Traditional Main vs In-mast Furling

[Dockhead]

Originally Posted by daletournier

This is also true,both points.

Regarding performance, some lean more that way, Dh for one seems to enjoy getting the most out of his boat. Many others myself included dont pay as much attention to sail trim etc therefore the performance limitations of a inmast furling system arent that important and really from a cruising perspective the performance thing is minimal. Dont get me wrong i like some performance but im not sure the difference between the rigs is that much over many miles and varing conditions.

This year Sukha as cruised 7,200nm and we have averaged just under 6.2k, sailing 99% of the time.

Wow! Few of us sail that many miles in a year; that's about double what I did.

One important thing to keep in mind about in-mast furling -- the performance hit from in-mast furling disappears as soon as you start to reef. Moreover, in-mast furling sails are cut flatter, so they naturally perform better in strong wind because they produce less drag.

I think that's one reason why in-mast furling is so popular up here in the UK -- almost universal on cruising boats 40 feet and over made in the last 15 years. We have a lot more wind than you have in Florida, the Med, etc., due to the latitude.

The performance hit of in-mast furling would be frustrating in a place where light winds prevail. To get power in light wind, you need roach, and you need a fuller shape.

[daletournier]

Originally Posted by Dockhead

Wow! Few of us sail that many miles in a year; that's about double what I did.

One important thing to keep in mind about in-mast furling -- the performance hit from in-mast furling disappears as soon as you start to reef. Moreover, in-mast furling sails are cut flatter, so they naturally perform better in strong wind because they produce less drag.

I think that's one reason why in-mast furling is so popular up here in the UK -- almost universal on cruising boats 40 feet and over made in the last 15 years. We have a lot more wind than you have in Florida, the Med, etc., due to the latitude.

The performance hit of in-mast furling would be frustrating in a place where light winds prevail. To get power in light wind, you need roach, and you need a fuller shape.

To many miles as far as im concerned.. Lol. thats why I've decided to stay here in the Seychelles for the next eight mths....rest....lol.

[Snore]

I am not a fan of in-mast for all the reason cited.

That said, most of the boats I operate have in-mast furling. If you go in-mast, read the manufacturers recommendations on how to operate the unit you buy.

My experience has been that as long as tension is kept on the outhaul and furling lines such that the foot and leach are fairly straight- all is well. The issue is doing keeping tension when it is blowing like hell. Or at night when a thunderstorm catches the crew unaware.

There are two major types of in-mast systems (and a few weird one I ). I believe it is Selden furling that requires you to go out to the mast to flip the winch from free to ratchet to unfurl/furl the main. If you go in-mast you should be able to operate it from the cockpit.

Although if you go stack-pack you will need to go forward to reef- but the sail shape on a conventional always looks nicer.

[CruiserAD]

I just bought a Broadblue 38 catamaran from 2002 this summer and sailed it from UK to Germany. The boats intended usage is extended single handed offshore cruising. Even though it is a cat it has got a very small mainsail because of the mast being very far aft, as well as having backstay preventing a "loafy" or square-top mainsail.

The boat has in-mast-furling mainsail. This was not my choice, but since the other aspects of the boat suited my needs very well I did not make this a deal killer. The sail works OK but was rather hard to furl and unfurl, presumably due to lack of maintenance. One also need to be careful not to jam the furling line on the grooved drum due to the rather "close" angle of the line entering the drum.

I have so far only had inmast furlers on some charter boats and I avoided it if ever possible. One once nearly knocked my head off with s free-spinning winch handle when trying to reef. This was clearly my own fault (RTFM!!) but with crushed glasses and blood all over the face I was very lucky not getting even worse injuries. So it did not really increase my faith in this type of setup.

I'm clearly NOT a competitive sailor, but rather a sailing traveller and used a traditional main on my previous long distance cruiser for some 35'000 miles.

So given all this background I was totally determined to replace it against a traditional slab-reefing mainsail, even if it would cost me a lot of money and the additional performance of such a setup will be very limited due to the small size of the main (the boat is clearly driven by the large foresails). But it would be - so I thought - a system with less risk for problems when out alone.

