In mast furling - comments

[Magic_Sailor]

A couple of weeks ago I was lucky enough to be invited to sail in the Med with one of my little pals. He's yacht is equiped with in mast furling - the first time I'd used it.

The foot of the mainsail is not seated in the boom and I couldn't decide whether this improved or degraded the performance of the sail.

Any comments?

Magic

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[Aardee]

Hi Magic,

My understanding is that sail performance is reduced (you can't expect the additional convenience for nowt...).

I believe the main drawbacks are due to the lack of roach in a furling main, and the fact there are no horizontal battens to help the sail hold it's shape.

Not sure whether the unattached sail foot makes any difference...

Graham.

<hr width=100% size=1>"I am a bear of very little brain and long words bother me" - A A Milne.

 

[Talbot]

Re: In mast REEFING - comments

First - it is in mast reefing that you are discussing, because this system enables you to reef the sail as well as furling it (furling = stowing it away).

You will get a lot of contradictory comments on the ability of sails for in-mast reefing. My opinion (and I have changed from full length battens to an in-mast system) is that provided the sail is designed for the system, and had full vertical battens, there should be no real loss of perfomance. In fact in light airs, it may well be better, because you can achieve a better aerofoil shape with the loose footed sail. It does have two drawbacks.

The sailcloth is normally a lot lighter (but much higher quality) this helps the light wind ability, but means you have to reef a bit sooner than you might with a conventional main (but reefing is much easier).

If you dont have the mast/boom geometry correct, there is a good chance of getting a jam.

Overall, I am very pleaseed with mine, and especially when singlehanded reckon that it has much improved my fun.

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[irish]

Hi Magic

In addition to Graham's comments:

The main has to be cut quite flat in order that it can furl, this certainly degrades its performance.

Regarding sail battens, last year I spent a couple of weeks on a friend's yacht with in-mast furling, the sail had vertical battens which certainly helped keep its shape but from an aerodynamic viewpoint I'd have thought vertical battens were less favourable than horizontal battens

There are various other pros and cons of in-mast furling and I suspect these have been discussed many times. Personally I am a committed slab-reefing sailor however my opposition to in-mast furling is tending to soften as I sail various charter and friends boats which have it, particularly for short-handed sailing or with inexperienced crew. And for pottering around (say) the Ionian, what matters most - sail performance or ease of use ?

irish

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[Mirelle]

Loose foot is not a problem

Loose footed mainsails have been around for a century or three; they go in and out of vogue.

The increase in weight aloft degrades performance somewhat, and can be hazardous if fitted as an afterthought to boats which lack stability. The area is a bit less.

The thing that no-one has mentioned is the noise these things can make in a strong wind...

<hr width=100% size=1>Que scais-je?

 

[MrG]

We have Inmast reefing/furling and I would gladly convert to Slab main if it didn't mean replacing the mast.
Amongst the issues are the loss of 5 sq metres of sail compared to the non furling, the ability to jam at the slightest whim, lack of sailing ability, particularly to windward.

As for your question about loose footed - not sure it makes that much difference, I was out on a jeanneau 54 DS last week, it had slab main and loose foot and performed superbly...whether light airs or heavy wind..



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[doris]

Taller masts

The fact that certain manufacturuers have to increase the height of the mast to compensate for the loss of power proves the point. A friend with an Island packet reckons the only serious mistake he made was to have in mast furling. With modern single line slab reefing systems what possible reason can there be to compromise sailing performance to such an extent, to say nothing of the stability factor of the weight aloft.

<hr width=100% size=1>Real men do it 2handed.

 

[pessimist]

This had been retro-fitted to our boat when we bought it, so behind mast rather than in mast. The very flat sail shape was actually rather good going to windward but the lack of sail area and the considerable extra weight aloft persuaded us to remove it and revert to standard slab reefing with a stacking system. This is almost as easy to use, gives us back the lost sail area and is almost foolproof. I would never touch in mast/behind mast again.

<hr width=100% size=1>A pessimist is an optimist in full possession of the facts

 

[Iota]

I have a Hood Vertec in mast fitted, fully battened so you get a bigger roach. It has never jammed is a doddle to use all from the cockpit but.....The mast and sail were supplied new with the boat. The battens work well and the sail shape is also good. I probably to suffer a little in performance but not much and the benefit of ease of use outways any loss.

