In mast furling pros and cons

[richardh10]

I didn't want to hijack Robins thread so I thought I would ask in a new one for the pros and cons of in mast furling.

My initial thoughts are that its not a good idea, but I can't quite work out why I think that! Are there more things that can go wrong than with slab reefing? Have people had problems with it, or is it like many things, and once you've got used to it, you don't know how you ever lived without it.

As I hope to be changing my boat in the next 12 months, I wouldn't want to rule out a boat with in mast furling without good reason.

Any opinions welcome, good and bad!

Thanks

 

[pvb]

Assuming regular maintenance, in-mast furling works easily, effectively and reliably. I now wouldn't be without it. People will say that sail shape is compromised, which it is, but if I wanted to get somewhere quickly I'd have bought a mobo. There may be additional safety benefits, with all lines led aft, and no need to go on deck to stow the sail. And the fact that you can reef so easily encourages doing it early, rather than waiting. One other factor to bear in mind is that in-mast furling is now so increasingly popular that buying a cruising boat without it may lead to subsequent resale difficulties.

 

[Twister_Ken]

One con - weight aloft.

The weight of the sail, when partially reefed is in the mast and at x feet above the centre of gravity, where x can be quite a big number.

With slab reefing (or in-boom) the partially reefed weight is lower, in relation to the centre of gravity.

Thus, in-mast, when reefed, makes the boat a little more tender (more weight, further aloft).

 

[howard easton]

The resale price argument is a nonsense - there will always be people who prefer one or the other. I doubt the safety argument since all lines can be led aft with slab reefing. And in mast has the disadvantage of putting extra weight high up and reducing stability as a result. And yes sail shape is conpromised but then if that was a prime concern you would consider a boat without back stay and a flat topped sail. As for the "if I wanted to get somewher quickly" argument - just watch pvb start tweeking sails as you come along side him.

Its a personal preference. Roller furling genoas are standard now outside race boats so I dont see why roller furling mains should not be provided the yacht design is tailored for them. To my mind the only serious contra argument is the issue of jamming which is inevitable when the sail has to be furled into a container unlike the foresail. If you bunch the foresail no ptroblem. If you bunch a roller furling main then thats an issue. So personally I would go for a roller boom in preference

 

[davidej]

I think it is a bit of a size issue.

For boats smaller than, say, 35 ft, it is not necessary nor will you want the performance penalty.

Above that size, it is a great way of saving effort hauling-up or reefing a girt-great mainsail.

 

[pvb]

So personally I would go for a roller boom in preference

Many people seem to have had difficulties with roller booms, which is perhaps why there are so few of them around.

 

[pvb]

The resale price argument is a nonsense - there will always be people who prefer one or the other.

Not a nonsense at all. My point is that more people in the future are likely to demand in-mast furling on cruising boats. When I sold my boat earlier this year, the buyers had the choice of mine or a same-age same-condition boat with the advantage of a recently-fitted new engine. They chose mine, because it had in-mast furling, and paid £7K more than the alternative.

 

[PeterWright]

Twister Ken is, as usual, absolutely correct and in addition to the weight of the sail, there is the furling mandrel all the way up the mast. However, the equivalent weights (sail + mandrel) remain aloft on a furled up genoa, and few cruising yachtsmen would see that as a reason not to have a roller furling genoa.

The compromise in sail shape pvb refers to is a bit more complicated.It will, of course, be loose footed which, imho, is better than bolt rope foot anyway and, to allow it to roll up neatly, it will be a fairlty flat cut. If it has no battens, the leech will be concave (negative roach). Short vertical battens, designed not to overlap each other when furled, will support a straight leech (zero roach) and full height vertical battens will support a substantial roach, so you don't have to suffer a loss of sail area. However, concern about possible furling jams deterred us from full height battens, although many who have them report no problems.

pvb's point about regular maintenance is well made, and the system, like a headsail furler, requires more maintenance than a simple haul up and down main. Blown out (no longer flat) sails are another potential source of jams - a crease in the roll can jam (but not irretrievably, unless someone just keeps pulling at it) between the roll and the slot. The crew need to learn the right way to set, furl and reef with an in mast furler, just as they do with a more conventional system.

Like you, I used to be against the idea, until we started looking for our ideal cruising yacht for our senior years. On almost every count, the Moody 425 fitted our needs and budget the one issue, for me, was the in-mast furling main which was fitted as standard. We looked into changing to a stackpack system, but that would require a new mast which we ruled out on cost grounds, so we went for it anyway. We replaced the (knackered) sails in our first season of ownership and, 5 years on, like pvb, we wouldn't be without it.

