Intermediate Shrouds

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hennypenny

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Hi all,

I am currently moving my boat slowly from Chichester to Suffolk, made it to Eastbourne this weekend, pretty hairy through the Looe Channel on Saturday.

On Sunday we had the opportunity for the first time to have both sails up. The boat is a Bavaria 31 with a fractional 19/20th rig with 2 sets of swept back spreaders.
I have a question about the rigging: How tight should the intermediate shrouds be? For the avoidance of doubt I am talking about D2 and D3 in the diagram on page 10 of the Selden Hints and Tips document. When sailing the leeward intermediate shrouds were completely loose and were completely limp, this seemed slightly worrying but everything else seemed fine, the windward side appeared tight. Should I tighten them and what do they actually do?

I only bought the boat recently and the old owner had the mast unstopped for transportation. I am not sure to what length they went to retune the rig.
Any pointers would be very gratefully received!

Thanks all!
 
The safest solution would be to ask a rigger to take a look, and to adjust as required. He may also spot any potential concerns which ought to be taken care of. Many rig failures are caused because DIY boatowners tend not to tension the rigging sufficiently.
 
After the mast goes in I adjust it laterally and for rake, the intermediates are set bar tight using last years marks, the spreader angles are checked with a plywood template, then we go out in about 15 kts and head to windward, take up all the slack on the lee side, tack and put the same number of turns on the other side. Come back in and secure the bottle screws, I use cable ties cos the mast comes down again in six months. The last boat was a bit more difficult because it had discontinuous rigging with adjustment up at the first spreaders but the mast shape was easier to tune. On 30' plus lowers are always tighter than you might expect, a 14 stone man pulling them aft at shoulder height should not be able to move them. I used to race with a rigger among the crew, he would be apalled at this oversimplification.
Of course this is the simple way, if you want real speed it becomes more complicated.
 
My hanse 311 has a similar rig & the uppers are set at 24-26% with a loos guage. To give you an idea of that it is about as tight as i can get them with large well fitting spanners without damaging the screws
The mids are then adjusted to give a pre bend of 50mm
the lowers are then adjusted much less so that when I tighten the 32:1 backstay i can get a 150mm mast bend to flatten the sail before reefing (discussed & agreed with the sailmaker )
I will not tell you the loos readings, they are set & recorded by me to suit my sails & give me max performance up wind
I can tell you, however, that the lowers are quite slack as I need to get the bend in the right places.
At no time do I ever see loose shrouds when sailing up wind in any strength of wind
It has taken me some time to get my readings right, but we can get a very consistent 6.5 kts upwind speed through the water (when my son helms, that is, not me!!!!) in 15 kts wind & point as high as the opposition, which is not bad for a 31 ft cruising boat
If the mids & lowers are too slack the mast bends too easily & I get less forestay tension. Too tight & I cannot get sufficient pre bend. So it is all matched with mast rake- My forestay length is fixed so i have now had 4 different lengths to get it right
 
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Boats do differ however, My masthead rigged Jeanneau has both fore and aft 10mm lowers, which require as much tension as the cap shrouds, whilst the intermediates are 8mm and have much less tension in both absolute and percentage terms. I think the OP needs to consult a rigger as the intermediates going slack may indicate that the mast is taking on an undesirable degree of sideways bend when sailing.
 
Thanks all- I will try and track down a rigger
Does anyone have any recommendations for one around Eastbourne preferably to attend before next week?
 
I have a Bavaria 38, much the same design of rig as the 31, albeit larger. I had my rigging checked over recently and in discussions with the rigger about tensions he said that when sailing to windward with a “decent wind” that you could expect to see the leeward shrouds loose. So, whilst I would get a rigger to check things over, I wouldn’t be overly worried about some play in the leeward shrouds.
 
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