Inadequate Design of Furling Systems

[Spirit (of Glenans)]

I have recently been involved in an incident-plagued and protracted(two weeks instead of five days) delivery from Greystones, Ireland to Bayona, Spain, during which the jib furling line chafed through twice, forcing stops first in Newlyn, then in Concarneau. On both occasions the jib had been heavily reefed and left us in dangerous situations when it unfurled to its full size, the second time in 30kt+ winds and heavy swell, leading to to an unintended gybe which detached one of the mainsheet blocks on the boom. There followed a second unintended gybe back to the other side, this time without the restraint of the mainsheet, and with considerable force. We were extermely fortunate not to have been dismasted.
I won't mention the make of the furling gear, or the name of the installers, but suffice it to say, the problem was caused by the s/s cage not being bolted up tightly enough, allowing the line to ride up and chafe on the edge of the drum. We had attributed the failure to other causes and only found this out in Concarneau when we engaged the services of the excellent riggers from Cornauaille Greement.
Having reflected on what had happened, I came to the realisation that there is a serious lack in the design of these things; the fact that they don't fail "safe", but fail"dangerous", giving full sail when it is least required. My question is; why is there not some kind of ratchet/sprung pin mechanism to lock the spool in the required position so that is not relying on the furling line to stop it unrolling? Said locking mechanism could be unlocked by a second line to the furler.

 

[pvb]

If it had been installed properly, presumably the line wouldn't have chafed and you'd have avoided all the drama. You can't really blame the design of the gear if it's badly installed.

 

[scruff]

Adding a ratchet would increase friction and be a bugger to keep lubricated due to being dunked all the time.

It sounds like the first line to part was unfortunate but you failing to investigate / work out what caused the chafe in the first line caused the second line to fail in the same way (apologies for being blunt). If something fails on the boat you really need to ascertain why if failed, then rectify to stop it happening again.

That said, a locking drum could be a gap in the market - you could patent the idea, design a better furler and make a fortune...

 

[Kukri]

I am in the market for a furler for a biggish boat, over the winter, and the same thought has struck me - the whole set up "fails dangerous", and is dependent on a single line not chafing through.

My late father used to say that Thomas White Ratsey called the Wykeham Martin jib furling gear - the first really sucessful roller gear - "the sailmaker's friend" because so many jibs, left rolled with the boat on moorings, unrolled and self destructed when the line chafed through. That was in the 1930's.

Ratchet gears are very well understood - every winch has a couple inside it - and does not seem hard for a manufacturer to incorporate one with a pawl that can be held off by a second line to unroll. I don't think waterproofing it would be that hard.

 

[Spirit (of Glenans)]

If it had been installed properly, presumably the line wouldn't have chafed and you'd have avoided all the drama. You can't really blame the design of the gear if it's badly installed.

True, but the bad installation was why it happened. The ability to lock off the drum would prevent dramatic situations developing in the event, and would allow the tension on the line to be relaxed, thereby lessening the likelihood of it chafing. Being on the foredeck on a F7-8 makes you think of ways to avoid being there!

 

[Spirit (of Glenans)]

Adding a ratchet would increase friction and be a bugger to keep lubricated due to being dunked all the time.

It sounds like the first line to part was unfortunate but you failing to investigate / work out what caused the chafe in the first line caused the second line to fail in the same way (apologies for being blunt). If something fails on the boat you really need to ascertain why if failed, then rectify to stop it happening again.

That said, a locking drum could be a gap in the market - you could patent the idea, design a better furler and make a fortune...

My idea is that the locking mechanism should be held "open" while furling/unfurling, and only allowed to spring into place when the operation is finished. Modern materials would be less likely to need lubrication, but adequate maintenance of all systems is a must on boats.
The boat was only a year old. When the line broke off Arklow we just replaced it without further examination. It was only when it broke off the Scillies and we had to head for Newlyn for more rope, Dyneema this time, that the skipper informed us that it had also broken last year, soon after the boat was first put into commission. It was then that we started to examine it, and wrongly blamed the positioning of the forward stanchion block for the chafe!
I'm certainly going to take some measurements off my own furler and do some drawing......

 

[GHA]

Worry about the furling line parting was one of the reasons I went over to dyneema as a furling line, very chafe resistant and will still be very strong even when chafed most of the way through.

Not easy to think of some ratchet mechanism which wouldn't double the cost and jam often.

 

[Biggles Wader]

If it had been installed properly, presumably the line wouldn't have chafed and you'd have avoided all the drama. You can't really blame the design of the gear if it's badly installed.

Safety is not about blame either of the design or the installation but about how to improve things and build in resiliance. Having something over and above the usual single bit of quite thin rope to prevent an unplanned unravelling of the genoa has to be a good thing. I think the OP is right.

 

[Kukri]

The Wykeham Martin roller furling gear, which incidentally you can still buy, used steel ball bearings, and, by virtue of its position commonly being on a bowsprit, led a harder life than today's roller reefing systems, but I can't think of a single case of the bearings rusting, so I think that it should not be too hard to build in a ratchet that is effectively waterproofed.

 

[Deleted member 36384]

A ratchet would be a terrible idea, off the top of my head: band brakes, centrifugal brake, pin lock, cam lock could all easily be made to be in the locked position normally and held open remotely.

However, anything is capable of jamming and being in the position where the sail has to be reefed but the fail safe brake won't release is equally a risk that needs to be considered. At the end of the day, proper installation and maintenance should not cause frayed rope.

