Reefed sail proportions

[Tranona]

Does it actually matter? I'm not a student of fluid dynamics but I would doubt that the forces exerted are proportional to the sail area, or even easily predictable. Unless you have a continuous system such as a furling main, the reef is always going to be a bit too little or too much. All I need is a reef available for the strongest I am likely to be out in and either one or two reefs available for the intermediate blows, which may as well be evenly spaced for aesthetic reasons.

It is actually a furling mainsail that the OP is asking about which makes most of the suggestions largely irrelevant except post#2 which gives the suggested %age reduction in sail area at each reef - approx 20%, then 40% finally 55%.

As the OP points out when of the big advantages of a furling sail is that the area is infinitely variable so avoiding predetermined fixed sail area. However some people find it useful (as with furling genoas) to have markers on the foot that equate to the fixed areas of slab reefs (or in the case of foresails fixed types of sails - genoa, working jib No2 etc). Having had 2 boats with furling mainsails I never felt the need for this - if a reduction was too much, let a bit out, too kittle, wind a bit more in. I can however see the advantage if leaving the job of sail reduction to a crew member. "wind in until the first marker" is a simple instruction. However as a "usually) solo sailor I never felt the need for such an instruction to myself!

Now owning a boat with slab reefing I suppose I shall have to re-learn how to deal with the complication and live with the constraints of fixed mainsail sail areas, as well as how to get the best out of a twin headsail rig1

 

[jwilson]

In my opinion many AWB production boats from new "standard" mainsails come with too shallow reef points. Most AWBs benefit from reefing the main early and holding on to full or near-full genoa. Keeping the sailplan centre of effort forward also counteracts the tendency to "round up in gusts" often experienced once you get into conditions that require reefing.

When I replaced my AWB original mainsail I laid it out on the sailmaker's floor and marked out where I wanted the new sail's reef points to be - all significantly higher up the sail than the original. The "first reef" is now half-way between the original reef 1 and reef 2. Previously I was in the habit of going straight to reef 2 as reef 1 didn't do enough, and AWBs like to be sailed much flatter than my old long-keeled leadmine.

 

[West Coast]

I measured mine a while back, and as Tranona suggested, first reef reduces area by 20%, second takes reduction to 40% and third takes reduction to 55%. Mine is 44' AWB, with sail as provided with the original boat.

 

[Robih]

It is actually a furling mainsail that the OP is asking about which makes most of the suggestions largely irrelevant except post#2 which gives the suggested %age reduction in sail area at each reef - approx 20%, then 40% finally 55%.

As the OP points out when of the big advantages of a furling sail is that the area is infinitely variable so avoiding predetermined fixed sail area. However some people find it useful (as with furling genoas) to have markers on the foot that equate to the fixed areas of slab reefs (or in the case of foresails fixed types of sails - genoa, working jib No2 etc). Having had 2 boats with furling mainsails I never felt the need for this - if a reduction was too much, let a bit out, too kittle, wind a bit more in. I can however see the advantage if leaving the job of sail reduction to a crew member. "wind in until the first marker" is a simple instruction. However as a "usually) solo sailor I never felt the need for such an instruction to myself!

Now owning a boat with slab reefing I suppose I shall have to re-learn how to deal with the complication and live with the constraints of fixed mainsail sail areas, as well as how to get the best out of a twin headsail rig1

Tranona,

You’ve read my thinking well. The marks on the sail are merely indicative of the rough sail area deployed. If the wind has got up and I’m reefing (particularly the main) I don’t want to be fannying around whilst the sail flogs itself to death, I want a fast and certain indication of sail position so that I can tension the outhaul as quickly as possible. Fine adjustment can then be made under control.

I would add that reefing a furling main, Selden rig, is much easier on starboard than port. There’s no chance of reefing a furling main when on port, necessary to head up or tack. so for a controlled reefing manoeuvre in strong winds it’s never a case of just “wind a bit in“, not a chance.

From prompts above I made contact with the sailmaker again and asked for their guidance, to my great surprise I received a quick response. The guidance given accords closely with that kindly given in post #2.

