In mast furling vs slab reefing

[Tranona]

Surely the weight of the sail is not the whole picture. The additional size of the mast, and the mechanism itself would be a chunk of the additional weight up there.

No, it is rather the opposite. Generally the sections of furling masts are smaller and lighter than than non furling. The stability calculations are exactly the same. There is confusion here between adding in mast to a rig that was not designed for it and one that was. Do you think that designers do not know or understand how to design boats and rigs?

I was asking for calculations of stability not observations of 2 different boats or as in post#54 a side by side comparison.

 

[Tranona]

I have sailed two boats with Furlboom in boom reefing and they were OK but the angle of the boom was important if not critical when reefing. The sails imo did not set as well as a slab reef of which I have saile more than a few. Not sailed an in mast so anything I say is purely speculative and fueled by my prejudice, I wouldn’t want it on my boat. IMO a well cut single line reefing main with lines led back to the cockpit is unbeatable, there is no reason that it can’t be handled by a single hand sailor, I have on boats up to a 50 foot Valiant.

Well its like oysters (the shellfish not the boats)- you don't know if you like them until you try them. Of course if you were wealthy enough to afford a modern oyster it (like almost all similar ocean cruising boats) will come with in mast furling, or maybe on the larger sizes with in boom. Lots of very knowledgeable and satisfied owners. If your much vaunted single line reefing really was so good, why do you think buyers do not specify it?

So, yes purely speculation on your part. Come back into the discussion when you have experience of both (like me). Not that you (or anybody else) necessarily have to agree with me but at least you will be able to engage on the basis of personal experience.

 

[Kelpie]

No, it is rather the opposite. Generally the sections of furling masts are smaller and lighter than than non furling.

I'm not saying that's untrue but it's certainly counterintuitive.
Why would an in-mast section, which has to be larger to accommodate the sail and foil, plus of course the foil, furler, etc, end up being lighter than a basic may designed for slab reefing?

 

[Chiara’s slave]

No, it is rather the opposite. Generally the sections of furling masts are smaller and lighter than than non furling. The stability calculations are exactly the same. There is confusion here between adding in mast to a rig that was not designed for it and one that was. Do you think that designers do not know or understand how to design boats and rigs?

I was asking for calculations of stability not observations of 2 different boats or as in post#54 a side by side comparison.

I have every faith in designers. If you are right, and I’m certainly not saying you’re wrong, fair enough. But designers make compromises in every single decision they make. And in mast furling looks, from a non user perspective, like every compromise I would refuse to make.

 

[Fr J Hackett]

Well its like oysters (the shellfish not the boats)- you don't know if you like them until you try them. Of course if you were wealthy enough to afford a modern oyster it (like almost all similar ocean cruising boats) will come with in mast furling, or maybe on the larger sizes with in boom. Lots of very knowledgeable and satisfied owners. If your much vaunted single line reefing really was so good, why do you think buyers do not specify it?

So, yes purely speculation on your part. Come back into the discussion when you have experience of both (like me). Not that you (or anybody else) necessarily have to agree with me but at least you will be able to engage on the basis of personal experience.

Some do specify slab reefing I think a lot of people associate slab reefing with going to the mast and are concerned or even frightened about it that or they think it’s hard work. Having experienced in boom reefing ( expensive systems on large boats with no real problems other than ensuring the boom was at the correct angle I still wouldn’t choose it over slab reefing but if I had to make the choice between it and in mast it would be in boom which would have all of the perceived advantages whilst being able to be dropped if needs must.

 

[Clancy Moped]

No, it is rather the opposite. Generally the sections of furling masts are smaller and lighter than than non furling. The stability calculations are exactly the same. There is confusion here between adding in mast to a rig that was not designed for it and one that was. Do you think that designers do not know or understand how to design boats and rigs?

I was asking for calculations of stability not observations of 2 different boats or as in post#54 a side by side comparison.

How would you gather these calculations?

 

[Koeketiene]

Some do specify slab reefing I think a lot of people associate slab reefing with going to the mast and are concerned or even frightened about it that or they think it’s hard work. Having experienced in boom reefing ( expensive systems on large boats with no real problems other than ensuring the boom was at the correct angle I still wouldn’t choose it over slab reefing but if I had to make the choice between it and in mast it would be in boom which would have all of the perceived advantages whilst being able to be dropped if needs must.

All my boats have had slab reefing.
My first one with single line reefing and all led back to the cockpit, the two subsequent ones with halyards/reefing lines at the mast.
I was a bit aprehensive at first, but I now actually prefer having all lines at the mast (even when sailing singlehanded).
The only thing I added was a selftailing winch on the mast.
IMHO, the less complicated a system, the less likely it is to go wrong.

 

[Tranona]

I'm not saying that's untrue but it's certainly counterintuitive.
Why would an in-mast section, which has to be larger to accommodate the sail and foil, plus of course the foil, furler, etc, end up being lighter than a basic may designed for slab reefing?

