Experiences with in-mast furling

[matt1]

Never used in mast furling or even witnessed it in action but readily admit to having somewhat of a prejudice against it. However, it seems to be de rigueur on most new boats over a certain size, to the extent that re-sale could be an issue if you didn't opt for it when buying a new boat! I bet SIBS will be full of in mast furling.

As I see it the pro's are:-

* Easier to deploy and stowe a big mainsail when shorthanded
* Less windage once stowed
* Can set the exact amount of rqd sail area

I envisage the con's are:-

* Sail shape / set never looks as good, unless you buy v expensive cloth with vertical battens and even then I doubt it's as easy to trim a nice shape
* Can jam
* Not as kind to the sail when stowed, Vs flaked over a boom
* Increased weight aloft
* Precludes having a tapered mast section
* Can't bend rig as much to flatten sail (am guessing that may be the case anyway)

Would be interested in views from those who have USED in-mast furling. Have I missed something?

Having read the thread about jammed in mast furling, I am setting that aside for now and just theoretically considering the pro's and con's of the set up, with the presumption it works reliably.

 

[capnsensible]

In my experience, properly set up (boom height and all that) in mast furling makes passagemaking shorthanded even more of a pleasure.

Only racers would notice the performance difference so for the average sailor, their families and friends will be lovin a safe easy to operate saily boat.

Enjoy!

 

[Dockhead]

You are right on some of the drawbacks, but wrong on others, and you missed others.

Drawbacks:

Weight aloft
Lack of roach -- big performance hit
No mast bending

Advantages:
Ideal storage of the sail rolled up inside the mast (contrary to what you posted) -- so in-mast furling sails last much longer.
Reefing without heading up (can be really important in big sea conditions)
Infinite variability of sail area, achieved effortlessly, so you can easily have always the right amount of sail area
Good shape when reefed -- sail gets flatter as it goes in.

Not a drawback:
Jamming, when the sail is not baggy and is used correctly.


My experience is based on 9 years of long-distance cruising with it, on a Moody 54. This year we sailed from Cowes to Scorsebysund, Greenland, via Faroes and the Eastern Fjords of Iceland -- 4000 miles in latitudes up to 71N.

I have been planning for some time to build a new custom build boat, and have been developing the design brief for some time. I always thought this boat would have normal slab reefing, but after this last trip I am starting to think more about sticking with in-mast furling.

I think in-mast furling is useless for coastal sailing or sailing in mild latitudes, where you hoping for more power all the time. But for high latitude or blue water sailing -- in-mast furling has some huge advantages. Particularly pleasant is the sail shape when reefed. I use a 95% blade jib most of the time, carbon laminate, and with no reef points. This goes with in-mast furling like cookies and cream -- I regulate sail area exclusively with the mainsail, which is so easy to reef and which gets flatter and lower drag, the further you reef it down. The mainsail is also carbon laminate, with vertical battens -- expensive, but an in-mast furling main lasts about twice as long, so it is worth it.

The other really pleasant thing is being able to reef it without heading up. I've been in a terrible situation running off in a F9 with slab reefing when I needed badly to reef, but the sea was already up and breaking and I just didn't dare to turn upwind to get the main down. This problem wouldn't exist with in-mast furling.

So in summary -- you won't like it if you are a keen sailor, in coastal and mild latitude situations, typical weekend and summer holidays sailing. The lack of roach gives up a huge amount of power in light conditions. But if you venture further afield in stronger conditions -- you might like it very much indeed.

 

[Mataji]

People’s prejudice against in-mast reefing is just the same as many people’s prejudice against driving automatic cars. Once you’ve switched to automatic however, not many people want to switch back. Same with in-mast reefing.

 

[PHN]

This year we sailed from Cowes to Scorsebysund, Greenland, via Faroes and the Eastern Fjords of Iceland -- 4000 miles in latitudes up to 71N.

What a coincidence. I was in Scoresbysund as well. We noticed a Red Ensign sailing yacht and we were wondering why they had in-mast furling on an expedition like this. Have some pictures. We also talked to a group with sea canoes and a SUP board in Harefjord if I am correct.

 

[Yngmar]

As I see it the pro's are:-

* Easier to deploy and stowe a big mainsail when shorthanded
* Less windage once stowed
* Can set the exact amount of rqd sail area

You forgot some:
* No faffing around with lazyjacks, sail ties, zips or covers after you've arrived somewhere. Just furl and hop in for a cooling swim.
* The sail lasts longer. I say this because I see a lot of boats anchored here in the med all day long, with fully battened sails tied but not covered, getting blasted by UV because the users are too lazy/sweaty to put the covers on, sometimes for days. No, not just charterers.

I envisage the con's are:-

* Sail shape / set never looks as good, unless you buy v expensive cloth with vertical battens and even then I doubt it's as easy to trim a nice shape
* Can jam
* Not as kind to the sail when stowed, Vs flaked over a boom
* Increased weight aloft
* Precludes having a tapered mast section
* Can't bend rig as much to flatten sail (am guessing that may be the case anyway)

Mostly right. You can have short vertical battens, which we do and find a good compromise. We didn't want full length ones because they're a horror to deploy and you can no longer drop the sail in an emergency (which we never had to).

