Furling Mainsail or Not ?

[robert sailor]

Originally Posted by Sailor Doug

If you think air battens are cool you should not have a in mast roller furling. Keep it simple and low risk or go to standard full batten main.


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Just because I think an idea is cool doesn't mean I want to own it, I mean I think cats are cool but I'm not interested in owning one.

[SailSC]

Just my two cents worth. I have done about a dozen bareboat charters and have had two boats with in mast furling. On each of these boats the furling line came off of the worm gear in the mast and caused an override that jammed up into the tiny slit in the mast and we played heck picking it out and then rethreading the line. It seems to me that extra care must be taken to make sure everything is set just right before furling or unfurling to avoid an override. Based on this limited experience I would not choose to have this system on my own boat.


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[Dockhead]

Originally Posted by SailSC

Just my two cents worth. I have done about a dozen bareboat charters and have had two boats with in mast furling. On each of these boats the furling line came off of the worm gear in the mast and caused an override that jammed up into the tiny slit in the mast and we played heck picking it out and then rethreading the line. It seems to me that extra care must be taken to make sure everything is set just right before furling or unfurling to avoid an override. Based on this limited experience I would not choose to have this system on my own boat.

In-mast furling is surely not a good system for bareboat charter boats, or for the climes such boats are chartered in.

The problem you experienced is caused by not keeping tension on the other end of the furling line. I've never had that particular problem, but would surely be to be expected with charterers.

The furling line is a weak point of these designs. It's pretty well executed with the Selden system which I have and can't get jammed in the mast (it has a removable shield around it and winch handle override), but the problem is you need three hands to furl -- one hand (with a winch) to keep tension on the outhaul, one hand to haul in one end of the furling line, and a third hand, which is absolutely necessary, to keep tension on the other end of the furling line, so it grips the drum. I single hand a fair amount and have some workarounds, but they are awkward.

For this reason, if I have in-mast furling on my next boat (and I probably will if I stay up in these latitudes), it will be the kind with the electric drive built into the mast.

[Island Time O25]

Can any CF engineers explain this to me? Everyone is saying how battenless furling main is inferior to standard battened one. Yet somehow all the sailing books say that the genoa is the driving force of the two sails and the main usually playing the 2nd fiddle. Why wouldn't 2nd genoa/jib installed as the furling main be just as "driving" as its bow counterpart?

Let's take this question further. Let's assume outside furling main with no boom and a foot as large as the bow gennie. Now we have two gennies so to speak. Wouldn't that mean 2X the driving force of one gennie? And if not - why not?

[scherzoja]

Just a quick observation about a furling main is that it only has one clew, so it better be well build. Slab reefing mains have one clew for each reef and if the unreefed clew blows out, take in a reef and get on with life. If the only clew blows out, whatchya gonna do now with the sail flapping like crazy?

I have a Hood Stoway in-mast furler (came with the boat when I bought about 4 years ago, what can i do about it?). It appears to be as old as the boat (30+ years). It seems to do well, hasn't jammed yet, no lines to override because it has a geared mechanism at the mast, which means I go to the mast and use a winch handle to crank it while easing the outhaul to furl/reduce sail area; it's not all that difficult. Only problem that has not occurred yet is what to do when the clew blows out or if I can't furl the sail. If the sail is already all the way out, just lower it like any other sail.

I know the furler main might not be as good of a performer as a normal main, but it it's built right, it probably won't make much of a difference unless one is competitively racing, instead of the two-boats-going-the-same-way kind of race. I've also noticed that the partially furled main does not get baggy like a partially furled headsail, indicating that they can be built to work partially furled.

If the furler mechanism jams or breaks when the sail is partially furled, that'd suck. I guess I'll get the camera out and film it ripping it self to shreds.

I've thought about adding a second clew above the existing one as a backup and sew a strong hem line from that backup clew to the tack (not cut it, just sew a reinforcement hemline to the tack) to use if the clew blows out. That might also work as tripping reef.

I'll tell you though, it is convenient to not be limited to fixed percentages of sail reduction as with slab reefing. The draw back is that I find myself continually adjusting to find the right amount. But I'm a tweaker! I move my genoa cars, I move the traveller. I guess it's from all the years racing.

Ya know, now that I think about it, since the mast slot is fairly wide, I wonder what interference it would cause if I built in tack and clew cringles (flexible so they will wrap around the furler), as well as a few reef point cringles into the sail so that I can reef it if it wont' furl. Hmm.