If you have a boat designed for in-mast furling, the designer will have taken the weight aloft and the compromised sail shape into account, along with all the other compromises that make up the art of yacht design and her performance should be exactly as he intended.

One more little recognised advantage of on mast furling is that the Kemp/Selden extrusions for this system come with a ready made luff groove for a trysail - not everyone uses it, but it's good for those that do.

In summary, in-mast furling has no place on any yacht with aspirations as a racer, but, imho, is a boon on cruising yachts above around 35 foot, particularly if they're sailed short handed.

 

[doug748]

I'd be much happier above 35 feet loa. As Twister Ken has said, there is a weight penalty in poor conditions, and the mast itself will be heavier and the windage will be greater.

If you also have (perhaps on the grounds that it does not matter much) a radar arch, saildrive with fixed prop, sprayhood and bow thruster pretty soon you have designed yourself a motor sailor. Which is fine if that is what you need, otherwise maybe not.

 

[Tranona]

The extra weight aloft is vastly overstated. While it may be the case with "add on" systems it is not when the boat was designed to have in mast in the first place.

For many the convenience and simplicity of in mast outweighs any loss in performance, and indeed one of the major advantages is that it is much easier to adjust sail area to suit the conditions rather than being limited to only 3 (or maybe 4) fixed mainsail areas. In boom reefing may also offer similar advantages in flexibility, but despite several manufacturers offering them, they have never gained enough acceptance, partly because of cost, and partly because they seem to be less reliable in use, requiring care to operate, particularly the need to go head to wind to reef.

As to resale, if 50% of new owners have chosen in mast (which is roughly the proportion in recent years) then it is reasonable that 50% of used boat buyers are likely to prefer the same.

This subject comes up here regularly and if you go back over the threads you will have difficulty in finding an owner of an in mast boat that would change. It seems the only people who don't like it are those who have never owned a boat with it fitted!

 

[wully1]

Horses for courses..
for a cruising boat, why not?

Before my current boat I'd not even thought about ifurling mains and I managed to jam it the first time I used it. Since then- no problems.

you can get a main cut with more roach than old generation furling sails if you are worried about performance but as cruising sail boats have such rubbish shaped sails anyway this shouldn't worry you...
( IMHO only the top end race boats have anything like decent sail shapes and even they are dog slow compared to dinghies or especially windsurfers)

 

[dunedin]

The re-sale value point above will I suspect, like many thinks "depend" - particularly on the type of boat.

With a biggish AWB, perhaps oriented more towards cabin space and convenience, lack of a roller furler could really inhibit resale.
With a moderate sized, more sailing performance oriented cruiser, then a roller furler main could be a value destroyer. Can't imagine many lining up for a roller furler Arcona for example, at least below 45 feet or so.

 

[howard easton]

Not a nonsense at all. My point is that more people in the future are likely to demand in-mast furling on cruising boats. When I sold my boat earlier this year, the buyers had the choice of mine or a same-age same-condition boat with the advantage of a recently-fitted new engine. They chose mine, because it had in-mast furling, and paid £7K more than the alternative.

Illogical. Leaving aside that there would be other differences between the two boats, you are quoting the case of one buyer who maybe wanted in mast reefing and happily ignoring other buyers who didnt offer on your boat because they werent interested in in mast reefing. I would be a case in point. I would not consider buying a boat with in mast reefing just as I wouldnt consider one with teak decks.

The responses to this thread show you a fair number of people who would not consider in mast mainsail reefing. To some degree it depends on whether you want a boat as a floating caravan or as a performance machine - to exagerrate the difference a bit!

 

[mjcoon]

The extra weight aloft is vastly overstated. While it may be the case with "add on" systems it is not when the boat was designed to have in mast in the first place.

For many the convenience and simplicity of in mast outweighs any loss in performance, and indeed one of the major advantages is that it is much easier to adjust sail area to suit the conditions rather than being limited to only 3 (or maybe 4) fixed mainsail areas. In boom reefing may also offer similar advantages in flexibility, but despite several manufacturers offering them, they have never gained enough acceptance, partly because of cost, and partly because they seem to be less reliable in use, requiring care to operate, particularly the need to go head to wind to reef.

As to resale, if 50% of new owners have chosen in mast (which is roughly the proportion in recent years) then it is reasonable that 50% of used boat buyers are likely to prefer the same.