Now this discussion - especially all these happy owners of inmast furlers praising the simple handling in bad weather and the fact that I do not get any younger - makes me wonder if I'm doing the right thing when ripping out a working in-mast furler and placing a track on the mast instead. Maybe I better spend (part) of the money for a proper servicing and rigg-trimming...?

Thanks for all the good advice in this thread

[Dockhead]

Originally Posted by Snore

. . . I believe it is Selden furling that requires you to go out to the mast to flip the winch from free to ratchet to unfurl/furl the main. If you go in-mast you should be able to operate it from the cockpit. .

In normal use, you leave the Selden mast winch on "Free". You only use the "Lock" position if you have a broken furling line and you are operating the unit from the mast with a winch handle.

[Lost Horizons]

Originally Posted by Martkimwat

Whatever one might say about it's reliability or not, you cannot deny that it is an awful lot of extra weight and windage aloft and if you are going to sail offshore for any length of time, you are bound to end up eventually experiencing storm force conditions, and that's when you will wish you didn't have all that extra top hamper.

The difference in weight only exists when motoring, and then the extra weight will act as a roll dampener.

[Lost Horizons]

Originally Posted by Deltasailor

I have a Jeanneau 371 with in mast furling. I HATE IT! I have never owned a boat with mast furling but give me slab reefing every time. If the in mast sail is new maybe it will furl but if it is not flat as a table cloth IMHP it will be a sod to furl or unfurl. Don't bother, get a traditional stack pack.

Your first and third sentences contradict each other. Which one is true?

[Lost Horizons]

Originally Posted by Dockhead

And it makes the boat roll more downwind and at anchor.

It is the opposite. Take a stick by its end and roll it with you arm. Now take the same length heavier stick and try rolling it. The difference will be apparent.

This fenomenon is called moment of inertia in physics.

[S/V Illusion]

Originally Posted by Dockhead

I had heard horror stories about battens and in-mast furling. My sailmaker told me that there is no problem with them IF you have two things -- a modern in-mast furling system like Selden which has a wide slot in the mast, AND the batten pockets are properly designed to be snag-proof. The pockets have to open to the bottom, BTW. I took the risk and went for it, and have had zero problems. The battens make a huge difference, eliminating the floppy leech which I hated on my previous mainsail.

As others have said, jamming occurs when furling OUT, not in, and you learn pretty quickly how to prevent it.

As to furling off the wind -- you do have to at least partially depower the sail before furling -- feather the sail by putting the vang on and letting off the mainsheet, and/or slacking the outhaul. Note that it works much better on one tack rather than the other because of the direction of furling vs. position of the mast slot. On one tack (port on my boat), the sail has to turn almost 180 degrees to get onto the furler, if the boom is far out, and so naturally this means more friction and more load on the furling gear. On the starboard tack it's easy peasy -- hardly even have to depower the sail.

You just answered your own question as those are only some of the problems which must be overcome as examples of 'self-inflicted' problems people subject themselves to by choosing mast furlers.

[daletournier]

Originally Posted by S/V Illusion

You just answered your own question as those are only some of the problems which must be overcome as examples of 'self-inflicted' problems people subject themselves to by choosing mast furlers.

Do you own one? If so how many miles have you done with it....seriously? Is your view based in experience or heresay?

I use the example of amel super maramus, arguable one of the best ocean crossing boats out there. Now they dont just have one inmast furler but two? Have you met an Amel owner? they secretly believe their boats were designed by god!! Ive met many and i can asure you not one has ever complained about their electric inmast furler. If they were so bad and problematic don't you think these blue water go around the world cruisers would still be using them?

I was influenced by the type of comments such as yours and i feared them, BUT ive now talked to many world cruisers that have them and guess what? they really like them. Secondly i just crossed the indian ocean, no inmast furler disaster.

[Dockhead]

Originally Posted by Lost Horizons

It is the opposite. Take a stick by its end and roll it with you arm. Now take the same length heavier stick and try rolling it. The difference will be apparent.

This fenomenon is called moment of inertia in physics.