The mast section on my Bavaria 33 was smaller and lighter than the conventional version.

The issue raised was about a boat with in mast rolling more at anchor - but the example given was both subjective and compared two different designs of boats, not side by side comparisons.

Seeing the designers stability curves of the with/without would give a guide as to any differences and I have not seen such data published.

There does not seem to be any evidence that in mast furling boats capsize more often - not that many boats do at all. The "myth" - I say that because there is no real evidence - that in mast seriously reduces stability comes from an article nearly 30 years ago which gave as an example a boat that already had low stability being converted to add on in mast and furling jib allegedly failed its stability test for coding. This is very different from more recent boat designs which have such "extras" as standard and are subject to more rigorous stability calculations.

I am never sure why people get so worked up about this supposed loss in stability but carry on adding raydomes and radar reflectors high up on masts and huge arrays of solar panels on gantries, bimins etc all of which have a negative effect on stability.

 

[Koeketiene]

I am never sure why people get so worked up about this supposed loss in stability but carry on adding raydomes and radar reflectors high up on masts and huge arrays of solar panels on gantries, bimins etc all of which have a negative effect on stability.

Solar panels on gantries and biminis could/will possibly affect windage, but being low down I don't see how they could/would affect stability much.

 

[Clancy Moped]

The mast section on my Bavaria 33 was smaller and lighter than the conventional version.

The issue raised was about a boat with in mast rolling more at anchor - but the example given was both subjective and compared two different designs of boats, not side by side comparisons.

Seeing the designers stability curves of the with/without would give a guide as to any differences and I have not seen such data published.

There does not seem to be any evidence that in mast furling boats capsize more often - not that many boats do at all. The "myth" - I say that because there is no real evidence - that in mast seriously reduces stability comes from an article nearly 30 years ago which gave as an example a boat that already had low stability being converted to add on in mast and furling jib allegedly failed its stability test for coding. This is very different from more recent boat designs which have such "extras" as standard and are subject to more rigorous stability calculations.

I am never sure why people get so worked up about this supposed loss in stability but carry on adding raydomes and radar reflectors high up on masts and huge arrays of solar panels on gantries, bimins etc all of which have a negative effect on stability.

Do you have any calculations to support this statement?

 

[Tranona]

Some do specify slab reefing I think a lot of people associate slab reefing with going to the mast and are concerned or even frightened about it that or they think it’s hard work. Having experienced in boom reefing ( expensive systems on large boats with no real problems other than ensuring the boom was at the correct angle I still wouldn’t choose it over slab reefing but if I had to make the choice between it and in mast it would be in boom which would have all of the perceived advantages whilst being able to be dropped if needs must.

Reefing at the cockpit has been almost universal now on production boats for getting on for 30 years.

I simply do not buy this "simplicity" bit attached to slab reefing. Miles of string, blocks friction, hidden mechanism if in boom and more importantly limited choice of sail areas (plus swathes of unused sailcloth dangling around the boom when reefed. Compare this with just 2 control lines to give you an infinitely variable sail area and all unused sailcloth tucked away. I know that most in mast are less efficient as foils and may have smaller area, but this does not need to be the case and in reality for cruising boats has little impact on passage times while making life easier for the crew.

Bigger boats may specify slab reefing if they have a big crew, but having it is one of the major factors in making boats like the Oysters, bigger HRs, Discovery etc suitable for middle aged husband and wife crews. The changeover point in size is around 12m where the effort required to deal with slab reefed mains on modern boats starts to become too much for single or shorthanded crew. Just look on Yachtworld at the HRs for sale and you will see 90% or so of the boats above the 36/37 have in mast. Are all the original owners ignorant and don't know what they are doing when they specify in mast? Almost certainly most will have sailed and owned boats with slab reefing so know what they are "losing".

People construct arguments to support what they do (or have) rejecting alternatives of which they have no experience. Those of us who have experience of both systems (in this case) are, I would suggest both in a better position to make comparisons and make informed choices. Just so there is no misunderstanding, I was wary of in mast having listened to all the naysayers 25 years ago until I bought my first one. I made the choice because it was for a Med charter boat and it was a good choice, working faultlessly for the 14 years I owned the boat. not surprisingly I did the same for my new Bavaria which was specified to make it easy for me in my mid 70s to single hand. Only mistake I made was not specifying the better sails, although I did change after 4 years.

Now of course I am back with slab reefing with my project boat which is a reminder of why I rejected it when I had the choice.

 

[Tranona]

Solar panels on gantries and biminis could/will possibly affect windage, but being low down I don't see how they could/would affect stability much.

You would be surprised. Look at how far they are above the COG, and how heavy gantries in particular are. some also add a wind turbine and raydome on a pole!