If the sail won't furl, I can lower it like slab reefing, then tie in a line at the tack and clew, the tidy up the bunt. Yeah, it would to look pretty, would be a PIA, but at least it wouldn't be left unfurled and unfurlable.

[robert sailor]

Originally Posted by Island Time O25

Can any CF engineers explain this to me? Everyone is saying how battenless furling main is inferior to standard battened one. Yet somehow all the sailing books say that the genoa is the driving force of the two sails and the main usually playing the 2nd fiddle. Why wouldn't 2nd genoa/jib installed as the furling main be just as "driving" as its bow counterpart?

Let's take this question further. Let's assume outside furling main with no boom and a foot as large as the bow gennie. Now we have two gennies so to speak. Wouldn't that mean 2X the driving force of one gennie? And if not - why not?

The headsail gets clean air. The mainsail gets dirty air aided by a big mast section so when your driving to windward the first several feet of sail is giving you little to no drive. Most of the drive in a mainsail going to weather comes from the last 30% of the sail so when you remove the Roach you are removing the area of the sail that is giving you most of the lift.

[Island Time O25]

Originally Posted by robert sailor

The headsail gets clean air. The mainsail gets dirty air aided by a big mast section so when your driving to windward the first several feet of sail is giving you little to no drive. Most of the drive in a mainsail going to weather comes from the last 30% of the sail so when you remove the Roach you are removing the area of the sail that is giving you most of the lift.

I see. Thanks for clear explanation. But wouldn't gaining extra foot length counteract the loss of roach? For example my boom is 14ft long so the non-furling main was limited to a 13.75' foot or thereabouts. Now if I can use a boomless furling main with a foot of say 15'-16' would that mitigate the loss of roach considerably?

[Dockhead]

Originally Posted by robert sailor

The headsail gets clean air. The mainsail gets dirty air aided by a big mast section so when your driving to windward the first several feet of sail is giving you little to no drive. Most of the drive in a mainsail going to weather comes from the last 30% of the sail so when you remove the Roach you are removing the area of the sail that is giving you most of the lift.

A great explanation.

Another thing I have learned after replacing my jib is that the condition of the jib has a huge effect on how the mainsail works. I didn't really ever guess that would be so -- first time I've ever had a new headsail without a new main at the same time.

The new jib creates a completely different air flow over the main, even the old baggy main, than the old one did, which transforms its performance. With the old jib, the forward 1/4 of the main or more was just backwinded, the rest working weakly. The new jib pulls the air flow right over the whole main and allows the main to be powered up fully in a wide range of conditions.

It may be, that in-mast furling mains are more sensitive to the condition of the headsail, than other ones on. That could be, just idle speculation on my part, because (a) fatter mast increases airflow separation problems; (b) no roach (as Robert says) meaning you are more dependent on the more forward parts of the sail which suffer most from dirty air.

I would love to hear from someone who actually understands this stuff.

[Dockhead]

Originally Posted by scherzoja

Just a quick observation about a furling main is that it only has one clew, so it better be well build. Slab reefing mains have one clew for each reef and if the unreefed clew blows out, take in a reef and get on with life. If the only clew blows out, whatchya gonna do now with the sail flapping like crazy?

I have a Hood Stoway in-mast furler (came with the boat when I bought about 4 years ago, what can i do about it?). It appears to be as old as the boat (30+ years). It seems to do well, hasn't jammed yet, no lines to override because it has a geared mechanism at the mast, which means I go to the mast and use a winch handle to crank it while easing the outhaul to furl/reduce sail area; it's not all that difficult. Only problem that has not occurred yet is what to do when the clew blows out or if I can't furl the sail. If the sail is already all the way out, just lower it like any other sail.

I know the furler main might not be as good of a performer as a normal main, but it it's built right, it probably won't make much of a difference unless one is competitively racing, instead of the two-boats-going-the-same-way kind of race. I've also noticed that the partially furled main does not get baggy like a partially furled headsail, indicating that they can be built to work partially furled.

If the furler mechanism jams or breaks when the sail is partially furled, that'd suck. I guess I'll get the camera out and film it ripping it self to shreds.

I've thought about adding a second clew above the existing one as a backup and sew a strong hem line from that backup clew to the tack (not cut it, just sew a reinforcement hemline to the tack) to use if the clew blows out. That might also work as tripping reef.

