[70521]
Well-Known Member
I fully understand all of the forces. I still don't understand why my puny 6mm line, of unknown type or age, handles it with ease? Yes, I was out in a F7 this summer and no it did not snap like a bit of wet string.
Making up a tapered furling line
- Thread starter stranded
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thinwater
Well-Known Member
If you furl up wind in a blow the load can be considerable. But there is seldom a good reason to do that. Virtually never, and poor planning is normally involved.
Off the wind you can blanket the jib behind the main, reducing the load to nearly zero even in a gale. However, if you furl like that the bundle will be loose and probably will unwind in the wind. So you keep enough back tension on the sheet to get a nice tight roll. How much? Depends on the size of the sail, but probably about 5% of the upwind sheet tension is enough. Something like that. It also depends on the sail cloth and furler design. On a mid-size boat you should have to lean into it and use both hands (to offset the back tension), but you won't need a winch (other than a single wrap as a ratchet, so that it does not get away from you and so you can shift your hands more easily). If you do use a winch, it should be very light pressure, as you ease the sheet. There's no shame in using a winch, just make sure you are not cranking it hard against something that is jammed!
stranded
Well-Known Member
Hmmm… stretching your improbable but not impossible scenario to 35kts gives me 1500kg+ sheet load, which without knowing what portion of that would be transferred to the furling line would take decored 10mm braid into at least squeaky bum territory.
Shouldn’t happen but has when we got mugged from behind by a rapid increase in wind strength from 20kts to 35-40kts running west in Malaga bay - autohelm couldn’t cope, I couldn’t leave the wheel for a second, and the sea got up so quickly and so steep that I dare not turn into it to loose sail so had a buttock clenching hour running for shelter at the very edge of control at speeds that made a mockery of hull speed calculations. Rookie mistake, but I fear I still have plenty of those in me!
So maybe back to a dyneema solution - I’ll talk to the riggers!
dunedin
Well-Known Member
Crossing the (wide part of the) North Sea we got hit but unforecast 30-37 knots on the nose for 12 hours or so off the bottom of Norway. We definitely needed to reef the jib in this, and it took a lot of strain as we bashed upwind with the jib winched to as hard as we could turn it.
When we arrived I discovered that the outer of the cruising dyneema reefing line had chafed in that 12 hours (if hadn’t in the 4 years prior or since). I would not want to have any doubt about the strength of a genoa reefing line in 40+ knots (unless a boat with a proven inner staysail used in these conditions - but an inefficient nuisance for most coastal cruisers for the rest of the time)
When we arrived I discovered that the outer of the cruising dyneema reefing line had chafed in that 12 hours (if hadn’t in the 4 years prior or since). I would not want to have any doubt about the strength of a genoa reefing line in 40+ knots (unless a boat with a proven inner staysail used in these conditions - but an inefficient nuisance for most coastal cruisers for the rest of the time)
Iliade
Well-Known Member
if you strip the inner from the furling line the whole will end up as a narrower coil on the drum. This will increase the load on the line when in use.
Hence if stripping the core perhaps one should also run a few turns of webbing around the drum to build up the coil diameter, thereby reducing the reefing loads?
Hence if stripping the core perhaps one should also run a few turns of webbing around the drum to build up the coil diameter, thereby reducing the reefing loads?
thinwater
Well-Known Member
Normally the reason to strip core is because there is not enough room on the drum. Fortunately, the peak furling line load is when you first start furling, and the drum is slam full at that point. Toward the end it gets much easier, because there is less sail out.
If the drum were oversized you would be correct. For example, using a small jib on a furler with capacity for a large genoa. The solution is simply to use the same furling line, and load the sail in the foil when the drum is full.
Wing Mark
Well-Known Member
Also consider if the rope is more highly loaded, it will stretch in gusts, which will, in extreme cases, make the jib fuller, and also perhaps lead to more chafe as everything moves more as you go over every wave etc?
stranded
Well-Known Member
While so many very knowledgable people are reading this, can I drift my own thread slightly and ask, if experience reveals that one really should not have used that under strength furling line and one finds oneself with a snapped line and heading towards a lee shore in 40kts, is there ANYTHING one can do? I am assuming getting a big sail down in such circumstances is simply not going to be possible on any point of sail, at least not effectively single handed? Let go the sheets and let the sail fly (until the rig comes down?) Slash the sail and hope it tears along the luff and eventually detaches itself? Deploy the (masthead) removable inner forestay, release the main forestay and hope the whole sail and foil sort of drop off the end. Or pray quietly into your rum while reviewing the wisdom of ignoring the pre buying advice not to get a bigger boat than you can handle when the sh1t flies!
mikegunn
Well-Known Member
You are right in theory but in practice I've not noticed any difference. I've always had around ten turns left on a drum when the sail is fully furled as I sometimes continue and put ten turns of the sheets around the sail. Reduces chance of it unfurling in a storm. I also tie off the drum to a convenient hard point on the deck for the same reason. As I've mentioned previously the decored line lies flat on the drum precluding any chance of the turns collapsing.