It's called "polar moment of inertia", and more of it makes rolling worse. Just like more weight in the bow or stern makes pitching worse. More polar moment of inertia means rolling or pitching is harder to initialize, but once started, keeps on going. LESS weight aloft is definitely a good thing.

[Lost Horizons]

Originally Posted by Dockhead

It's called "polar moment of inertia", and more of it makes rolling worse.

Are you sure?
As far as I remember, polar moment of inertia is materials resistance to bending. A mast resisting rolling motion is a classic case of moment of inertia. Have you tried anchoring on a sailboat without a mast?

[Lost Horizons]

Originally Posted by Dockhead

It's called "polar moment of inertia", and more of it makes rolling worse. Just like more weight in the bow or stern makes pitching worse. More polar moment of inertia means rolling or pitching is harder to initialize, but once started, keeps on going. LESS weight aloft is definitely a good thing.

What you just added about dynamic behavior is correct, however it hardly applies to an anchored boat. Certainly agree about less weigh aloft being better, but resisting motion at anchor is one exception.

[nodiesop]

Originally Posted by CruiserAD

I just bought a Broadblue 38 catamaran from 2002 this summer and sailed it from UK to Germany. The boats intended usage is extended single handed offshore cruising. Even though it is a cat it has got a very small mainsail because of the mast being very far aft, as well as having backstay preventing a "loafy" or square-top mainsail.

The boat has in-mast-furling mainsail. This was not my choice, but since the other aspects of the boat suited my needs very well I did not make this a deal killer. The sail works OK but was rather hard to furl and unfurl, presumably due to lack of maintenance. One also need to be careful not to jam the furling line on the grooved drum due to the rather "close" angle of the line entering the drum.

I have so far only had inmast furlers on some charter boats and I avoided it if ever possible. One once nearly knocked my head off with s free-spinning winch handle when trying to reef. This was clearly my own fault (RTFM!!) but with crushed glasses and blood all over the face I was very lucky not getting even worse injuries. So it did not really increase my faith in this type of setup.

I'm clearly NOT a competitive sailor, but rather a sailing traveller and used a traditional main on my previous long distance cruiser for some 35'000 miles.

So given all this background I was totally determined to replace it against a traditional slab-reefing mainsail, even if it would cost me a lot of money and the additional performance of such a setup will be very limited due to the small size of the main (the boat is clearly driven by the large foresails). But it would be - so I thought - a system with less risk for problems when out alone.

Now this discussion - especially all these happy owners of inmast furlers praising the simple handling in bad weather and the fact that I do not get any younger - makes me wonder if I'm doing the right thing when ripping out a working in-mast furler and placing a track on the mast instead. Maybe I better spend (part) of the money for a proper servicing and rigg-trimming...?

Thanks for all the good advice in this thread

...and I think there is more. I have to confess, I cannot say that I would have alot of experience with in mast furls. I had that on a 52 foot monohull. And with the size of the sail it was easy handling. Since I am the same type of sailor as you are (traveller) I do not really care if I can make 0.213 knots more. For me, mainly to things count:

1. ease of handling
2. reliability

and I think that is what the discussion mainly is about. I really doubt, that the majority of us is doing Volvo Ocean Races with pots, pans, cups and a microwave oven on board.

(bit the same as a collegue of mine once said to me: 'why do you care about your new bycicle to have 1 kg less? ...loose one kg from your hips and it sums up to the same

so.... having said that, this is pretty much my thinking. Perhaps we should have some statistics to prove that one system is less reliable than another.

What came to my mind on a cat is the following:

On a monohull I usually do not really care about reefing. If the boat will turn into the wind because of extensive windpressure (don't know how this is called in short in english) .... well then I'll go with smaller sail size.

But that is different on a cat. The ability to be able to 'dose' windpressure continiously might come in very handy. Since I understood that a cat can capsize. Which is less probable on a monohull.

PS.: Need to train english sailing jargon....

[Jim Cate]

Originally Posted by Lost Horizons

The difference in weight only exists when motoring, and then the extra weight will act as a roll dampener.

Can't agree with this statement. When reefed, the rolled up head of the sail is still weight aloft. With slab reefing, the bunt of reefed sail is at the boom, many meters lower down.

Jim