I'll tell you though, it is convenient to not be limited to fixed percentages of sail reduction as with slab reefing. The draw back is that I find myself continually adjusting to find the right amount. But I'm a tweaker! I move my genoa cars, I move the traveller. I guess it's from all the years racing.

Ya know, now that I think about it, since the mast slot is fairly wide, I wonder what interference it would cause if I built in tack and clew cringles (flexible so they will wrap around the furler), as well as a few reef point cringles into the sail so that I can reef it if it wont' furl. Hmm.

If the sail won't furl, I can lower it like slab reefing, then tie in a line at the tack and clew, the tidy up the bunt. Yeah, it would to look pretty, would be a PIA, but at least it wouldn't be left unfurled and unfurlable.

Couple of remarks:

1. If you rip out the clew with the sail jammed in the furler, at sea and with wind, you have to go aloft and cut the sail down, and scrape up funds to order a new one. I'm not sure ripping out the clew is very common. Never happened to me in decades of sailing. Even more that it would happen simultaneously with a total furler jam.

2. If you get a dead end jam in the furler mechanism which you can't clear, you flake the main up against the mast and tie it on to the mast with sail ties. It's a real PITA but can be done in reasonable weather, provided you are not single handed, by putting a man up in a bosun's chair. But jams you can't clear are pretty rare. It happened to me my first months using the system -- operator error. I didn't know how to clear it and had to do the above. With help from guys on here (five years ago!), I learned how to clear a jam, and did it fairly easily once armed with the right technique.

3. My experience with partially furled furling main is just like yours. The shape is surprisingly good when partially furled, perhaps even better than when not reefed. This is the opposite from how a headsail works, where the shape goes to hell immediately as you start to furl. I have no idea why this is the case and would love to hear from someone who understands. In any case, this is a profound advantage of furling mains, and one reason probably why they are so popular up here where the wind blows hard so often. Take two identical boats, one with a furling main, and one with a full batten main -- once the wind rises and they start to reef, the advantage of the full batten main disappears. Even my old baggy main has a quite decent shape when reefed.

4. I would not mess around with extra clews and tack cringles, if I were you. If it ain't broke, don't fix it, especially when it means more carp to get through the mast slot every time you furl or unfurl.

[Sailor Doug]

I blew the clew off my RF main. I was single handling in a club race wind was about 16-18 knots. Instincts took over, I started the motor, set that auto helm so wind was 30 degrees off starboard bow and started to pull my reeking line on my Seldan reefer. Other than being a little noise all when fine. Lesson was next week I had all the nylon straps (3 corners) on both sails replaced. Sun is pretty tough on straps, mine timed out after 10 years on the great lakes being up 6 months a year. You guys in the south need to replace them regularly.
Never ever use a winch to furl, to easy to create a jam. The following is my procedure on 36' with Seldan RF main.

1 start motor.
2 point boat 30 degrees off wind to starboard and set auto helm.
3 ease out main sheet until sail just luffs.
4 release out haul.
5 pull in reef line hand over hand. I some time stand on out haul to control tension.

People who like reeling lines are on the wrong page.



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[Dockhead]

Originally Posted by Sailor Doug

I blew the clew off my RF main. I was single handling in a club race wind was about 16-18 knots. Instincts took over, I started the motor, set that auto helm so wind was 30 degrees off starboard bow and started to pull my reeking line on my Seldan reefer. Other than being a little noise all when fine. Lesson was next week I had all the nylon straps (3 corners) on both sails replaced. Sun is pretty tough on straps, mine timed out after 10 years on the great lakes being up 6 months a year. You guys in the south need to replace them regularly.
Never ever use a winch to furl, to easy to create a jam. The following is my procedure on 36' with Seldan RF main.

1 start motor.
2 point boat 30 degrees off wind to starboard and set auto helm.
3 ease out main sheet until sail just luffs.
4 release out haul.
5 pull in reef line hand over hand. I some time stand on out haul to control tension.

People who like reeling lines are on the wrong page.

Thanks; very interesting and educational post.

I envy you being able to furl by hand. You would feel it so much better that way. Sails of our size cannot possibly be furled by hand, and even a winch is a huge struggle if it's a manual one. So we use electric winches, which means of course you don't feel anything at all. But you learn to listen to what the rigging is telling you, and you learn to read the tension somewhat.

[botanybay]

Interesting comments about listening to the hardware.