Mike
Gwylan
Well-Known Member
Contact Joe at or via OutdoorXscape for advice or making one up for you.
Did similar for us a few years ago.
thinwater
Well-Known Member
Yes, I have watched for that. The amount of movement is very small, much less than 1/8-inch in the most severe conditions. The problem was where the line rubbed on the drum shroud, and slight repositioning of guides and the drum solved it.
But low stretch is a good argument in favor of Dyneema. Of course, that does NOT mean the line cannot be tapered, only that you would most likely do it a different way, by stripping the cover instead of the core. Just as easy. If you don't want to buy a new polyester-covered Dyneema line, replace the existing core with Amsteel, and then keep only the best part of the cover. Also easy.
Iliade
Well-Known Member
I had the foil detach from the drum on a Centaur in much these conditions within Poole harbour. It was about the limit of what I could hand furl by twisting the foil after letting the sheets fly. With a bigger sail I figure I'd have had to use an adjustable spanner, water pump pliers or pipe wrench on the foil. If the foil is still attached to the drum then it should be fairly easy to do, so long as the sea is not too boisterous.
stranded
Well-Known Member
Ah, that’s interesting, hadn’t thought of that during my catastrophising. With 60m2 of sail up there and cracking sheets it would be a scary place to be, but at least you would die trying to do something. Have to figure how to stop it unfurling again between turns - could be heartbreaking if whatever tool slipped when you were 7/8ths done. I’ll have a look to see how it could work - then I can take a chance with a lighter furling line!
Wing Mark
Well-Known Member
A new lighter furling line might be better than an old frayed heavy one?
stranded
Well-Known Member
It imagine it would be, but the test isn’t ‘better’ but ‘good enough’.
thinwater
Well-Known Member
It's a foil. You pull it down. This is one reason to keep the tape lubed and the foil clean. Yes, I have had furler bearings fail and that is what you do.
There is a level of poor planning that is unrecoverable. If you are skirting a lee shore in 40 knots, I'm sure there are a few things that can go wrong.
I don't think anyone suggested an under strength line. If the sail is furled the load on the line is very light. If you are using it as a roller furler use a sturdy line.
dunedin
Well-Known Member
Very relevant point.
I believe this happened to a charter boat near us a couple of years back. Two people on board and the furling rope broke, and all hell let loose with a flogging sail in just 30 knots. Large and fit skipper went forward to try to drop the sail, but got hit by the flogging sheets and knocked over board. Fortunately very close to a lifeboat station and crew called Mayday and doubly fortunate the MOB was quickly rescued (mid summer so presumably water not as cold as usual). Boat towed back by lifeboat. A very lucky escape.
stranded
Well-Known Member
I’m sorry, I wasn’t meaning to be facetious, it was a genuine question to inform to what extent I trade ease of use against certainty the line doesn’t break. I thought most people use their furlers as reefers too - maybe not.
thinwater
Well-Known Member
I know you were not. The first time I had a furler failure it took me a long moment to remember I could still use it as a foil, as racers do.
The furler line need only be about 1/4 the strength of the sheet, based on measure load. After that, it is all about watching for chafe, which is easy to miss unless you walk the deck when driving hard reefed.
The furler line need only be about 1/4 the strength of the sheet, based on measure load. After that, it is all about watching for chafe, which is easy to miss unless you walk the deck when driving hard reefed.
Neeves
Well-Known Member
I believe your thought is correct - most people use their furler as a device to reef the headsail - other wise you have a head sail that can only be used, sensibly, upto 20/25 knots and then needs to be furled completely - leaving you with no headsail at all. Unless of course you are monied and have an inner forestay or 2 furlers.
Trying to remove a large unfurled headsail from a foil - is simply a non starter. The sail will be flogging, the friction between sail and foil will lock the sail solid. If you are trying to do this it is because the wind is up and seas have built. If you get the sail off the foil exactly how are you meant to handle this monster on the deck? Sometimes I think the suggestions are made by people who have never been 'out at sea' and the suggesting are impossible and dangerous.
Most people are sailing as a cruising couple or family not as a troupe of gorillas. If the task cannot be completed largely single handed - the task cannot be completed.
Like many devices on the family yacht a furler is a god send and makes family sailing possible to all of us - this is until the furler, does not furl. then its a disaster waiting to happen (and the family will never come sailing with you again). Check your furler, and the other critical bits of kit, before you get into panic mode. If you furl your headsail under tension (full of wind) it will furl tightly and you will find that if you do not have extra turns and you cannot furl completely. You need extra turns on the drum - which also allows you to 'furl' the sheets round the sail better securing the sail (as mentioned on an earlier post).
I see maybe 2-3 headsails flogged to death and torn to ribbons for headsails that have slowly, or rapidly, unfurled due to inattention in a stronger wind event. You lose money in a destroyed sail and upset the neighbours from the noise of the flogging sail (at 3am).
Play with your furler and line on a calm day in the marina, on the swing mooring. Add a few extra turns on the drum, make sure the drum loads evenly (or the furling line can jamb in the 'cage').
Jonathan
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