In-mast vs in-boom furling

[Paul L]

Question about in-mast systems. Do you have any mast bend control with them?

[Kenomac]

Originally Posted by Paul L

Question about in-mast systems. Do you have any mast bend control with them?

Yes, we have a backstay tensioner which provides a surprising amount of bend in the mast. Ours is a Hood in-mast furling system, so I can only answer for what we have and don’t know about the others.

The rearward bend is quite noticeable.

[Pete7]

Originally Posted by Paul L

Question about in-mast systems. Do you have any mast bend control with them?

Not on our older Selden system, but the boat is a 1980s design with large masthead Genoa and smaller main.

Originally Posted by daletournier

What if the different experiences are based on the different imast furlers that ones used?

I like mine alot ,this is due to I've had no problems regarding jamming. I was just on a Beneteau 44 center cockpit , I do not know what year. The owner hates his inmast, it jams regularly. It's a older Seldon rig and has a very narrow slot ,lucky to be 10mm. I looked at it and can easily see why he hates it.

The slot on my Sparcraft rig is approximately 25mm, my mates newer seldon rig also has a slot approximately 25mm wide, both of us have had no problems and both like inmast furling. The other guy hates inmast furling.

That's quite a narrow slot. Our mast is 45ft so quite short, but the slot is probably 20-25mm. I will measure it at the weekend.

Pete

[Dockhead]

Originally Posted by captainwoody

. . . The concept of having to fire up the motor and turn into the wind to reef is ridiculous. No sailshape control? There are a bunch more reasons why inmast is bad offshore.

What? Turn into the wind to reef? No shape control? Never heard of an outhaul? Or a vang? It is obvious that you know exactly zero about in-mast furling.


Wise clients of such delivery "captains" don't let them TOUCH the rig, whatever type it may be, and make sure they motor the whole way.

[nilespf]

Originally Posted by Paul L

Question about in-mast systems. Do you have any mast bend control with them?

Making sure we are talking about bending vs raking. The sail cavity extrusion diameter vs the furled sail diameter clearances can allow some pre bending. The clearance is a function of outhaul tension, point of sail when furled, condition of sail and boom position. Raking of the stick is not an issue. When the rig was initially set up, if the rigger added pre bending to either tension the fore and aft stays or control mast pumping, hope that it wasn't too much. Mine has a bit of prebend but mostly due to tension in the baby stay. I would prefer no bending therby increasing sail/extrusion cavity clearances but not worth it to re rig.

If the question was on the fly bending as in racing I do not know of any In-Mast design in which the furler is captured at the top thereby allowing a prebend to actually effect the sail profile. The furler floats in the extrusion


Hope this is what you were asking.

[nilespf]

Originally Posted by Paul L

Question about in-mast systems. Do you have any mast bend control with them?

Just to make sure I'm not misleading anyone:
Prebending (as a consequence of mechanical design of the furler) cannot effect the shape of the deployed sail. Prebending will (if taken to an extreme) can/will/may actually reduce cavity clearances effectively reducing the usable life of the sail. I have a bit of prebend in my rig and in spite of that have been able to still use the sail vintage 2002. The foresail has long ago been replaced.



Trying not to confuse things

[Dockhead]

Originally Posted by Paul L

Question about in-mast systems. Do you have any mast bend control with them?

Selden system - very rigid mast and no bending. This is a disadvantage of this system. But you have really good control of foot and leech tension via vang and outhaul, and as a bonus, the outhaul control is not impeded when the sail is reefed.

[wingssail]

Originally Posted by nilespf

In boom is safer than inmast. If the wind pipes up with inmast, it will not furl ... just when you need it the most. Inboom can at least be dumped on the deck when it fails.

But this should be practiced!

I practice it every time I come back from sailing!

[Paul L]

Originally Posted by Dockhead

Selden system - very rigid mast and no bending. This is a disadvantage of this system. But you have really good control of foot and leech tension via vang and outhaul, and as a bonus, the outhaul control is not impeded when the sail is reefed.

I was just wondering, as I only have one offshore passage experience with in-mast furling. While cruising I primarily use the back stay tension to tightened up the headsail when beating in higher winds. Vang is enough to control the main sail.

[Kenomac]

Originally Posted by Dockhead

Selden system - very rigid mast and no bending. This is a disadvantage of this system. But you have really good control of foot and leech tension via vang and outhaul, and as a bonus, the outhaul control is not impeded when the sail is reefed.

I’m surprised your mast doesn’t bend, our Hood masts both have a very pronounced bend which can be easily adjusted via the backstay tensioner. The bend doesn’t effect the electric furling in any way.

Have you tried tensioning your backstay? Can you have a rigger adjust everything to allow for bend?

[gonesail]

Originally Posted by mikedefieslife

Where is the evidence that in-mast furling gets jammed any more than conventional reefing?

right. where is that damn evidence?

[HR42]

Originally Posted by Medved

Hi all, I am a power boater who is converting to sailing. Passed ASA 101 few weeks ago and scheduled 103/104 for mid Sep. I am still in my research phase as to which boat to go after. I will be sailing single handed or short handed, and really liked in-mast furling on a Jeanneau 440 I got a chance to sail. That said, I am trying to understand pros and cons between in-mast and in-boom. I saw in and around Annapolis a number of ocean going sailboats with in-boom furling, but cannot find much info on those. Any insight from folks who have sailed with these are greatly appreciated.

