In-mast furling - pros and cons

[Magnum]

A friend of mine is seriously considering buying a new Jeanneau 57. Like myself he's an experienced mobo'er, and he has sailing experience, but this will be his first sailing boat.

He's keen to make his sailing as stress-free and easy as possible so has suggested that the in-mast furling option might be a good idea. I think he could be making a mistake. Here was my response.

"It's an entirely personal matter but I think you might regret going for in-mast furling. Although you quite rightly say you are not concerned about the last 1/2 knot or so it is my understanding that an in-mast furling mainsail offers quite a bit less performance that a conventional sail. The problem with in-mast furling is twofold. Firstly there are no battens, because of course it has to be furled into the mast. This is going to make the sail less stiff and that will affect performance. Secondly, as a result of the lack of battens there can be no roach and this significantly reduces sail area. There's a quick explanation here - http://www.cruisersforum.com/forums/f47/in-mast-furling-15121.html#post161607 . Take a look at the J57 spec and you'll see the standard mainsail is 807 sq ft whereas the in-mast furling mainsail is just 624 sq ft. That's a big difference and something you'll really notice when battling against a few knots of tide. My suggestion is to forego the extra convenience of in-mast furling and go for the slightly less convenient but more efficient slab reefing arrangement."

I would be very grateful for comments on the above

 

[sarabande]

there are some in-boom reefing systems which overcome the lack of battens and roach issue. But given the technology of modern battens and cars, a standard main not furling into the mast can be automated well.

I'll ferret and post.

EDIT

Jeckells Sailtainer, for starters:-

http://www.jeckells.co.uk/sails/in-boom-reefing-system/

and

many others from a search "in-boom reefing"

http://www.furlboom.com/descript.htm

 

[Kelpie]

I have a little experience of in-mast systems on a 42ft Jeanneau. Perhaps the biggest overall advantage was that, just like a roller headsail, you can make small adjustments in sail area quite easily. So 'taking a reef' is not such a big decision.
I'm not sure about how much more convenient it is, though. It takes quite a bit of time to fully stow the sail (or unfurl it, for that matter). I think a well maintained conventional system would possibly be quicker to drop, especially something fully battened that drops into a stack-pack.
The main drawback is that the system doesn't always work perfectly. In my (limited) experience it is quite possible to put creases into the sail as you roll it away. And there is always that big fear of getting the whole lot jammes aloft which on a large baot is potentially terrifying.

On the other hand, some people swear by furling mains... I've just finished reading 'Time On Ice' whose clearly very experienced authors preferred this system for their Antarctic expeditions.

 

[SHUG]

I think this topic may have been raised about ten times previously and it seems to boil down to personal preference and priority.
My preference is NOT to have in-mast furling as I have seen many instances of this system stuck fast and unable to go in or out. When it is new with crisp sails it works well but the trouble comes later with baggy sails which have lost their slippiness and crease and jam.
Each to his own choice...!!!

 

[Ex-SolentBoy]

I debated this very question long and hard before buying my new boat. Whilst what you said was true some time ago, things have moved on. Our in-mast main has vertical battens and plenty of roach. I doubt there is much speed loss if any, and we have the advantage of infinite reefing scope and ease of handling.

I also like the way it is much easier to control the shape of the foot of the sail. Easing on the outhaul is much more effective than relying on sail shape alone in that area.

If there is a downside, I think it is the extra weight aloft, but that depends on the boat and it's usage.

We have switched from conventional to in mast, and having sailed both, my preference is the latter. For a new boat owner I would not hesitate to recommend in mast.

 

[Magnum]

SolentBoy. Interesting, but look at the mainsail size difference on the Jeanneau 57, and that's a new boat. If it were possible to have an in-mast furling mainsail of the same area as a conventional sail then surely it would be offered? Also how can you have roach with vertical battens? Surely there can't be much stiffness?

 

[idpnd]

I was fairly terrified abotu the in mast furling on my 'new to me' boat, having never used it before.

