In-Mast Furling on Cats - Pros & Cons . . .

[stacy]

Jennius, would you please describe your downhaul system, thanks

[Cotemar]

It’s only a matter of time as Cats become more popular, there will be some sort of Main Sail Furling System for cruisers. Most of these boats have a lot of conveniences and main sail furling will be one of them in the future.
Main Sail Furling systems used to be an expensive option on monohulls and now it's standard.

May end up being a boom furling system ? Who can tell at this point, but cat companys are feeling out the market by adding this furling option slowly and seeing how many takers go with it.

If Lagoon or Fountaine Pajot added this as an option I would have one right now and believe quit a few other would also.

As a side note: If you take two identical boats except one has in mast furling and try and sell these two boats. The in mast furling boat will sell first at a better price which kind of tells you what cruisers are looking for.

Mark

[colemj]

We see many cats with in-boom furlers, so they are somewhat common on catamarans. I don't recall seeing any in-mast furlers though. Again, most catamaran rigs are specifically designed for a very full roach using a small, fractional rigged headsail. A flat, hollow cut main, like that necessary for in-mast furling may leave the boat very unbalanced and underpowered - more so than doing the same on a monohull.

This is just my opinion - I have no experience with the systems or sails. Also, I agree that any system making the handling of the mainsail easier on the crew is an improvement.

We have an electric winch on our boat with all halyards and reefing lines led to the cockpit. Each reefing line is a single continuous one, and it is dead-simple to put in, or shake out, a reef without ever leaving the helm seat. When we release the main halyard to strike the sail, the sail instantly falls straight into the lazyjack/sailbag. I do have to eventually zip up the bag when we get to port, though.

A question for those with in-mast or in-boom furlers: can these sails be reefed or struck completely while sailing off the wind? Downwind? For a cruising boat, I believe the ability for this to be an important attribute.

Mark

[Cotemar]

Here’s a very nicely written article from Practical Sailor about In-Boom Furling: Five Systems

http://www.practical-sailor.com/marine/boom-furling-systems.html

Schaefer Marine’s boom furl is designed to work upwind or down wind, because they have the track articulates with the boom.

Mark

[mdsilvers]

I am with you colemj on the in-boom furling. For myself, that would be an option I would consider. In-mast as I stated above for me was just not the right choice, and we are happy with our decision. Clearly as stated before different people will have different needs and compromises that are unique to their situation. There is not a 'right' answer that will apply to everyone. Just pros and cons that must be evaluated.

A key factor on the Antares is all lines run to the cockpit, power winches, etc...so there isn't a 'significant' difference in ease of use over furling. If I had to run forward to reef, drop main, etc...I might have made a different decision.

[Jeannius]

Stacy... Our system sounds very similar to Colemj just with the addition of a 12mm line taken to the top car on the mainsail. If we are off the wind when we want to bring the main down we just put the line on the electric winch in the cockpit and pull it down. I've done it successfully with the sail full in 40 knots of wind and it comes down without a problem. A great security feature to have if you get caught out.

I do like the look of in-boom furling for cats. One of our fellow round the world boats is a Privilege 445 and they have one (can't remember the name of the system right now) They did have problems at first and had to have the main recut to get it to work properly but they love it.

[SailFastTri]

Whoever says they don't jam just hasn't had it happen YET!

Same with genoa furlers, which have proved reliable but they DO fail, however they're not enclosed so there is an option to wrap the sail manually.

[DotDun]

I agree with others - mast furled sails are not an option on most current production cat designs. Move the mast aft to the middle of the boat and you can have a rig that is suitable for mast furling.

A general design criteria for most production cats is to place the mast forward of the salon which provides a major convenience/selling point - a huge open living space. When this happens, rig designers normally use a fractional sloop with a large roached & horizontal battened main sail.

I was interested in boom furling and investigated such for my rig. I decided against it for multiple reasons (in addition to the $$$). First, the furling boom must to be within 3 degrees (+ or -) of 90 degrees off the mast. This would require me to raise the gooseneck ~5 feet, I didn't like the loss of (low) sail area doing such. Second, the mast is not only raked aft, it's curved. The bend would have to come out. My opinion is the designer raked and bent the mast for a reason (move the wind force aft), do I really want to change the design just for a little more convenient rig? I decided not.

I find it interesting that as I get more experience with 'things that can happen', I continually gravitate towards the simpler solutions. Mast and boom furling are more complex than slab reefing, lazy jacks, and a sail bag. I still go forward to manage the main sail, and I've done it in 50kts winds and 10-12 foot seas, but I won't say I liked it in those conditions.