 

[Daydream believer]

One of the few advantages of an inmast mainsail is the straight line from head to clew!

Really?

 

[Tranona]

Really?

Yes. Without battens there is nothing to support roach. That is the attraction of vertical battens in furling mains, although they are not without their problems. We decided against battens when designing the new sail for my Bavaria because Vectran is a bit bulkier than basic cloth and doubts about whether it would furl into the mast properly. Turned out correct as it was a tight fit. To get a stable and slightly shaped edge to the sail it was reinforced with Spectra. Worked well and a vast improvement on the basic sail that came with the boat.

 

[Chiara’s slave]

Anything would be an improvement on the usual hollow leeched in mast main. The bulk of vertical battens is a major impediment unless the system is designed for them from the outset. Our jib has them, it’s a lot fatter, rolled, than the previous sail. It’s not just the battens, it’s the pockets and straps too. A lot of bulk. With a jib you have all the space in the world, it’s just an observation. We do have a beautiful, even slot now, and the extra power in the jib is noticeable.

 

[Daydream believer]

Yes. Without battens there is nothing to support roach. That is the attraction of vertical battens in furling mains, although they are not without their problems. We decided against battens when designing the new sail for my Bavaria because Vectran is a bit bulkier than basic cloth and doubts about whether it would furl into the mast properly. Turned out correct as it was a tight fit. To get a stable and slightly shaped edge to the sail it was reinforced with Spectra. Worked well and a vast improvement on the basic sail that came with the boat.

I would have thought that a decent cut mainsail with decent battens & an acceptable roach, would be a big improvement, allowing a nice twist in the sail shape when sailing upwind

 

[Tranona]

I would have thought that a decent cut mainsail with decent battens & an acceptable roach, would be a big improvement, allowing a nice twist in the sail shape when sailing upwind

That may well be the case, but is physically impossible if you want to furl the sail vertically inside the mast.

Perhaps you have been asleep for the last 30 years as in mast furling has been around for a long time and thousands of boats and their owners seem to get around quite nicely without battened and roached sails.

 

[Supertramp]

I would add that reefing a furling main, Selden rig, is much easier on starboard than port. There’s no chance of reefing a furling main when on port, necessary to head up or tack. so for a controlled reefing manoeuvre in strong winds it’s never a case of just “wind a bit in“, not a chance.

Agree about starboard vs port and the need to get the wind out the sail to wind it in. I find that a close reach and letting the main out rather than heading into the wind takes the wind out enough to reef, and I can do it on port, albeit not as easily as starboard. The big plus is you can very easily let more sail out so I tend to over reef and let some back out if necessary rather than wondering about 2 vs 3 reefs. Plus when motorsailing or in gale conditions it is sometimes useful to set a trysail sized main.

On balance, I would prefer a conventional system but since the boat came with in mast and replacement will require a new mast, I concentrate on making best use of what I have and playing to the small number of benefits from in mast.

 

[Robih]

Agree about starboard vs port and the need to get the wind out the sail to wind it in. I find that a close reach and letting the main out rather than heading into the wind takes the wind out enough to reef, and I can do it on port, albeit not as easily as starboard. The big plus is you can very easily let more sail out so I tend to over reef and let some back out if necessary rather than wondering about 2 vs 3 reefs. Plus when motorsailing or in gale conditions it is sometimes useful to set a trysail sized main.

On balance, I would prefer a conventional system but since the boat came with in mast and replacement will require a new mast, I concentrate on making best use of what I have and playing to the small number of benefits from in mast.

Yes that about sums it up for me too, I always leave harbour assuming a gale and then unwind the over-prudent reefing when conditions outside the harbour wall are known.

 

[Chiara’s slave]

That may well be the case, but is physically impossible if you want to furl the sail vertically inside the mast.

Perhaps you have been asleep for the last 30 years as in mast furling has been around for a long time and thousands of boats and their owners seem to get around quite nicely without battened and roached sails.

