to furl in mast, or not?

[Scott T-Bird]

I'm interested in this question, too. But I'm far more interested in a discussion about the performance of an in-mast main on a masthead rig. The engine of the masthead rig is the genoa. Does a furling main even have a performance disadvantage?

I'm pretty well convinced that the issue of jamming the sail is a non-issue when you take the necessary care (please stop arguing). I'm also interested in the size of boat where in-mast furling is a complete no-brainer. I'm hearing from the owners of boats greater than 35' that in-mast is best - by far. Perhaps for a 30' to 34' boat is flaking really that much of a bother? Flaking the sail on my boat is not a bother, but the broken sail slugs that I have been replacing lately certainly is!

 

[Dr. D]

I am pleased with the in-mast furling on our 34' boat. As I am often sailing by myself, not having to go forward to the mast is a big safety factor. It take some time to get all the parts set up correctly; raising the boom by about 7 degrees helped a lot. No jams (so far).

As far as the genoa and main interaction on the boat, it is no different from standard sail configurations. The genoa powers up the boat greatly, even when higher winds means both are reefed. About reefing: Since I can reef easily from the cockpit I find I will do so more often.

 

[Cat 310 #1 in GA]

In mast furlers jamb. They do. Often when it’s good and windy just when you need them to work. Also, you don’t get good sail shape and no battens.

Have had in-mast furling on two boats since 2001 (Rhodes 22 & Catalina 310) and both mainsails had/have vertical battens which really help sail shape. Neither has ever "jammed" for me but both have gotten hung up while trying to unfurl the sail. My mainsail has never gotten jammed or even hung up while furling it in but it has gotten hung up on the way out because it was not furled up correctly. When hung up it is easily freed by pulling inhaul/outhaul/inhaul etc as needed. It is all about having the right system, a decent mainsail and the proper technique with technique being very important. Every issue I have ever had is because of poor technique. I would never own a sailboat without IMF.
bob

 

[tfox2069]

Have owned my first in-mast furling boat for a year now. Previous boats were all traditional mains with slugs, some loose footed, some not. This is the first boat over 27' I've owned (H36), and I have to say I am very happy with the in-mast furling on a boat this size. Hauling the main up and flaking it on the way down on my Catalina 27 wasn't too bad, but I had to go forward to the mast on all boats previous to this H36 to douse the main (and some the jib - gasp).

I'll be the first to say you have some things to learn about in-mast furling to make it work well - but the same goes for a boat's engine, its electronics, and every other system on a boat. A traditional main would almost never be a worry since you can easily drop it to the deck. But reefing late, going forward in heavy chop - either of those two tasks carries risk with them in managing a traditional main. Its all about the risk/reward you're willing to accept as captain. I singlehand most of the time, and being able to handle everything with the main (and genoa) from the cockpit is a huge deal. Yeah, I've failed to get the boom at the right angle when trying to furl and wondered why it wouldn't work. Frustrating, but very definitely my fault - I knew better but forgot. My diesel wouldn't be forgiving for long if I failed to open the seacock for cooling water. That's not a "bad" feature of the diesel compared to an outboard, its just a feature of the system I needed to learn and - without fail - make sure I take that action before using the inboard! I believe the same about in-mast furling.

And sure, I do wonder what I might have to do if the furler had an issue which prevented me from furling a sail completely, but as others have said, I have always been able to head downwind, unfurl, think, adjust, and then refurl. As long as I can unfurl, I can drop the sail to the deck if needed. If it got caught partially furled - an admitted nightmare - wrap up what you can around the mast with line, and motor to a rigger. In my (admittedly) limited experience I haven't seen that happen.

I would be interested in someone's opinion who has managed a charter fleet with in-mast furling to see what their experience has been.

Oh, and someone said you can't have battens with in-mast furling - that's absolutely wrong. They're vertical battens, but they definitely help with sail shape. My slip neighbor has a Hunter 41DS with in-mast furling and vertical battens (my H36 does not). I know, as I've helped him pull them out.

 

[JamesG161]

Does a furling main even have a performance disadvantage?

Well maybe... LOL

Your main sail has to be cut at a specified angle. My main gives ≈45% of my wind power.
I must set my boom angle up a bit or 7° off horizontal for correct in-mast furling. Like @Dr. D post above.

One might argue, more main sail would improve performance.
Jim...

