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Post by gerald on Jul 1, 2020 22:59:24 GMT
Hi All,
I have a 2018 SO 440. Vessel has in-mast furling main sail.
I put the main sail back on last week and I’m not sure how much tension is “enough” to be putting on the main halyard?
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Post by Zanshin on Jul 2, 2020 5:17:17 GMT
The tension when furling should be enough to make pulling in the sail noticeably more difficult, but the amount of tension is less important than having the correct angle on the boom when furling. If that angle is wrong either the top or bottom of the sail is going to be loose and regardless of how much back tension you have while furling that part will be loose.
I usually will wrap my outhaul around a winch once or even twice and keep light back pressure on that while pulling in the main.
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Post by panoramix on Jul 2, 2020 7:30:59 GMT
The tension on the main halyard should be such that there is no slack anymore in the front luff. After that you can hoist the mainsail another inch.
If after some days of sailing you get slack in the front luff, repeat the procedure.
It is similar to the tension on your genoa. If you put too much load on the bearings these are stressed and furling will be more difficult.
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Post by alenka on Jul 2, 2020 7:36:49 GMT
Hi Gerald,
Somewhere on this forum is a very long but informative thread about all aspects of in-mast furling.
I read your post a little differently to Zanshin. You are asking about the 'Halyard' tension controlling the luff of the sail not the tension on the out-haul and furling lines??
Too much tension on the halyard will make life difficult just as too little will cause creasing and problems also.
I would suggest you think of it as you would when hauling up a normal sail, Just enough to get rid of any vertical or horizontal creases - but no more. If the sail furls and unfurls easily, following the other rules of in-mast management, then lock it off on the clutch and make sure that no one messes with it. Twice I have had the clutch released in error with the sail furled and it took some time to get it out of the mast to reset the tension.
Zanshin is spot on about boom angle when unfurling and keeping a level of tension on the outhaul when furling to keep the sail smooth as it enter the mast.
I also find it is a good idea on our rig to tighten up on the furling line just prior to unfurling. It always seems to me that it goes a little slack over time.
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Post by Charlie-Bravo on Jul 2, 2020 7:58:09 GMT
Just one thing to add, furling mains tend to stretch their luff, as most owners seem to hoist the sail at the beginning of the season , tension it well, and there it is until the end of the season, sometimes although the sail looks fine, they can have stretched so far that luff tension can no longer be had. This does effect some furling mechs more than others, ours had a lot of stretched luff and I had to shorten the sail by an inch to get the wrinkles out of the luff and allow a smooth furling.
Just might be worth checking your luff v available room for it in the mast if you can't lose all wrinkles, and as a general guide, once you can lose all the wrinkles it's about there.
CB
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Post by gerald on Jul 2, 2020 13:35:46 GMT
Hi Gerald, Somewhere on this forum is a very long but informative thread about all aspects of in-mast furling. I read your post a little differently to Zanshin. You are asking about the 'Halyard' tension controlling the luff of the sail not the tension on the out-haul and furling lines?? Too much tension on the halyard will make life difficult just as too little will cause creasing and problems also. I would suggest you think of it as you would when hauling up a normal sail, Just enough to get rid of any vertical or horizontal creases - but no more. If the sail furls and unfurls easily, following the other rules of in-mast management, then lock it off on the clutch and make sure that no one messes with it. Twice I have had the clutch released in error with the sail furled and it took some time to get it out of the mast to reset the tension. Zanshin is spot on about boom angle when unfurling and keeping a level of tension on the outhaul when furling to keep the sail smooth as it enter the mast. I also find it is a good idea on our rig to tighten up on the furling line just prior to unfurling. It always seems to me that it goes a little slack over time. Correct. I’m concerned because I can’t get the luff completely free of wrinkles maybe one forth down towards the foot. I tensioned the halyard a bit more to try and “fix” this but it seems to have made furling the main just slightly more difficult. Maybe I should back it off slightly? There is a good amount of rake in the mast head - vessel is balanced perfect with less than three degrees of weather helm at most. As Zanshin pointed out we always hold slight tension (slip thru hand type) when furling the main and vis-versa when hauling out. I do however sometimes furl the main while running - or on a beam reach with boom extended out on the lee side. |
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Post by moonshadow on Oct 30, 2020 1:12:58 GMT
I found that my roller furling main needs more halyard tension than I expected. If a bit loose the bottom of the luff tape below the end of the luff groove/feeder will pop out of the a lot when off the wind and will jam when trying to furl.
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Post by alenka on Oct 30, 2020 15:30:45 GMT
i recently came across some information that talked about the correct tension of the foil within the mast also being a key element to a good working system. It suggested that if there is a lot of 'slap' within the mast when the the sail is not installed then the tension probably needs to be increased.
I have never seen any obvious adjustment for foil tension, but then I have never really looked. Being a 1,000 miles away from the boat it will have to wait until next spring for myself.