For some, the convenience outweighs the major negative effect on the sailing qualities. I cringe when watching an OEM in mast main with it’s leech thrumming, attempting to push a sailing boat to windward. How anyone doesn’t tear their hair out with the old bedsheets you get with the boat I have no idea. I’ve seen a few decent looking aftermarket sails, but they’re still not a patch on a conventional slab reefed sail. I’ve not worked out why in boom reefing isn’t more popular.

 

[Fr J Hackett]

For some, the convenience outweighs the major negative effect on the sailing qualities. I cringe when watching an OEM in mast main with it’s leech thrumming, attempting to push a sailing boat to windward. How anyone doesn’t tear their hair out with the old bedsheets you get with the boat I have no idea. I’ve seen a few decent looking aftermarket sails, but they’re still not a patch on a conventional slab reefed sail. I’ve not worked out why in boom reefing isn’t more popular.

As I understand it in boom reefing is more sensitive to problems than in mast being particularly sensitive to boom angle which I think should be relatively easy to indicate. However the advantages of being able to drop a problematic sail for me would far outweigh any other disadvantages and like you I can see no reason why they aren't more popular as they can be made push button reefing if that's what is wanted either electrically or hydraulically.

 

[Daydream believer]

That may well be the case, but is physically impossible if you want to furl the sail vertically inside the mast.

Perhaps you have been asleep for the last 30 years as in mast furling has been around for a long time and thousands of boats and their owners seem to get around quite nicely without battened and roached sails.

Here is a quote from UK Halsey sailmakers
For decades, boats with in-mast furling mains have been sailing around with under performing sails. These hollow-roach sails are starved for power and the boats end up with leeward helm since the mainsail is too small to balance the genoa. BUT, there are a ton of them out there because in-mast roller-furling mains are convenient.
Now sailors with roller-furling mains can replace their poorly performing sails with a main that has positive roach supported by vertical leech battens – the UK-Halsey VB MAX Mainsail. The vertical partial-length battens are parallel to the luff so that the sail can be rolled into the mast.

Perhaps it is you that has been asleep. Technology has moved on. But of course some like to stay with out dated designs of sails ( & boats it seems) & if that suits them so beit. To each his own

 

[Supertramp]

For some, the convenience outweighs the major negative effect on the sailing qualities. I cringe when watching an OEM in mast main with it’s leech thrumming, attempting to push a sailing boat to windward. How anyone doesn’t tear their hair out with the old bedsheets you get with the boat I have no idea. I’ve seen a few decent looking aftermarket sails, but they’re still not a patch on a conventional slab reefed sail. I’ve not worked out why in boom reefing isn’t more popular.

You are right, but everyone sails different boats and in different ways. The choice of sails needs to match what and how you sail. I would prefer a 3 reef slab reefing system with stackpack but have Selden in mast. I suspect many people with 2nd hand boats will have the choice dictated by the original specification.

Its not a disaster - the sail sets satisfactorily up to about 45-50 degrees, is great off the wind and I avoid tacking unless helped by tide, plus the convenience is useful. I am adapting to it and it suits the boat, which is a steady passage maker often sailed singlehanded.


I race on a boat with a slab reef main and a roller furling genoa. The genoa part furled destroys the windward performance. Everything's a compromise!

 

[Tranona]

As I understand it in boom reefing is more sensitive to problems than in mast being particularly sensitive to boom angle which I think should be relatively easy to indicate. However the advantages of being able to drop a problematic sail for me would far outweigh any other disadvantages and like you I can see no reason why they aren't more popular as they can be made push button reefing if that's what is wanted either electrically or hydraulically.

They are with larger boats where the cost of engineering to make them work is less of an issue. Not popular in smaller sizes (sub 50' or so) in Europe because nobody serious makes them, unable to compete with the resources of Selden who have made their system pretty much idiot proof, low cost (£1200 extra on my £100k boat) and easy to sell to the typical new boat owner.