I am pleased to report that it works very well, and allows all sail handling to be conducted from the safety of the cockpit.

 

[photodog]

I think that you have pretty much summed it up there Magnum....

I would add that with a fully roller bearing batten cars, and a lazy jack system... ala PeteHB of this parish on his Vancouver.... I can see no reason for a in mast system..

I was Gobsmacked at how easy sailhandling becomes with a good roller bearing system... that is on my list now!

 

[jonic]

I have sailed 10,000 miles both with in-mast and 10,000 miles with a fully battened main and Lazyjack system as a long distance sailing husband and wife team.

The battens were always catching on the lazyjacks and I had to go forward every time to reef. No such problems with the in-mast. It got a bit stuck on a handful of occasions, but no dramas and easily rectified.

I prefer the in-mast for ease of use.

If I was interested in performance then perhaps battend main on roller cars with everything led back to the cockpit would be ideal.

 

[Woodlouse]

The fact that you always have the weight up the mast is the main drawback to in mast furling. Normally not a problem but it will cause you to roll and pitch more in rough weather.


Other than that though the only problem is that it can be almost impossible to fix if it does all jam up. Sometimes to the point that the sail has to be cut out if it's badly stuck.


Slab reefing is a bit more work day to day, but a lot simpler when things start to go tits up.


However, lots of boats use in mast furling happily. Problems I think, especially bad problems, are fairly rare.

 

[Ex-SolentBoy]

SolentBoy. Interesting, but look at the mainsail size difference on the Jeanneau 57, and that's a new boat. If it were possible to have an in-mast furling mainsail of the same area as a conventional sail then surely it would be offered? Also how can you have roach with vertical battens? Surely there can't be much stiffness?

I can't speak for e sail sizes on the Jeanneau. My boat is also brand new - a Rustler 44. Interestingly, the main on the in mast
Rustler 44 is actually bigger than the main on the conventional cutter rigged. My understanding is that this is to do with balance.

We have as much roach as is possible. To be honest, any more and we would be hitting the backstay. With proper sail cut and strong battens I think there is quite enough stiffness.

Having said all that, I think the decision for this type of rig is really down to handling preference. There are so many of both types that they both clearly work. The differences are very small.

All I know is that I much prefer in mast. The sail pops out in seconds with virtually no effort, and one person can furl it in about 20 seconds. No lazy jacks to get caught on. No stack pack to zip up. No cover to put on around the head of the sail, no reefing lines hanging in the cockpit.

I am definitely a convert.

 

[snowleopard]

I have heard of a few potential problems with in-mast. The first was on a HR 36 where one of the full-length vertical battens broke. They discovered (in mid-Atlantic) that they could only extract the batten from the upper end of the pocket so had to go the rest of the way with it splintered and chafing.

I have sailed on an Island Packet with in-mast. When working it was wonderful to be able to reef and set without leaving the shelter of the spray hood. OTOH it was an un-battened sail and of poor quality so it set poorly but, much worse, the bagginess resulted in large creases while furling that caused the sail to jam.

Vertical battens do a good job of holding out the roach but they only work if they can be kept exactly parallel to the luff when furling. If they enter the slot at an angle they will jam instantly.

 

[Tranona]

Somewhat surprised at the loss in sail area on the Jeanneau. However I doubt that in normal crusing there will be little difference in the key measure, which is passage times. This is because the sail area and balance is instantly and infinitely variable with little effort. The boat in question is a cruising boat with no pretensions to high performance and in mast (along with a powerful engine and a bow thruster) make it very usable with a small crew.

Don't think that there is any doubt that you can extract more performance out of a tweakable slab reef system and that modern (expensive?) sail handling sytems have made them easier to use, but for relaxed cruising an in mast has a lot to commend it. Clearly the buying public agrees as the majority of production cruising boats use it!

 

[Magnum]

The sail area data is inconsistent on the Jeanneau site. Here are some other figures for the 57 that I found on another part of the site.