At 55' of boat I can do it with a manual winch but can pay better attention to the outhaul tension if I use the electric.

The trick I have found which works well for me is to cross sheet the continuous furling line (1990 hood system) to the electric winch across the companionway.

If it starts to sound loaded I stop and can pull on the line across the companionway. If everything moves then I know it is just loading up, if it is getting tight it won't move and I can back off at that point.

There was a comment about a list of steps to unjam a sail. I have not had any significant jams in 5 years but I would love to see that list of steps in case!!!

[Hobie_ind]

Interesting thread, but I'll admit I didn't read all 18 pages, so I'll apologize in advance if this has already been covered.

I was quite apprehensive about the in-mast furling before we bought our boat (Amel Super Maramu) but now that we've had it, I love it. Couple thoughts come to mind though. Sorry if they're a bit random.
- I had mild 'jams' early when getting used to the system. Interestingly, all were when unfurling the sail if I had gotten big wrinkles when furling either without enough tension on the outhaul, or after reefing deep downwind (which I don't typically do now unless the winds are REALLY light). All were quickly rectified. I've never had any problems jamming while reefing in, only out.
- I've never spoke to another Amel owner who's had a serious jam that wasn't able to be worked out quickly. I'm sure there have been, but it doesn't seem common and I believe if it was common it would have beat to death on the Yahoo owners group.
- I've often wondered if the ketch arrangement on the Amel seems to work better since the sail sizes are quite a bit smaller than sloops, so there's larger tolerances inside the masts?
- When we first got the boat, I felt that Amel had undersized the furling motor on the main (the mizzen is manual) as it is easy to overload it and 'burn' the brushes. After working with the system for a while I suspect this was on purpose to protect from operator error, as if the technique is right, the motor is more than adequate. Surprisingly like most things, as we practice (use it) we seem to be getting 'luckier' with the operation of it.
- Given how quickly I can reduce sail, I find we tend to carry more sail during the night than a lot of our friends with slab reefing, and the extra miles are noticeable on crossings where the winds are quite variable. Less critical when day sailing, but on longer crossings, I think this can go a long way to make up for the loss of sail efficiency on the average cruising yacht.
- I know a slab reefing sail is more efficient upwind, but if I wanted to beat upwind for long periods, I'd have probably bought a different boat, and probably not a ketch. The tradeoffs of ease of singlehanding for myself (I know lots of singlehanders use slab reefing, it's a luxury, but I'll take it) and more sleep when my wife is on watch more than makes up for the 5% of the time we're going hard to windward and cursing our sail shape (I don't miss the Caribbean - where our percentage of time spent beating to windward was much higher!)
- Finally, for really short trips we find we still sail often as the sails are so easy to take out. More than we would with slab reefing. But maybe I'm just lazy....I thought I better best somebody to that.

Just my thoughts.....there's pros and cons to everything. It's all a matter of picking the compromise that fits your needs. The perfect, all-purpose boat that meets everyone's needs just hasn't seemed to have been built yet.

Mark

[beiland]

Originally Posted by Island Time O25

Can any CF engineers explain this to me? Everyone is saying how battenless furling main is inferior to standard battened one. Yet somehow all the sailing books say that the genoa is the driving force of the two sails and the main usually playing the 2nd fiddle. Why wouldn't 2nd genoa/jib installed as the furling main be just as "driving" as its bow counterpart?

Let's take this question further. Let's assume outside furling main with no boom and a foot as large as the bow gennie. Now we have two gennies so to speak. Wouldn't that mean 2X the driving force of one gennie? And if not - why not?

I would refer you to this very informative presentation with illustrations
North Sails: How do sails work?

Take particular notice of how the genoa sail's efficiency is so much improved by the trailing sail's (mainsail) existence,...."Sails in Combination"

[Dockhead]

Another furling main data point:

Our new carbon laminate mainsail has a straight leech and four short vertical carbon fiber battens.

I took a conscious risk of jamming problems when I ordered this sail -- some people have had problems with battens in furling mains.

I now have about 750 miles on the new mainsail and so far no problems with the battens. You can't feel the battens as they go in and out of the mast, and the laminate sail furls tighter and easier since it is less bulky than the Dacron one. The straight leech surely plays a role in the dramatic performance increase compared to the hollow leech Dacron sail. The battens are very thin carbon rods -- that also might play a role.

That's just one data point, and YMMV, but so far so good in my case.