[yeloya]

As someone who is mostly on catamaran but also sailing on various monohulls as well, to me furling main sail, wheather it is on boom or mast, wheather it's a mono or cat should be out of question..On mono, on some very specific cases you may prefer furling main but on a cat it's not even worth talking about. If you believe hoisting the mail is a pain (even with electrical winch) or reefing is a tough job, you should go for a mono or motoryacht.

For the cat, the main driver is the main sail. With a compromised main sail, the cat is heavily handicapped and become absolutely senseless.
Moreover, being in charter and service business, I can tell you that the furling sails loose their shapes already in a year on mono (cannot be trimmed anymore) and do last max 3 years max. I would have guessed this will be the case even earlier with a cat, given the forces they are exposed to. The classical main both on mono or cat lasts at least 4, sometimes 5 years. (average 20-25 weeks of charter per year)
If someone is saying that the furling sail do not jam, they do.. And most of the time in the worst times. And if the relatively small main of monos do jam, huge main of the cat would jam even more often. If that happens on a cat, you are at even higher risk, given the size of the main.

So "push the button" hoist yr classical main or "push the button" and start yr engine..

Cheers

Yeloya

[mdsilvers]

Here was a some good feedback I received on this topic when I was doing my evaluations...and I thought I would share.

"Aeronautical engineers have often referred to the Spitfire airplane's wings as being the most efficient shape with its elliptical plan form. Transferring this concept to a sailboat's sails means that we want to try and create as elliptical as possible a top to the sail plan. The bottom end of the sails are "capped off" by the endplate effect of the deck (and even more locally by the Maintamer) to keep the higher pressure air from bleeding off to the low pressure side of the sail just as the fuselage of an airplane would do, but the "wing tip" at the top of our mast is a different condition and we look to reduce drag by trying to achieve as best we can with cloth and sticks that elliptical shape. Picture in your mind the shape of sailboard sails with their bendy masts, square tops and rounded leaches... or modern racing keelboats with their fractionally rigged foresails blending into a tapered and flexible topmast that supports a "fat headed" main sail: both close the door at the bottom in different ways by either leaning the whole rig back until the foot of the of the sail approaches the board or by keeping the boom low to the deck and using deck sweeping head sails respectively, and they both use combinations of flexible masts and stiff battens to optimize the profile. Obviously, we aren't going to go to such extremes on our cruising cat, but the theories still hold true and deliberately contradicting them just doesn't seem wise to me. It is a game of balancing compromises.

So, why don't we go with a sexy square-top main and a deck-sweeping genoa? The highly peaked battens needed in a square top make the sail virtually impossible to stow on the boom because the batten keeps the top portion of the sail from being completely lowered without removing and replacing the batten every time, and our wide (spacious!) cabin interferes with the sheeting angle of any attempt at a deck-sweeper. The sales pitch, of course, is that it would interfere with your visibility from the helm...

Other issues? The mast itself is a larger extrusion (more turbulence at the leading edge of the main) and heavier (more pitching motion in a seaway).

Is it safer to reef? I don't think so, as either version can be reefed from the protection of the cockpit; one by easing a halyard and taking-up on reefing line, and the other by easing the outhaul and pushing a button.

Is it easier to reef? In either case you are easing a line with one hand and pushing a button with the other. What it does make easier is the fact that it eliminates the need for you to monkey around to cover the sail at the end of the trip.

What happens when things go wrong? The in-mast version gains a safety advantage here because it can be furled manually while standing at the base of the mast (the outhaul is accessible and controllable from that position as well) if there is an electrical problem. The conventional set-up would likely require you to climb up on top of the bimini to sort out any problems which may not be a very nice place to be in conditions that are requiring you to reef in the first place.

How well does it sail whilst reefed? The conventional sail removes sail area from the bottom when reefed, maintaining its roachy (efficient) top profile. The furling version becomes even more triangular as it disappears into the mast becoming less efficient and because of the amount of rake in the mast and upward pitch of the boom, the clew wants to lift away from the boom as it is furled making it less controllable and the sail will tend to become more full in shape which creates more heeling force and less forward drive. Just because we need to reef is no reason to give up efficiencies in performance; we want to increase our safety, not reduce our speed because being able to cover ground relatively quickly is a cat's greatest inherent safety feature.

How much more does it cost? I won't step on the salesman's toes, but I think the two options are quite comparable in price considering that the Maintamer can be eliminated to help offset the added cost of the rig and electrical equipment. The main sail as well would likely be slightly less expensive than a conventional main simply because of the reduced sail area.

I'm trying hard to not sound biased and just let the comparisons make their own arguments. There are definitely merits to the in-mast furling feature, primarily the ease of stowage, so it is just a matter of deciding which suits the manner of sailing that you intend to do. Regardless, the rest of the boat beneath it is the same...."

