makes a neat block that fits in the reefing cringle and effectively turns it into a block. It looks like this:

http://adriftatsea.com/files/goiot.png

Using these would leave the line leading fair but reduce the friction in the system.

Quote:

Originally Posted by GeorgeB (Post 696752)
Below, is a photo depicting what SD wrote in his message. The object is for the boom to take the force on the line for the clew to lay next to the boom with the maximum tenstion. Getting the new clew to lay down flat can be a hassle in a single line system and easing off both the mainsheet and vang helps out a lot when setting a reef. You did not mention what size of boat/reefing line you have. The rigging specs for my boat (C34) call out for half inch dacron. I have gone down to 3/8 inch spectra on my reef #2 line to save weight. The strength/stretch properties exceed the original Sta-set that came from the factory. Make sure your line is properly sized for any clutch or cleat.

The second photo illustrates the problem with single line reefing. The reefing line suffers friction going through the new cringle, making for more tension on the tack than the clew. Unfortunately, most of the force is on the clew. I rigged a Harken Carbo Block to reduce that friction, but unfortunately, now have a point of chaffe in my system. The solution for that is to cut new exits on the bottom side of my boom, but the extra slots will weaken the boom just where you want it to be strong. One solution begets a new problem…

http://im1.shutterfly.com/media/47a0...D550/ry%3D400/

http://im1.shutterfly.com/media/47a1...D720/ry%3D480/<O:p


svHyLyte 02-11-2011 07:24 AM

In the lower photo, the forward angle forced on the reefing line by the bull's eye block on the mast immediately below the boom pulls the turning block connected to the cringle strap at the luff forward, causing the line to run over the forward edge of the exit slot on the top of the boom. This arrangement introduces a lot of unnecessary friction to the system and will cause the line to fail at the slot in the boom due to chafe in any extended blow. Eliminating the bull's eye block below the boom will eliminate these problems and create a fairer lead to what I assume is a turning block at the mast base. Single line reefing sustems are great in theory, in practice, not so much.

FWIW...

sailingdog 02-11-2011 08:01 AM

I'm not a big fan of single line reefing systems as a general rule, but if he wants to keep the single line system, the lead to the cringle would be much better if he ran the line through the cringle using the Goiot blocks. This would eliminate most of the chafe issue caused by that turning block on the dogbone going through the cringle, since the line would lead higher to where the cringle actually is,rather than three or four inches below it, as required by the dogbone and turning block. Also, it would be less weight aloft.

Finally, if the Goiot block fails, the line is still holding the cringle down. If the dogbone or turning block fail, the sail goes free.


Quote:

Originally Posted by svHyLyte (Post 696865)
In the lower photo, the forward angle forced on the reefing line by the bull's eye block on the mast immediately below the boom pulls the turning block connected to the cringle strap at the luff forward, causing the line to run over the forward edge of the exit slot on the top of the boom. This arrangement introduces a lot of unnecessary friction to the system and will cause the line to fail at the slot in the boom due to chafe in any extended blow. Eliminating the bull's eye block below the boom will eliminate these problems and create a fairer lead to what I assume is a turning block at the mast base. Single line reefing sustems are great in theory, in practice, not so much.

FWIW...


zz4gta 02-11-2011 09:41 AM

George, lash the ti-lite block to the ring on the starboard side of the boat. Will raise the block up higher than the original design and hopefully change the lead angle enough to stop the chafe.

I'm surprised you can use one of those blocks. Seems like a light piece of hardware for the task.

l_lym 02-11-2011 01:54 PM

The Goiot block looks like a perfect solution. In a quick look I didn't see anyone distibuting it in the US. Where did you find them?

PeterSailer 02-11-2011 03:57 PM

Quote:

Finally, if the Goiot block fails, the line is still holding the cringle down. If the dogbone or turning block fail, the sail goes free
Fail safe...I like it :cool:


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