I have just come across this thread and don’t want to read it all, but I will pass on my observations of the leisurefurl in boom. I fitted it to a 89 hallberg rassy 42. I hope I’m not repeating what many have already said. My opinions are thus,

To raise or reef you must turn the engine on and point it into the wind, ive tried pointing the boat into the wind under the power of the genoa whilst then hanging the boom right out and it will not consistently work. I found the need to do this encouraged me not to adjust the sail area as promptly as I should have. If you try to do it you will ruin the sail around the bolt rope area.

If you’re using one for the first time you really need someone experienced to fit the sail and show you the pitfalls. It took me along to time to realize a one stage that just a slight adjust of the clew tension was needed.

Plus I’m sure you’ve discussed boom to mast angle and the necessity for it to be spot on.

If you really want this set up though buy two mainsails. So as you can destroy one on your way to proficiency with this set up.

[Dockhead]

Originally Posted by Paul L

I was just wondering, as I only have one offshore passage experience with in-mast furling. While cruising I primarily use the back stay tension to tightened up the headsail when beating in higher winds. Vang is enough to control the main sail.

Yes, that's the way it's generally done. I don't have a backstay tensioner on my boat, so forestay tension is pretty much fixed (and in the next couple of days I'll be adjusting mine), but those with more flexible masts than the Selden one can use a backstay tensioner for that.


As someone else mentioned, the foil is loose in the mast and you don't get any mainsail adjustment from a backstay tensioner on an in-mast furling rig. If you did manage to bend the mast enough to affect the mainsail, you would interfere with the foil rotation.


Yes, we have very good control of mainsail shape with vang, mainsheet, and outhaul. Actually better than with a normal mainsail because the foot is always loose and free even when the sail is reefed. Except for draft location control using mast bending, also we lose draft location control when reefed (because halyard tension no longer has as much effect when there are rolls in the sail), but this is academic because in-mast furling mains are cut flatter, and get flatter as they are reefed, draft moves forward, which is just what you want. And the amount of draft is easily controlled with outhaul and vang (and/or mainsheet when close hauled).



We generally need draft location control less because of the flatter cut sail. What we lose is the ability to shape the sail very full for power in light wind, and combined with lack of roach, so we give up a lot of performance in light wind compared to a normal main. That's why you would never want in-mast for racing, and I wouldn't want it down South in the Med or someplace like that, either. But those of us who sail where the wind is 20+ most of the time don't really care about this much -- light wind is not a big part of our sailing. I do think, as I've said, that this is why in-mast is popular, further North.

[Dockhead]

Originally Posted by Kenomac

I’m surprised your mast doesn’t bend, our Hood masts both have a very pronounced bend which can be easily adjusted via the backstay tensioner. The bend doesn’t effect the electric furling in any way.

Have you tried tensioning your backstay? Can you have a rigger adjust everything to allow for bend?

I do my own rigging adjustment and do adjust the backstay tension for fine tuning of forestay tension.


But the mainsail is not affected by this.


I have no experience with the Hood system so don't know how that works; the Selden system uses a very rigid mast.


I am fine with the Selden system -- the rigidity of the mast simplifies standing rigging setup, which is very welcome with a complicated three spreader rig like mine. And I don't find that I miss this control with regard to the mainsail.


On my previous boat, with a bendy one-spreader rig (and straight spreaders, not swept ones like this boat), I used mast bend primarily to reduce draft of the mainsail, and move it forward, in order to depower the sail, or more accurately, reduce drag. This would simultaneously add tension to the forestay, so I would crank up the backstay tension when going upwind in stronger wind. But the in-mast furling main has such excellent control of the amount of draft and can be trimmed so flat with outhaul and vang, that I don't miss this at all.


Another thing is that you need less control range with laminate sails, which due to the apparently total lack of any stretch, can be trimmed through a wide range of shape with small control inputs. I can trim my carbon mainsail so flat with outhaul and vang, that I can just about feather it if I need to (and that is sometimes exactly what I do with big gusts or squalls, instead of taking it in, although that is also dead easy).



That makes mast bending even less relevant, in my case.






One last factor is whether you have aft-swept spreaders or not. A boat with straight spreaders gets all the aftward force vector on the top of the mast from the backstay. But aft-swept spreaders, which racers hate, also pull or hold the mast back via the cap shrouds. Someone who knows more about it than I do can probably explain it better, but I don’t think adjusting the backstay has nearly as much affect on a rig with aft-swept spreaders.

[Oceansailor]

Originally Posted by Dockhead

Selden system - very rigid mast and no bending. This is a disadvantage of this system. But you have really good control of foot and leech tension via vang and outhaul, and as a bonus, the outhaul control is not impeded when the sail is reefed.

Selden (system) mast will bend if you have a proper backstay tensioner. I do agree that with vang, outhaul and laminated sails there is little need for bending the mast from a sail trim point of view. But in most cases mast bend is positive as it stabilizes the mast. Personally I do not like to sail in rough seas with a straight mast.