 

[Tranona]

Here is a quote from UK Halsey sailmakers
For decades, boats with in-mast furling mains have been sailing around with under performing sails. These hollow-roach sails are starved for power and the boats end up with leeward helm since the mainsail is too small to balance the genoa. BUT, there are a ton of them out there because in-mast roller-furling mains are convenient.
Now sailors with roller-furling mains can replace their poorly performing sails with a main that has positive roach supported by vertical leech battens – the UK-Halsey VB MAX Mainsail. The vertical partial-length battens are parallel to the luff so that the sail can be rolled into the mast.

Perhaps it is you that has been asleep. Technology has moved on. But of course some like to stay with out dated designs of sails ( & boats it seems) & if that suits them so beit. To each his own

No, I am wide awake and right up to speed having owned 2 boats with in mast and if you read what I wrote in post#26 vertical battens are not the perfect answer. In fact rather the opposite. I spent a lot of time and effort with more than one sailmaker finding a decent solution. All said battens were not the answer for my boat. Of course Halsey will give you the marketing puff by over exaggerating the problem and overselling the benefits of the product they are pushing. For a start as I will explain, not all boats are genoa driven as they imply. Just talk to the people who have had problems with furling, wear of the sail and the difficulty of getting the battens into the sail.

As ever, some work but a lot depends on the foot/luff ratio and therefore the amount of sail that needs to be furled. Tall, skinny mains are easier and benefit more from battens and the mast section is such that there is enough room to furl without snagging. My Bavaria 33, like a lot of newer boats has a large lower aspect mainsail and there simply is not enough room in the mast for battens. Kemps made the sail using Vectran (also recommended by the other 2 that I got quotes from). All are reluctant to use battens except on bigger boats with a mast section that will take them and owners who are prepared to pay the high cost (approx 35-40% more than unbattened).

As I said very happy with the sail in the short time I had it before I sold the boat.

I put just as much effort into researching and understanding what I am buying for my requirements as you do for yours - just different.

 

[Fr J Hackett]

They are with larger boats where the cost of engineering to make them work is less of an issue. Not popular in smaller sizes (sub 50' or so) in Europe because nobody serious makes them, unable to compete with the resources of Selden who have made their system pretty much idiot proof, low cost (£1200 extra on my £100k boat) and easy to sell to the typical new boat owner.

Furlerboom is a European manufacturer and its products are directly comparable with the US leisure furl whichh is probably the biggest and most popular manufacturer, you are right that it's around 50 foot that the economies begin to be less important and below that cannot come near the Seldon in mast system but they can be made if you are prepared to pay the cost and value the potential advantages.

 

[Daydream believer]

No, I am wide awake and right up to speed having owned 2 boats with in mast and if you read what I wrote in post#26 vertical battens are not the perfect answer. In fact rather the opposite.

I see that Elvstrom use full length battens on their Fatfurl main which also has a wide head
Here it is on a 34 ft Halberg. So not a particularly large craft either. I think they claim something like 15% more sail area & improved performance ( Well they would do) Must admit that I would not have in mast though. I do not even furl my jib, except to stowe it
Fatfurl

 

[Tranona]

I see that Elvstrom use full length battens on their Fatfurl main which also has a wide head
Here it is on a 34 ft Halberg. So not a particularly large craft either. I think they claim something like 15% more sail area & improved performance ( Well they would do) Must admit that I would not have in mast though. I do not even furl my jib, except to stowe it
Fatfurl

That will be enormously expensive and unlikely ever to get near the mass market. HR make maybe 20 of those boats a year (at a base price of £350k last time I looked!) of which perhaps 2 or 3 might choose that as an option.

A few years ago Doyle introduced a design that achieved the same result of greater area and a square(ish) top with a flip up batten to create the roach and support the head. Never caught on

That is how markets work. Producers try new ideas, often prompted by new materials and processes. Some work and become established, at least until the next better idea comes along, but most fail.

You have to recognise that for the vast majority of boat buyers, particularly of volume produced cruisers, sailing performance at the margins is not high on the list of priorities as for the type of cruising they plan to do the standard boat is plenty fast enough with minimum effort.

No different from those choosing basic slab reefing - few would want a boat that requires 14 bits of string to control the sails!