Yes they jam if used incorrectly. We have jammed ours a few times (I think three or four times in 3 years). The first time because I hadn't read the manual yet and the sail was 15 years old and quite knackered. The other times for various reasons, mostly related to sloppyness caused by either being very tired or inattentive. We know how to unjam it now and it's not that dramatic. Nobody had to climb up the mast. Takes a few minutes depending on conditions.

I think it's probably kinder to roll it up neatly than to flake it and then turn the flake into a permanent crease with the help of sail ties tied too tightly.

Yup, more weight aloft (but less junk hanging off the boom, and less weight in total due to absence of reef lines, blocks, jammers, etc.). If you don't like the weight aloft, there's a thread about in-boom furling nearby. We don't seem to roll more than other, similar boats (with fully battened sails) though.

I don't see a lot of tapered masts on boats with fully battened sails either. I think that's a bit of a made up point, at least for the cruising sector.

You can bend the mast as much as you want, you just have to remember to release the backstay before furling, that's the key difference. Which is a bit annoying on our boat, as the backstay tensioner is controlled at the backstay, with a winch handle (so you have to leave the centre cockpit).

Oh, one more downside is the maintenance - stripping the in-mast furling winch for servicing is a bit more involved than greasing a luff groove.

Due to the nature of the in-mast furling, it generally furls happier on a starboard tack, especially if you have any kind of battens in the sail. Up to the first batten (which we use as "first reef"), it doesn't really matter so much though.

Overall I'm happy with ours and wouldn't want to trade for a fully-battened one. Maybe a junk rig though ;-)

The ease and speed of use mean we are quicker to get the sail out and use it more often and on shorter passages. Also I've really come to appreciate the "furl and done" part of it. When arriving at anchor, we like to swim as soon as possible

 

[Sticky Fingers]

I'll add my two penn'orth. I bought a new 42' yacht last year and opted for in-mast, with laminate sails including fully-battened main, and electric winches. I sail with my wife (a beginner, or she puts it, "incompetent crew") and I'm in my 60's, not very agile. Main driver for this decision was the ability to unfurl and furl from the cockpit with minimal effort, in any wind conditions, any amount of sail, unaided. So far (and that's not very far) it's been excellent. It's a Selden system using a furling winch on the mast with a continuous line and two clutches on the coachroof, adjacent to that winch. The sail sets very well, it's very responsive to sail shape changes using vang, outhaul and backstay, and the fully battened roach is OK (not up to a laminate slab though). Would I have it again? yes. What would I change? Well, the only niggle is the continuous furling line which is a bit of a faff and a bit slow, so I'd have an electric or hydraulic furler installed on the mast. Works for me.

 

[Tranona]

Agree with most of the above with perhaps the exception of extra weight aloft which I think for boats designed for in mast is way over exaggerated. The stability figures are exactly the same for both versions of my boat. Designers are well aware of the potential issues having been designing boats with in mast for getting on for 30 years. I think this issue arises from the early add on systems which really did add extra weight aloft, mainly in the extra extrusion.

I have had 2 boats within mast and my observations are that the current one benefits even more because it has a mainsail orientated rig with 106% jib so most reefing is done by reducing the mainsail which of course is not limited to defined reductions. Boats with big overlapping genoas and small mains like the old IOR influenced designs benefit less.

Never had any problems with the mechanics such as jamming, perhaps because it is easy to follow the instructions for trouble free operation. On my size sail (30 sqm) I rarely need to use a winch.

My only negative comment is aimed more at my bad decision, and that is not opting for a better mainsail.

The big plus though is that it allows me to continue to sail single handed comfortably controlling everything from the cockpit. Important when you are well over 70 and hope for a few more years of the same.

 

[Sticky Fingers]

I'm impressed with the laminate sails. Very good, upwind performance is excellent. Quite a bit extra though.

 

[Gwylan]

We have in mast main, not my choice but it came with the boat. Been fine since 2006.

Works very well for the lightweight crew and me.
Easy to reef single handed too.
No need to leave the cockpit!

As everyone says it gives you an infinite variety of sail settings.
Easy to change, adjust. Keep the helm effort low and comfortable.

No lazy jacks, bags or different colour strings for the crew to confuse.

After we fitted a new mainsail, without the dowagers flop, we have had no problems jamming.

You probably will not win any races but you will be comfortable and in control in every type of weather. No brainer.

 

[johnalison]

Like all surveys with self-selected responses, it is inevitable that most answers will be positive. I don't have a furling main but I have sailed with it on occasion. I don't think that a furling main is quite in the same category as a furling jib, ie almost indispensable, but nor do I think it is as bad as sometimes portrayed. I suspect that the OP if he is seriously thinking about getting one has already answered his own question, but some disadvantages will have to be accepted. I can see that modern designers will now be designing boats to incorporate the need for a furling main, and radar, aloft but it must also be the case that a boat without these will benefit from less weight aloft.

 

[Tranona]

I can see that modern designers will now be designing boats to incorporate the need for a furling main, and radar, aloft but it must also be the case that a boat without these will benefit from less weight aloft.