 

[Jerry Clark H356 SV Persi]

I’ve just thoroughly researched the batten issue and agree that it is the sail shape that is important and I considered a laminated tri-radial cut sail with Vertical battens for my new replacement just for that reason, but was worried about the extra volume inside the mast. Any future stretch - inevitable even with milar triradial cut - makes the internal furling more problematic over time. Then you have the batten and the pocket added to the diameter of the furled sail inside the mast. I solved this by buying North CDI cruising sails that are made and premoulded to the aerodynamic foil shape - with no battens- and have very very low stretch over their life due to the low stretch, high tech fibers in the sail itself and where the threads are laid in the direction of load. I’ll get them in about a week, so, have no actual experience yet, but this along with the proper halyard tension and boom angle should be the long term answer I was looking for. Time will tell.

 

[shemandr]

Regarding Scott's question about performance with IMF, I would say yes the IMF will not perform as well. But I'll qualify that to the Selden system on Hunters. The reason is that you can have a big roach on a standard main with the B&R rig because there is no backstay. I've never seen a roachy main on a IMF system. Also, Scott brings up the masthead rig question asking how much the main actually does. And I agree for masthead boats, on which the main is not the larger driving force, the loss of performance with the IMF is probably small or non-existent. I also agree that IMF is better on larger boats on which raising a main could be an arduous task. But I'll re-state my experience that furling the main on my H356 was WAY more work that running the main up on my friends J32C, which I could do by myself in less than 10 seconds.

 

[arf145]

Late to this discussion, but I have to say I love having in mast furling on our Bene 331. With it, I'm much more likely to raise the sails on an iffy wind day, because it is so easy. And it's easy to go out reefed and let out more as needed. The drama level when furling vs. the old days (for us) of dropping the main and standing on the cabin top while wrestling the sail and sail ties is near zero. Ours does require that you only furl with the boat into the wind and with the mainsheet and vang slack. Do that and it's always well behaved.

The funny thing is, when we bought the boat used I was a little disappointed that it had a furling main--was worried about performance. But that's not an issue for me--we don't race--and it sails fine anyway!

 

[Davidasailor26]

The reason is that you can have a big roach on a standard main with the B&R rig because there is no backstay. I've never seen a roachy main on a IMF system.

Agreed - there will always be some power loss with IMF. Neil Pryde claims the following, at least for conventional non-B&R rigs - “In-mast furling mains are generally about 18-20% smaller than the classic mainsails and the [vertical batten] mainsails gain back 50% of this lost area.” On a masthead rig that 10-20% loss in mainsail power might not be as hard felt as on a fractional, since the main itself is a lower percentage of overall power. On a B&R rig it does seem like the loss might be more since you could have such a larger roach.

 

[jeff356]

All systems have issues, once you understand the in-mast system it's generally reliable; we've had no major issues in 19 years. We have (now) a cruising laminate main, which, while somewhat more expensive than a regular dacron sail, got back some of our roach and has perfect shape even though battenless. It's great to be able to dial in exactly the amount of main you want, all from the cockpit in an instant. we've reefed in a sudden 30kt squall with no issues.

When you furl in what point of sail are you on? Do you care?

Jeff

 

[Cat 310 #1 in GA]

Head up just like standard main. Mine furls better with boom slightly to port.

 

[chuckwayne]

When you furl in what point of sail are you on? Do you care?

Jeff

usually head to wind, works best with the sail slightly to port. If the wind is light, we also furl heading downwind

 

[Captain Larry-DH]

wrap up what you can around the mast with line,

How does one accomplish that with a fractional rig and spreaders in the way?

 

[Captain Larry-DH]

it requires someone at the gooseneck to feed the sail i

I sailed as a guest on a boat with the Leasurefurl boom furler, and it did need someone on the track, who was constantly shouting "up/down" and "starboard/port" because it also needed to be just slightly off centerline to fee properly. It was a nightmare that took 10-15 minutes of fiddling every time we furled, unfurled or reefed. I would never want that on my boat.

 

[tfox2069]

How does one accomplish that with a fractional rig and spreaders in the way?

Fair question. Agree it would be very minimal - you wouldn't be able to wrap any higher than you could reach, but you could get some windage under control. The rest of the main would just have to flap until you could get things sorted.

 

[leo310]

On our C310 we have IMF as we are cruisers and not racers loss of performace is a none issues. The safety factor that is we don't have to leave the cockpit to reef the sail is a bonus. Also reefing has many points not the normal 2 or 3 and heeling is more in control.

 

[Barnacle Bill]

I have had a lot of experience with the Selden in mast furling mainsail systems on many different boats of various sizes through the years and I think it is a wonderful product that works very well. I have had experience with other brands and was not happy with the performance. You just have to use common sense using the apparatus. I also think Selden's Furlex roller furling units are the best engineered jib furlers out there.