Iota

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[Ruthie]

Re: In mast furling - alternatives

I have a straight-forward slab reefing main. But I usually sail short handed, and have been pondering options to make life easier (I'm pretty much all for convenience!).

I'd pretty much rejected in-mast furling because of the expense of a retrofit, loss of performance and increased weight aloft... all the reasons discussed so far. (Tho' I get the impression that a loose foot might be worth having).

In-boom furling looks very appealing, though, again, not cheap. So I'm probably going to toddle along to Kemp for a stackpack and lazy jacks, and take it from there...

Ruthie

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[chuns]

There is an aspect of in-mast furling/reefing that is often ignored, and that is the ease of use of the system and flexibility this confers.

We often read of the when-should-I-reef dilemma, and that can mean that either the boat is reefed too late, resulting in excessive angles of heel, griping to windward, and loss of performance (and VMG); or, prudently reefing too early and being a bit under-canvassed.

On previous boats I have had conventional slab with and without full battens, plus single line reefing with stackaways led aft. For my (cruising) sailing the in-mast system wins hands down.

With a good modern properly designed system (and my current experience is of Selden on my boat) it is possible to readily make small adjustments to sail area thus having the optimum amount of sail deployed. I often say “I’m just going to take a couple of inches off the main” – this means the boat is kept more upright for longer and thus sailing at its best. And the same goes for when the wind dies – easy to increase area. This is done with little effort, not leaving the cockpit, and maintaining course.

Despite the loss of sail area compared to a roached sail, I think this optimisation issue means that in the longer run there is no material loss of passage making ability; and I seem to remember a test done by either PBO or YM where they compared two identical boats with conventional and in-mast and concluded the difference was small to insignificant.

I also think that when we consider these issues of shape and flatness we should remember that the total drive is a result of the main and genoa acting in concert, not as two separate sails. I believe (though I am not confident enough to be prescriptive) that, in the case of in-mast, this may lead to some slightly different sail tuning rules!


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[Rich_F]

I've just a couple of points to add.

With respect to in-boom furling...

I had it, and returned to slab reefing. I didn't like the excessively heavy boom, or the fact that it could easily jam up if the boom wasn't quite at the right angle.

And with respect to ease of use ensuring better sail trimming...

Very true - you'll be much happier shortening sail if it's easy. However, slab reefing is also easy - it's just that many people see it as a trial, probably because they don't practice much. My attitude to it changed a lot over the course of a windy few weeks in Scotland this year. The more times I reefed, the less it was an issue. I'd encourage slab-reefers to look for opportunities to practice reefing - it's good exercise, you'll probably sail better, and you'll be much less likely to be caught out with too much sail.

Rich

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[doris]

Stack pack??

So long as you do not have a bolt rope but sliders, and therefore the luff of the main remains captive when you drop it, all it takes is a bit of string for a lazy jack.

<hr width=100% size=1>Real men do it 2handed.

 

[Ruthie]

Re: Stack pack??

mmmm - bolt rope along th foot, sliders up the luff. Will go get me some string ;-)

Ruthie

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[DavidofMersea]

Why don't you find someone and do swap - What sort of boat do you have?

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[AOWYN]

When I needed to invest in a new main I felt the choice was between a fully battened system or retro-fit roller reefing. I went for EasyReef with vertical battens

I wanted more performance, but recognised that just taking the damned sail-cover off was becoming a chore when I only had a few hours boat use in a busy week, hence the choice of vertical reefing.

I know I have less power than a good fully battened system and the cost difference is minimal if you are going to have proper roller fitings on the mast-end of the battens, BUT, I use the main so much more, and I can adjust it so readily that overall I know I am doing more sailing and less motoring, so I am pleased with the decision.

As for any performance loss, the new rig gives better performance than the worn out old mainsail, even if less than a really good fully-battened sail, and in any case the weed which attached itself to the boat after only 7 weeks in the water is reducing performance far more than any factor arising from sail choice.

Conclusion: an antifouling that works would be better than a new mainsail.

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