In mast-v-slab reefing

Slow_boat

Slow_boat

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Why is in mast reefing so good? It always strikes me to be over complicated, expensive, liable to jambing, needs a smaller sail with no battens and no roach and unlikely to maintain its shape as it's reefed. Maybe my view is coloured by having one spit bearings all over the place when I needed it.

Slab reefing is simple, less to go wrong, easy to pull in, sail retains its shape and can have as many battens and as much roach as you want. And it's cheap.

So what's so good about in mast reefing?
 
Like you, I was the original sceptic on in mast furling as I was with rolling genoa once. I now have a boat which came with inmast furling and I nearly didn't by it because of it.

Now I have it, it is absolutley ideal for Husband and wife (40 foot) and is SO easy to furl, (less effort than slab by a long way) that I am prepared to put up with the down side, which are generally less performance, and slighlty worse pointing. Once the wind is about 10knots true (15 over deck), the differences are really not so apparent, other than the effect on pointing. I cannot quantify how much the pointing is worse, as this year I have bought a 110% genoa and the pointing has improved considerably

I suppose the great thing is that reefing is just so simple, you take the trouble to reef when you need it rather than hang for that bit longer!

OK I am concerned that it may spew its ball bearings out, but I do check the components each year, and I might replace the top swivel next year....... after 17 years. but it certainly runs as smoothly as new.
 
If you are thinking about reefing, reef! If you are thinking about shaking the reef out, give it half an hour!

Much easier to make the decision to reef with in mast furling. If you shake it out too early, easy to put it back in.

Single or double handed, makes life much easier.
 
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So what's so good about in mast reefing?

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1 - In typical coastal cruising a short handed crew is likely to get their main set earlier and furled later at each end of a trip. Over a season this could equate to 5% to 10% less engine time.

2 - In light conditions the instant set of in-mast is likely to persuade a crew to unfurl and play with a new wind pattern after a period of motoring.

3 - In harbour, I reckon 15 minutes less prep and tidy up time per trip.

4 - No flappy stack-pack to obscure the helmsman's view under sail.

5 - No large expanse of stack-pack canvas degrading on a predictable 10 year service life.

6 - Less bits of string in the air.

7 - Easier to sling a boom tent over a naked boom.

8 - No need to go on deck at 3am to frap the lazy jack lines tapping on mast.

9 - Less domestic arguments with swmbo when she is accused of hiding the stack pack bonnet.

10 - Better overall boat speed each season as simple reefing adjustment promotes optimal set area.
 
My only exposure to an in-mast furling main was a SO35 on a flotilla holiday. In spite of constant (ab)use, it worked well and made life extremely easy. There was one slightly uneasy moment, whilst reducing sail in an acceleration zone between a couple of islands, when I thought it had stuck - but it hadn't.

Constant maintenance is a must, and I wouldn't fit it to a racer for all the reasons outlined on here over the years, but for short handed cruising when you're not in a hurry, it seems like les genoux d'abeille to me.
 
I'm a fence sitter on this one but I do know of two boats that lost their mainsail when the sail jammed in the in-mast tube. So I don't think that either system is totally foolproof.

We're still in the ice age with mast based slab reefing but am seriously considering getting all of the lines led back and beefing up the winches. Ano domini, etc.
 
On the down side, I have come across boats that have had a jam in heavy weather (true, it can happen with slab reefing, e.g. if the halliard jumps its sheave). A badly-setting in-mast sail seems to be a lot worse than a poor slab-reefed sail.

They lose area and may set poorly if they have no battens or be more prone to jamming if they have.

BUT - the ease of winding in a couple of turns when you're on your own during a night watch makes up for a lot.

With slab reefing you either have to go on deck or use a remote system that's at least as complicated and jam-prone as the in-mast type.

I would say on balance the in-mast has the edge, as long as the gear and the sail are top quality.
 
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8 - No need to go on deck at 3am to frap the lazy jack lines tapping on mast.

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My lazy jack lines are nowhere near the mast - they go from mid (lower) spreaders to the stackpack ...
 
Is this something where size matters? My GibSea 92, 31' of mid eighties French design has a 135% Genoa and a skinny little main. For me, a furling genoa is an absolute must but I'm OK with slab reefing on the main. I could see why I might want the alternative with a bigger main, purely for setting/reefing purposes, whilst the storage/absence of lines features of in-mast are attractive anyway.