Some people have an opinion that only hanked on sails should be used when sailing further afield. Is this really a problem though, perhaps not, which might be why the additional complication of fitting a fail safe brake is not found on roller reefing gear.

https://www.riggingdoctor.com/life-aboard/2017/8/27/dangers-of-roller-furling-in-ocean-sailing

 

[Kukri]

A ratchet would be a terrible idea, off the top of my head: band brakes, centrifugal brake, pin lock, cam lock could all easily be made to be in the locked position normally and held open remotely.

However, anything is capable of jamming and being in the position where the sail has to be reefed but the fail safe brake won't release is equally a risk that needs to be considered. At the end of the day, proper installation and maintenance should not cause frayed rope.

Some people have an opinion that only hanked on sails should be used when sailing further afield. Is this really a problem though, perhaps not, which might be why the additional complication of fitting a fail safe brake is not found on roller reefing gear.

https://www.riggingdoctor.com/life-aboard/2017/8/27/dangers-of-roller-furling-in-ocean-sailing

I recall that David Scott Cowper was (and maybe is - I haven't spoken to him since he moved back to Newcastle) of that persuasion, when he made his two nonstop circumnavigations in "Ocean Bound".

One can get along quite well with hanked sails, using the old trick of having the next sail down hanked on under the sail in use and bagged with the bag secured.

 

[lw395]

You can lock a Harken roller with a simple pin or even a padlock.
Tens of thousand of yachts go through many seasons without having a problem chafing the furling line.
The statistics make it unlikely adding complication will be an improvement.
Perhpas the OP's problem is really about setting off into strong weather without adequate checking of the gear or a shakedown passage?
Maybe in 35knots, the storm jib should be in use, instead of knackering the client's roller genoa?

 

[pvb]

Safety is not about blame either of the design or the installation but about how to improve things and build in resiliance. Having something over and above the usual single bit of quite thin rope to prevent an unplanned unravelling of the genoa has to be a good thing. I think the OP is right.

But there's no real issue of safety with jib furling systems, unless they're not installed properly. Trying to engineer in solutions to cater for incorrect installation isn't the way to go at all.

 

[dom]

I won't mention the make of the furling gear, or the name of the installers, but suffice it to say, the problem was caused by the s/s cage not being bolted up tightly enough, allowing the line to ride up and chafe on the edge of the drum.............. Having reflected on what had happened, I came to the realisation that there is a serious lack in the design of these things.....

Understand you don't want to dob anyone in, but I find it very hard to think about this in the abstract given that there are several distinct drum designs out there, each handling chafe problems in its own unique way. Moreover, it would be useful to know exactly what the installation error was; was it a small slip-up, or a grave mistake?

 

[dunedin]

Safety is not about blame either of the design or the installation but about how to improve things and build in resiliance. Having something over and above the usual single bit of quite thin rope to prevent an unplanned unravelling of the genoa has to be a good thing. I think the OP is right.

I agree. It is poor design that something that can be so critical doesn’t fail safe, but if fails unrolls.

In one gale in April I had to climb on board two boats close to us whose jib furling lines had failed - one, which was an otherwise immaculate and well maintained boat, ripped its laminate jib before I could find a lull that allowed me to get on board across the bow past the flogging sail.
Coming across the North Sea this year with jib reefed our cruising dyneema chafed through the outer cover, unnoticed till back in harbour.
And a couple of years back a man nearly died from a boat which left the marina beside us. As I understand it genoa reefing line parted on the charter boat in 30+ knots, whereupon the genoa unfurled completely, making the boat uncontrollable. With only a couple on board the skipper went onto the foredeck alone to try to drop the sail but the force of wind in the flogging sail knocked him overboard. Fortunately a mayday call and having a lifeboat station nearby (rare in Scotland) saved the skipper.

So certainly a good idea to look at a fail safe design. Saying this would be inefficient / cause friction / not work is classic negative (non) thinking. The challenge is to design an effective fail safe. If car designers had such negative thinking then most of our safety improvements to cars (ABS, traction control, seat belts, crumple zones ......) wouldn’t be in every car today.

 

[lw395]

I agree. It is poor design that something that can be so critical doesn’t fail safe, but if fails unrolls.
....

I look forwards to seeing proposals for simple fail safe systems, with proper analysis of how the safety systems are more reliable than a properly installed piece of string.
You can systems which fail with the furling locked, such as Harken's electric models. It's only another 8 grand or so, and we all have opinions on the reliability of electric stuff on boats.

In the meantime, there is a backlog of 40 years worth of string-on-drum furlers which we will all encounter, maybe we need to check for chafe more often?

 

[Deleted member 36384]

Perhaps the fail safe methodology is to unroll fully, that way the sail can be taken down if the furling mechanism fails.

 

[Tranona]

In the meantime, there is a backlog of 40 years worth of string-on-drum furlers which we will all encounter, maybe we need to check for chafe more often?

This does not seem to come up as a systemic issue - that is firstly the number of failures is probably extremely small and the consequences manageable.

Pretty sure the clever manufacturers would have a found a solution if indeed the problem was "real".

In this case it was poor installation that caused the problem rather than a defect in the design or manufacture which suggests if it was properly installed there would not have been a problem!

 

[rotrax]

As to furling jibs coming undone on the mooring, I find a couple of turns of good 8mm braid put on after furling as belt and braces works for me.

Simples..................

 

[PuffTheMagicDragon]

I think that the answer is in the title of this thread. The system is for "FURLING" and not 'REEFING". I know that many seem to consider the two terms as being interchangeable but they are not. If the wind is likely to pipe up to the level where the large Genoa becomes too much, I furl the sail, rig up the second forestay (with a Highfield lever) and hank on the storm jib.
Having said that, my present boat came with a Goiot furler and I immediately noticed that the guide for the line looked wrong. It took me all of ten minutes to realign it with the first block (re-positioned upwards) on the first stanchion so that the lead was fair. No trouble since then.