This subject comes up here regularly and if you go back over the threads you will have difficulty in finding an owner of an in mast boat that would change. It seems the only people who don't like it are those who have never owned a boat with it fitted!

I think the issue of a limited number of reefing areas is a good one. So many boats have only two sets of reefing lines rigged, especially with single line reefing. With in-mast reefing you can go down to such a small area that hopefully the fact that it is not a heavy storm sail hardly matters...

Mike.

 

[pvb]

The responses to this thread show you a fair number of people who would not consider in mast mainsail reefing. To some degree it depends on whether you want a boat as a floating caravan or as a performance machine - to exagerrate the difference a bit!

There are usually a lot of floating caravans crossing the Atlantic then!

 

[PeterWright]

the mast itself will be heavier and the windage will be greater.

An in-mast furling mast is made from a very different extrusion from a normal mast. The most common design (Kemp/Selden) is properly engineered so that the features required for in-mast furling contribute to the spars stiffness, so replacing the stiffening features found in a normal design. The overall section remains the same. As such, I very much doubt that either the weight or the windage if the mast is any greater in the in-mast furling version. As I wrote earlier, additional weight aloft is the furling mandrel, which is very similar to the mandrel on a genoa furler and the sail itself.

 

[silver-fox]

Twister Ken is, as usual, absolutely correct and in addition to the weight of the sail, there is the furling mandrel all the way up the mast. However, the equivalent weights (sail + mandrel) remain aloft on a furled up genoa, and few cruising yachtsmen would see that as a reason not to have a roller furling genoa.

The compromise in sail shape pvb refers to is a bit more complicated.It will, of course, be loose footed which, imho, is better than bolt rope foot anyway and, to allow it to roll up neatly, it will be a fairlty flat cut. If it has no battens, the leech will be concave (negative roach). Short vertical battens, designed not to overlap each other when furled, will support a straight leech (zero roach) and full height vertical battens will support a substantial roach, so you don't have to suffer a loss of sail area. However, concern about possible furling jams deterred us from full height battens, although many who have them report no problems.

pvb's point about regular maintenance is well made, and the system, like a headsail furler, requires more maintenance than a simple haul up and down main. Blown out (no longer flat) sails are another potential source of jams - a crease in the roll can jam (but not irretrievably, unless someone just keeps pulling at it) between the roll and the slot. The crew need to learn the right way to set, furl and reef with an in mast furler, just as they do with a more conventional system.

Like you, I used to be against the idea, until we started looking for our ideal cruising yacht for our senior years. On almost every count, the Moody 425 fitted our needs and budget the one issue, for me, was the in-mast furling main which was fitted as standard. We looked into changing to a stackpack system, but that would require a new mast which we ruled out on cost grounds, so we went for it anyway. We replaced the (knackered) sails in our first season of ownership and, 5 years on, like pvb, we wouldn't be without it.

If you have a boat designed for in-mast furling, the designer will have taken the weight aloft and the compromised sail shape into account, along with all the other compromises that make up the art of yacht design and her performance should be exactly as he intended.

One more little recognised advantage of on mast furling is that the Kemp/Selden extrusions for this system come with a ready made luff groove for a trysail - not everyone uses it, but it's good for those that do.

In summary, in-mast furling has no place on any yacht with aspirations as a racer, but, imho, is a boon on cruising yachts above around 35 foot, particularly if they're sailed short handed.

Great summary. Love in mast reefing, love my Moody 425, wouldn't change after thousands of cruising miles. I am always surprised by the number of people that are deeply critical of in-mast reefing but endorse roller reefing genoas with many of the same design features.

 

[NormanS]

Apart from the very easy foot tension adjustment, the better air flow with a loose footed sail, and the ease of reducing sail area to exactly what is required, and the fact that you only have to hoist the sail once a year, no obvious advantages.

 

[Norman_E]

Apart from the very easy foot tension adjustment, the better air flow with a loose footed sail, and the ease of reducing sail area to exactly what is required, and the fact that you only have to hoist the sail once a year, no obvious advantages.

I must confess that it would be easier than my full battened main sail on a 45 footer, but I do wonder that so many people seem to think that the traditional sail is so much harder work. I am in my late 60's, not very big or strong and have a damaged left arm with very little strength yet I sail the boat single handed and the hardest job with the mainsail is actually zipping up the rather tight sailbag.

 

[ANDY123]

you can always cut a halyard in an emergency, where an in mast reeling system jammed up is a different matter