Does anybody have any experience of retro-fit/behind the mast furling?

Mark
 
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Is this something where size matters? My GibSea 92, 31' of mid eighties French design has a 135% Genoa and a skinny little main.

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I agree this is a big deciding factor. My boat is 35ft but has a 400 sq ft main which puts me in 40 footer territory. The total effort for raising the main is equivalent to a 15 minute gym session plus 5 minutes of yoga.
 
Do not go there. They have just about disappeared from the market. Many of the horror stories relate to them rather than purpose designed masts.. Most serious failing is adding weight aloft on a boat not designed to take it. Also significant loss of area and mechanical inefficiencies.
 
I have in mast reefing. I didn't especially choose it but the boat I was interested in had it. My observations are as follows.

1. I am a single parent and sail with my two relatively inexperienced kids. It's less hassle than slab, leading to reefs being added and removed much more often. In marginal conditions having an infinitely variable sail plan means you can make the main just a tad smaller if needed. In very heavy conditions you can roll it almost totally away to the equivalent of third reef (or even further). We had 45kt over the deck last November and were able to reef progressively down, till the boat was settled, without drama.

2. When I got the boat, it was a right bitch to unfurl (furling was easy). I read several pages on sites about having to get the topping lift/vang/outhaul tensions right. It seemed those pages forgot about having the moon in the right quarter too. However, over the winter I 'invested' in two cans of Sailkote. Washed the sail then sprayed a can on each side of the sail. A few squirts on the outhaul car and the furling line blocks and now furling/unfurling is absolutely straightforward. Really, truly, a pleasure.

3. The main lacks a roach. I've been contemplating a vertical battened main to overcome this, and have had some very strong recommendations. However, on my boat much of the power comes from the 140% genoa rather than the main. I'm not sure how much difference it would make except in light winds. I have a cruising chute and kite which deals with off-wind performance in light airs anyway.

I would say that it's not a perfect solution, in my position it's helpful but a well set up slab system, with single line reefing would come close to being as adjustable. Next boat I wouldn't worry whether it had it or not but I'm not in a hurry to get rid of it either.
 
Thanks for your thoughts. Your comments about getting the tension right are quite germain in that the boats I referred to had slackened their main halyards which led to a kink in the sail on the way in, jamming and a subsequent loss of sail. Both the skippers were experienced guys and hadn't realised that such a small change to the sail plan could have such a catestrophic outcome. Hence it is not for me, I'm no mechanical marvel and need the systems on the boat to be fixable with a knife, a spanner and a Birmingham screwdriver.

The reality for us is that we won't be changing the boat, not before I retire from sailing anyway, and the only cost effective solution will be to lead the lines back for some kind of single line reefing system.
 
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My lazy jack lines are nowhere near the mast - they go from mid (lower) spreaders to the stackpack ...

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Good point, this is something I want to investigate further. Do you have a quick adjustment fitting at the forward stackpack/lazy line connection?
 
Yer! That's about right. Depends on the boat too. I have only a little one (boom that is!) but a gert big high mast. I can stow it in seconds from inside me wheelhouse even if I am on a reach if I'm careful and don't need to go outside in the nasty rain and weather. If I had a proper sail I would have to take it all down and tie it up and have a cover to put on and and..... I would probably spill me drink and get wet!! Yuk.....
 
yup - they're tied off in a knot on the furthest forward connection to the pack - the pack has a pocket each side for the excess line - but why do you need to adjust? I haven't done so yet ... once they are set up the main just falls into the bag ...
 
I'm installing luff reefing from the cockpit. A couple of extra bits of string but no going forward and no great expense or modification. The main aim is to make it easier/safer when single-handed and not to make the admiral nervous when I go forward and leave her in the cockpit.
 
Just helped bring a new H-R40 back from the yard in Sweden. It had the Selden in-mast furling system but with the controls at the mast. Had the outhaul been back to the cockpit then things would have been much easier.
Sail had been loosely furled in yard and kept jamming when we tried to pull it out so need to have some tension on it when furling.
Horrid looking sail - ok, am used to my J-109 now, but even so i can now see why the Swedes say " When does a H-R have its sails up? - Only when the engine fails!"
 
I'm liking my fully battened slab reef main ... although only put 1 reef in so far ... haven't needed any more than that!! /forums/images/graemlins/smile.gif
 
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