 

[doug748]

The mast section on my Bavaria 33 was smaller and lighter than the conventional version.....

How do you know this?

 

[Chiara’s slave]

The mast section on my Bavaria 33 was smaller and lighter than the conventional version.

The issue raised was about a boat with in mast rolling more at anchor - but the example given was both subjective and compared two different designs of boats, not side by side comparisons.

Seeing the designers stability curves of the with/without would give a guide as to any differences and I have not seen such data published.

There does not seem to be any evidence that in mast furling boats capsize more often - not that many boats do at all. The "myth" - I say that because there is no real evidence - that in mast seriously reduces stability comes from an article nearly 30 years ago which gave as an example a boat that already had low stability being converted to add on in mast and furling jib allegedly failed its stability test for coding. This is very different from more recent boat designs which have such "extras" as standard and are subject to more rigorous stability calculations.

I am never sure why people get so worked up about this supposed loss in stability but carry on adding raydomes and radar reflectors high up on masts and huge arrays of solar panels on gantries, bimins etc all of which have a negative effect on stability.

I don’t think they have any serious effect on ultimate stability. All that has been suggested is that any extra weight would make a contribution to rolling at anchor. Which, if there were any additional weight, would be true. You’re right about solar panels and radomes mounted high up of course. We don’t, and never will, have radar, the overall weight and windage is unacceptable to us. We don’t need an arch for solar, we have acres of deck space on the floats as well as the main hull. We also have a carbon rig, hence my recoiling in horror at the mere thought of extra weight aloft.

 

[Kelpie]

How do you know this?

Maybe it was a shorter rig?? I see no reason why a conventional mast would ever be heavier than one designed for in-mast furling.

 

[Chiara’s slave]

Maybe it was a shorter rig?? I see no reason why a conventional mast would ever be heavier than one designed for in-mast furling.

It does fly in the face of logic. Unless it was quite old hat, and had one of those ghastly hollow leaches they used to have and therefore could have a much lighter section owing to the patheticness of the sail area

 

[Fr J Hackett]

All my boats have had slab reefing.
My first one with single line reefing and all led back to the cockpit, the two subsequent ones with halyards/reefing lines at the mast.
I was a bit aprehensive at first, but I now actually prefer having all lines at the mast (even when sailing singlehanded).
The only thing I added was a selftailing winch on the mast.
IMHO, the less complicated a system, the less likely it is to go wrong.

All my own boats were slab reefed the last two with single line back to the cockpit which I found easy and certainly not arduous. At the mast or cockpit once you get a stable platform which depends on the boat is not really an issue. On the larger boats I have sailed some on reasonably long passages powered winches have been useful. Even now were I to specify a new 50 foot boat it would be slab single line back to the cockpit with a powered winch.

 

[Chiara’s slave]

My F27, the kind of boat Rummy had, had on boom reefing. Being a tri, going to the mast wasn’t much of a challenge, hard boat to fall off. It had a crank handle. You took the clutch off the main halyard, put your foot on the rope for friction and wound the sail round the boom. Effective, tidy, simple, and worked with full battens.

 

[Kelpie]

I simply do not buy this "simplicity" bit attached to slab reefing. Miles of string, blocks friction, hidden mechanism if in boom and more importantly limited choice of sail areas (plus swathes of unused sailcloth dangling around the boom when reefed. Compare this with just 2 control lines to give you an infinitely variable sail area and all unused sailcloth tucked away.

"Everything should be as simple as possible, but not simpler"- Einstein (allegedly).
Boiling down the reefing system to two lines certainly sounds simple. In the same way that running everything to a single winch via banks of clutches 'looks' simple.
I know boats differ, but my own experience of in-mast was that it required the boom to be perfectly level and the boat to be very close to the wind, far more so than with slab reefed boats I've sailed. So the setup is simple but the operation itself has extra complications. Some people even use the engine every time they reef, just to keep the boat head to wind enough. I presume that's a particularly badly set up example and hope that your experience is better.

Those of us who have experience of both systems (in this case) are, I would suggest both in a better position to make comparisons and make informed choices.

You're not the only person who has experienced both.
I don't have extensive experience of in-mast, but the boat I did my day skipper on had it, and I later skippered that boat for another trip around the North Minch for a few days. I've also had to climb a mast to help out an elderly cruiser whose in-mast system had failed, hundreds of miles from home, which left an impression on me.

When it comes to lines led aft, I've had both systems. Led aft works if you have enough space in the cockpit for the lines, and if you have good quality (ballraced) blocks, good lead angles to winches/clutches etc.
We currently have everything at the mast and I have no plans to change. As someone said upthread, a self tailer at the mast is a useful upgrade, because it gives you a hand to hold on with. Reefing at the mast is my idea of 'simple'.

 

[Chiara’s slave]

Bearing in mind this is the liveaboard section, slab reefing at the mast has it's attractions for medium /large self reliant boats.