Standing Rigging Tension

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T

Tim

In preparation for replacing the standing rigging I used a Loos tensionometer to measure the tension on all the wire rope except for the headstay which is covered with the reefing foil. Does anyone know of a way to measure the tension with the foil installed? It appears that the whole rig has to come down to remove the foil thus eliminating the ability to measure the tension. Tim
 
G

Gerry

Rig tension

I have the same problem you have encountered due to the roller furling. What I do is just adjust the back stays tension and set it for the rake I want. Its the transference of force principal. If you end up with too much rake at the proper tension relax the backstays and adjust the forstay length. Its not the perfect way to do it but it has worked well for me.
 
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Alan

NoNoNo

You CANNOT set the rake on a mast any other way than adjusting the headstay length!!! Rake is set with no backstay tension. Hang a weight from the main halyard at the boom and measure how far back from the back end of the mast it falls. That’s your rake setting. To increase rake, lengthen the forestay and vise versa. You have no need for the tension in the forestay even if you could read it. If you take the rig down and want the same rake setting in the spring, simply do the test with the main halyard again and make the adjustments that give you that same measurement.
 
B

Bayard Gross

Since you should be replacing the forestay too,

You say you are in preparation for replacing the standing rigging, hence, I assume this means the forestay as well as the shrouds. I also assume you are going to be taking your mast down, as you probably do not have access to a sky hook and your wife calling you an angle does not mean you are dead and can fly. Hence, you will remove the furler from the old forestay so it can be placed around the new forestay. What you are probably trying to do is raise the mast up again with the new standing rigging and the forestay on as well to save yard time, a worthy decision. However, this causes problems with getting forestay tension readings. Nevertheless, there is a possible solution. Most furlers can separate the drum from the extrusion, usually with no more difficulty than loosening some screws. After the extrusion is separated from the drum, it can be moved upward along the forestay, using a halyard tied to its bottom to a point where the top of the extrusion butts up against the upper forestay toggle. This may allow enough forestay wire to appear to permit affixing a Loos tension gauge for a reading. If it does not, then the extrusion could possibly be cut down to only enough length to support the luff of the jib. In this way, the extrusion may be short enough to be lifted to allow sufficient forestay wire to show for a Loos reading. The issue of halyard wrap is considered only if you have a Pro Furl furler with its Wrap Stop feature or are using a wire pennant on the jib to get the swivel closer to where the halyard exits from the mast. Further, I think a shorter extrusion would help alleviate halyard wrap, as there is that much less turning extrusion to grab the halyard and wrap the halyard around itself. I employ this method with getting Loos gauge tension on my forestay that has a furler on it. However, I have a CDI unit that has an internal halyard that eliminates any halyard wrap problems. Moreover, as using the halyard to adjust jib luff tension on a furler is limited as the sail is held in place in the furler’s sail groove, the internal halyard has only the vice of difficulty in setting up the jib. Further, the CDI extrusion is a single piece with zero joints to separate which means I can still effectively use my backstay adjuster which loosens the forestay to power up the jib, a terrific feature of CDI units.
 
L

Lauraine

Question for Alan: If one is only supposed to

adjust rake using the forestay, what are backstay adjusters supposed to be used for?? Curious minds want to know...:)
 
D

Dave Mauney

From Brion Toss

The following is from the Brion Toss site "SparTalk" that seemed pertainent to this discussion. "The bad news is that you cannot measure the tension with a gauge (with the furler on). The good news is that you don't have to. The dockside tune for all wires is meant to be a preliminary process, with follow-up underway, during which you look and feel your way towards perfect tune. In the case of the shrouds, you check mast bend and slack to leeward. In the case of the jibstay you look for luff sag, or lack thereof. At dockside you adjust jibstay and backstay such that you have, for instance, 15% on the backstay and proper mast bend/rake. On most boats, given relative backstay angle, this will put something more than the sample 15% on the jibstay. Might be perfect, might not; you have to examine sag under way." He also mentions in another posting that any further adjustment needed in forstay sag can be done with the backstay only. I found his tuning video very good. See link. Good Winds, Dave s/v DAMWEGAS
 
A

Alan

Answer to your question

Rake is the horizontal distance aft that the masthead is with respect to the vertical at the gooseneck. It is a static measurment. Sure you can pull the masthead back further with your backstay but that will not change the initial setting which is the rake. The backstay is there to bend the mast so that you can flatten the main as needed. Rake can only be set with no load on the mast (unbent). The only control for the aft position of the masthead is the length of the headstay. Applying shroud tenision on swept spreaders and backstay will move the masthead, but that is not how rake is measured. After the rake is set the rig can then be tensioned to whatever the specs call for. I hope that I have answered your question.
 
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