In-mast furling mainsail 721 sq ft
Fully-battened mainsail 850 sq ft

Better, but the conventional mainsail still has 18% more area. Wouldn't this be quite noticeable in light winds?

 

[rwoofer]

I think you are correct in your recommendation, if performance does matter. I've had a furling main with vertical battens and it did address a lot of the typical criticisms for furling mains by having a positive roach and a bit of fullness. However I still think it was some way off a proper main, which is just much easier to set well (cause that is the only thing it has been designed to do well) and you can use controls like the backstay, which I really missed with in-mast.

Having said that I do think the argument for in-mast or in-boom gets stronger as you get bigger. People tend to tweak their rigs less when they are bigger (cause the forces are greater), eroding some of the benefit of a normal main. Also the boom can be too high for people to pack the sail away easily (I know someone who had a Jeanneau 54 and experienced this very problem) - not a problem for you or I If you add an owner who is not that fussed about the last bit of performance, then in-mast looks quite compelling.

Here's a pic of an Oyster 655 with an in-main that does not look too bad.

 

[Tranona]

The sail area data is inconsistent on the Jeanneau site. Here are some other figures for the 57 that I found on another part of the site.

In-mast furling mainsail 721 sq ft
Fully-battened mainsail 850 sq ft

Better, but the conventional mainsail still has 18% more area. Wouldn't this be quite noticeable in light winds?

Yes, it will be, but in reality most people will fire up the donk. The difference in being able to squeeze half a knot extra is barely noticeable in the whole scheme of things. Different if you are buying a boat for ultimate performance - but then you would not (probably!) have a Jeanneau 57 on your short list.

Anyway in light airs a clean bottom and a folding/feathering prop will improve boat speed by more than the difference in mainsail area.

 

[Boo2]

I have heard of a few potential problems with in-mast. The first was on a HR 36 where one of the full-length vertical battens broke. They discovered (in mid-Atlantic) that they could only extract the batten from the upper end of the pocket so had to go the rest of the way with it splintered and chafing.

Couldn't they have laid head to (to a parachute sea anchor ) dropped the main and removed/repaired the broken batten ?

Boo2

 

[Twister_Ken]

A lot of the really big boats now have in-boom. I'd have thought with a 57 footer that was a realistic option, although maybe not one on Jeanneau's price list.

 

[prv]

one of the full-length vertical battens broke. They discovered (in mid-Atlantic) that they could only extract the batten from the upper end of the pocket so had to go the rest of the way with it splintered and chafing.

Couldn't they have laid head to (to a parachute sea anchor ) dropped the main and removed/repaired the broken batten ?

How do you remove it when the broken-off part is twelve feet down a narrow pocket in the sail?

How do you drop a sail that has vertical battens, anyway? It must be possible, for laying up, repairs, and replacement, but if the battens are rigidish and only extractable from the top, how on earth do you get the thing down? Feed it all over the side into the water?

In the case described, I'd have been thinking about unpicking the closed bottom of the batten packet to get the broken part out, then sewing it up again. Has to be less traumatic to the sail than having a splintered end of fibreglass inside it chewing away.

Pete

 

[Talulah]

How do you remove it when the broken-off part is twelve feet down a narrow pocket in the sail?

How do you drop a sail that has vertical battens, anyway? It must be possible, for laying up, repairs, and replacement, but if the battens are rigidish and only extractable from the top, how on earth do you get the thing down? Feed it all over the side into the water?

In the case described, I'd have been thinking about unpicking the closed bottom of the batten packet to get the broken part out, then sewing it up again. Has to be less traumatic to the sail than having a splintered end of fibreglass inside it chewing away.

Pete

Our vertically battened main has the batten pockets open at the base of the sail.
When I have had a broken batten it's not taken much for it to drop down to be extracted.
The battens are not one continous length. They are put together like a chimney sweeps brush. You push a section up the batten packet. Add the next section and continuing pushing up.
To drop the sail you just pull out the battens from the bottom of the sail a section at a time.