As anyone else had to adjust foil tension or know how it is done? No doubt each mast system will be slightly different.
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Post by moonshadow on Oct 30, 2020 19:59:37 GMT
On my usspars ( Z-Spars) mast the foil is not under tension. It actually rests on the furling drum.
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Post by saltymetals on Dec 14, 2020 12:50:10 GMT
Gerald, I think the previous replies have probably covered yr question but if the halyard is too slack you will get horizontal folds in the sail. You need to tension just enough to get rid of these. If you tension too much you will then get vertical folds parallel to the mast and near to the luff. Once the correct tension is found i mark the halyard with a coloured pen at the Spinlock so if someone releases it by mistake you immediately know what position you need to re-tension it. I do the same thing and mark my genoa and gennaker halyards. The latter being particularly critical since it is on a top-down furler.
You do not want the luff of the main to get stretched permanently so it is good practice to release the halyard a little to relax the tension if you are not going to use it for a while. This needs to be done BEFORE you furl since otherwise if you relax the tension when fully furled it will only release tension near the head instead of all the way down the luff.
If you get any jamming of the sail in the slot when unfurling there are three things you can do to reduce this possibility 1) not too much mast bend. Approximately half of the chord of the mast should be enough. 2) do not over-tension the halyard 3) move the stopper on the boom back to at least the halfway point along the boom. 1&2 reduce the pressure of the rolled sail against the slot at a point which is about halfway up the mast. Step 3 seems to be the magic since it gives a more horizontal pull on the clew when unfurling. It is of course essential to keep a little tension on the outhaul when you are furling to make sure you get a tight furl. As Zanshin suggested, one turn of the outhaul around the halyard winch should be enough tension while furling.
One final trick is to put one or two cable-ties on the loop at the tack of the main to stop the loop dropping off the hook if you relax the halyard tension excessively. While not vital i always put a few turns of a strong whipping twine around the tack of the main and around the foil. There is a lot of tension at this point when sailing to windward in a strong wind and you can pull the luff rope out of the groove of the foil.
Best of luck
Andrew
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Post by mesteve on Mar 20, 2022 19:03:16 GMT
What is the magic angle for the boom before furling?
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Post by Charlie-Bravo on Mar 20, 2022 19:43:12 GMT
Unfortunately there isn't one, the cut of your sail and the height of clew will mostly determine what boom angle you need, also through into the mix the angle of sail to the wind and it's speed, and sometimes it's easier than others.
As a starter guide, if the foot and leach have about the same tension whilst furling the first third, you won't be far off, but various cuts of sail like different things.
The aim is of course is to avoid any creases as you furl, as these creases increase the diameter of the furled sail, and on some masts can make furling hard work, and doesn't do the longevity of your sail any favours.
If furling the sail is stiff, perhaps requiring a winch, then it is worth seeing how the furling mech behaves without a sail attached, it wants to be free and easy, with virtually no resistance. If the sail is old and stretched , giving a wonderfully powerful light wind main, it can well be a bugger to furl without creases and added snarl ups, I treated ours to a new main .... alarmingly flat to my eyes, but it furls faultlessly.
CB
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Post by NZL50505 on Mar 21, 2022 1:22:23 GMT
What is the magic angle for the boom before furling? I’ve always found that by releasing both the mainsheet and vang the mainsail furls fine. I don’t know what the angle is but the piston in the vang almost certainly pushes the boom up a little bit so the tip is higher than the gooseneck. This seems to work fine for me. I’ve always understood that boom angle is more critical with in-boom furling than in-mast furling but I might be wrong. |
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Post by Charlie-Bravo on Mar 21, 2022 8:54:56 GMT
Your understanding is correct, my last boat had a Sailtainer boom furling set up, with a fully battened main.
Its a bit like rolling up a carpet, if things are not angled quite right the carpet spirals off one end or the other, the same happens with the boom furl, but if the sail spirals forward it can jam up, and spiralling aft causes the luff boltrope to jam.
A lot of mast furling sails are foot cut less than 90 degrees to the luff, allowing the foot to spiral up the mast, if it doesn't spiral up the mast because the boom is too low, the foot hem starts to overlap over its self , increasing the furled diameter ... and possibly jamming up, ..... hence the raising of the boom a little to furl.
most boom furls have a cable at the kicker , so when you tension the topping lift, or release the kicker with a gas ram to push the boom up, the boom stops in the right place .... well that's the theory, and after a year of swearing at the boom furl, eventually shortened the cable 3/4", and that sorted it out.
good bits of boom furling, you can have a great main sail, and if anything drastic happens when furling .. you can resort to dropping it like a traditional sail, unlike a furling mast where not being able to reef in a blow can be entertaining !!! but both furling set ups are so much easier than slabs when sailing short of crew.
The only downside to my mast furling set up is the choice of sail shape , ...... but it still sails well, and I am still learning what the new sail likes in the way of boom height and foot loose v tight to tease a shape out of it, it's all a compromise.
CB
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