Where does the "will be" come from, when as I pointed out earlier boats have been designed with in mast for 30 years. Indeed with your own brand - HR 90% of the boats built over 40' have in mast as standard. Would be very surprised if German frers was not fully aware of any weight issues and possible effect on stability - and taken this into account when determining the ballast for example.

Incidentally I have never seen any quantification of the additional weight aloft that is claimed. Suspect this claim is in the "everybody knows" category and therefore does not need evidence to support it.

 

[{151760}]

Where does the "will be" come from, when as I pointed out earlier boats have been designed with in mast for 30 years. Indeed with your own brand - HR 90% of the boats built over 40' have in mast as standard. Would be very surprised if German frers was not fully aware of any weight issues and possible effect on stability - and taken this into account when determining the ballast for example.

Incidentally I have never seen any quantification of the additional weight aloft that is claimed. Suspect this claim is in the "everybody knows" category and therefore does not need evidence to support it.

These are my ill-informed thoughts. With a mainsail fully hoisted, (some) of the weight is distributed over the length of the mast. With a slab reef, the weight becomes concentrated lower down. With an in-mast furler all the weight, plus the weight of the roller, stays high up. Whether that is significant to the stability of the boat I very much doubt. As you say in-mast furlers are a mature technology; designers have long since factored them in to their calculations.
I can remember similar debates about roller-furling headsails. Who but a few die-yards worries about them now? The potential risks from furler problems are far outweighed by the risks incurred changing sails on a plunging foredeck.

 

[Seven Spades]

I have just bought a boat with electric in-mast reefing and I can't say that I am confident with it yet. It seems I have to power it out and tension the outhaul at the same time to unfurl it. Furling it is easier it looks like ou need some tension on the outhaul or it won't be tight enough.

 

[Sticky Fingers]

I have just bought a boat with electric in-mast reefing and I can't say that I am confident with it yet. It seems I have to power it out and tension the outhaul at the same time to unfurl it. Furling it is easier it looks like you need some tension on the outhaul or it won't be tight enough.

Yes that's my experience, the continuous furling line is a bit of a faff. Unfurling single handed I do in chunks, unfurl some then tension outhaul. Repeat till you have enough sail. Furling needs some juggling to keep the outhaul taut and some tension on the lazy end of the furling line.

 

[johnalison]

Where does the "will be" come from, when as I pointed out earlier boats have been designed with in mast for 30 years. Indeed with your own brand - HR 90% of the boats built over 40' have in mast as standard. Would be very surprised if German frers was not fully aware of any weight issues and possible effect on stability - and taken this into account when determining the ballast for example.

Incidentally I have never seen any quantification of the additional weight aloft that is claimed. Suspect this claim is in the "everybody knows" category and therefore does not need evidence to support it.

I am working by analogy with the 'remove weight from the ends' principle. The boat may be perfectly satisfactory with the additional weight aloft, but that doesn't mean that removing this weight won't have benefits, though the roll rate will be increased.

I agree that it would be interesting to know what additional weight is carried aloft with a reeefing main. This weight would appear to have two components. In the first place there is the fixed weight of the gear. I have no idea what this amounts to but I imagine that with modern rig it is quite low. the second component is the additional weight when the sail is reefed. With my slab reefing, by the time I have put in my second (of two) reefs most of the considerable weight of the main is tied down at boom level and the rest some five metres lower. I believe that this could have a noticeable effect on the boat's behaviour and that without a furling main or radar on the mast my boat is the better for it.

 

[maby]

Anyone know the cost of the Seldon conversion to electric in-mast furling? I have to say that it is sounding attractive!

 

[Sticky Fingers]

Anyone know the cost of the Seldon conversion to electric in-mast furling? I have to say that it is sounding attractive!

Does yours already have in-mast with the mast-mounted winch?

 

[Tranona]

I believe that this could have a noticeable effect on the boat's behaviour and that without a furling main or radar on the mast my boat is the better for it.

I think that is the crux of the argument - you believe it is better. Nothing wrong with believing - we all think we can notice a difference. However the extra weight (which I agree is likely to be small) should have a quantifiable effect such as changing the period of roll, altering the GZ curve or the AVS if it is significant. None of the published data shows either of the last two differently for the in mast versions of boats. Although roll can be measured, it is not usually shown so is probably subjective.

I wonder if one sailed blindfold in conditions where these changes in this behaviour might occur, you could actually tell what kind of rig the boat had.

To me the main downside is a sub optimal mainsail. with my last boat this was not a big issue because performance under sail was low on the priority list when I bought it, but my new boat is inherently a much better sailing boat and as I suggested earlier I made a mistake in not specifying better sails. Planning to have the main recut next year based on advice from the sailmaker who has sailed it, and if that does not work then bite the bullet and buy a new sail.

 

[maby]

Does yours already have in-mast with the mast-mounted winch?

It does. I gather that there is an optional add-on from Seldon which is the electric drive to attach to (or in place of) the mast-mounted winch.

On the subject of weight distribution, surely there is only a significant difference between in-mast furling and traditional furling when the sail is furled? With the sail unfurled, the weight is pretty much distributed the same for both.