[caribcat]

I had an in-mast furler that was custom built by Doyle on an 80 foot cat I was running some years ago. Fuel consumption went right up after as we motored more once it had been fitted because it was so gutless!

It was supremely easy to use when head to wind in light weather, but chose to go wrong when we really needed it. We used it 2-3 times a day 300+ days a year. It the sail wasn't perfectly set it would jam, though mostly this required us to back it off and try again and the more this happened the more the leach became chewed up and therefore liable to jamming! It also required 2 people to put is away -one to stand directly below the mast monitoring the sail pressing the button, the other to keep the clew tensioned. The beautiful North main on thoroughly tune-able mast it replaced could be dropped by one crew, shame the previous Captain chose to blow that mast off the deck in a confused sea over Saba Bank!

The sail materials are thinner and lighter to keep the roll small. These means the sail stretches easily and the centre of effort is all over the place. I found that this eventually put loads more pressure on the rig with the energy not 100% being used to push the boat forwards but a fair amount of it just ending up just making the rig bend. The rig could not handle squalls that we would have previously just 'travelled-down' for. Yet again, we used more fuel as we now didn't always want to get it out in strong winds!

The mast had the rigidity of a fly-rod. It had to stay perfectly in column to work so we had a hard time putting any tension on it. The meant the balance of the boat was out and any time the boat slammed a shock wave went up the flaccid mast, shaking the already frail furling kit.

Once people begin cruising they realise that they put the sails up for days/weeks on end. Reefing occurs more as a nightly occurrence as opposed to a weather reaction so you get practised.

In boom is better but has so many restrictions and issues I wouldn't choose it. Either have a good coach roof to walk on and a decent stack pack (as opposed to usually ***** factory offered lazy bags) or a Park Avenue boom if you boat is larger.

Tom

[muskoka]

I've sailed an in-mast furling mono and would never recommend that set-up for any boat as it really strips the performance (and consequently the fun) out of sailing. You can't cut an in-mast furling sail nicely, nor can you properly batten it, so you're stuck with something that you can't trim and looks plain awful. There are better solutions: lazy jacks, power winches or in-boom furling.

I'm perplexed as to why anyone would buy a sailboat and select a system which gives you such a crappy mainsail. It's just plain wrong.

[tsmwebb]

Originally Posted by simonmd

I think this is becomming an old wives tale. The's been much discussion in the monohulls section and while it's accepted it is possible, it very rarely happens and when it does, is usualy easy to sort out. It always seems that the pros outweigh the cons, from what i've read on here anyway.

FWIW, I've seen them jam. The fix can require going up the mast at sea... For instance, I know an elderly couple who managed to pull the top shackle into the mast groove of their Seldon in mast system while offshore. They couldn't reef and were not strong enough to pull the sail down the mast. Not good. Also, furling masts make horrible neighbors when the wind blows across their big slots and howls the night away. My feeling is that if one wants to go that route a better solution is behind the mast furling. It looks kind of agricultural but otherwise is simpler, easier to maintain (and therefore more likely to get maintained) and less likely to foul. I like the in boom furlers in theory but I think it is critical for an offshore cat to be reefable while running and the systems I've seen don't look capable of that.

Tom.

[tsmwebb]

Originally Posted by mdsilvers

...

"Aeronautical engineers have often referred to the Spitfire airplane's wings as being the most efficient shape with its elliptical plan form. ..."

Maybe too wonkish but elliptical span loading is probably not most efficient (for any given definition of efficiency) on either airplanes or sailboat rigs and hydrofoils. Tom Speer has a nice paper on the subject here: Minimum Induced Drag of Sail Rigs and Hydrofoils.

An idea that occurs to me as I type this is that a carefully designed roller furling system might work well behind a wing mast. Ideally the mast would rotate slightly more than the roller furler so that there would be a slot between them with the leading edge of the sail to weather of the aft edge of the mast. Of course, a slightly taller rig, a bit of weight reduction or a touch more sail area can probable produce as much performance gain at a much smaller cost. But the truly dedicated tinkerer might be rewarded by the challenge of the thing. (The virtual tinkerer on a budget might start here: JavaFoil).

Tom.

[simonmd]

Stumbled accross this interesting site whilst doing my own research on cats. Choosing the right offshore, live-aboard catamaran.

Intersting section on common questions, here's their number 4,

Why won’t anyone recommend a furling mainsail?
A cat is very dependent on a large roach. A fully battened, full-shaped mainsail works best. The jib serves more as a foil to direct the air flow ( consequently you don’t need a large jib.) This makes the boat easy to sail and tack, and very powerful. This type of sail would need to be excessively flattened and compromised to make it possible to furl it in the mast boom.