In Mast Furling Retrofit ??

[redsky49]

My current boat, purchased used, had a behind-the-mast furler that was very disappointing, to the point I ripped it all out and started over.

As I get older, I have considered in-boom furling, a more conservative approach, especially if going off shore.

In the meantime, lazy jacks are very helpful.

[boatsail]

I am very interested to hear the first hand accounts involving the behind the mast furling. What makes it so bad. I hear about "ripping it out", "kill performance". It seems like the most economical means of putting up and taking down the main.

How much does it change pointing ability?

How much does it change speed?

[redsky49]

It was extremely difficult, and quite frustrating, trying to achieve a good sail shape when fully unfurled. The draft was difficult to control. When partially furled (reefed), wrinkles would appear. Smoothly furling the sail completely was a challenge, and usually had to be (at least partially) refurled every time.

It could be that this particular sail was blown out, or was poorly cut, or simply the wrong design. I just don't know.

The gooseneck fitting seemed to be a weak point, as was the entire foil that was supported only at the top and bottom. I worried if the rig could take heavy stress.

Finally, the manufacturer was out of business and there was no support.

In my case, it was like a breath of fresh air to pitch the entire mess and go with a slab reefing, loose footed full batten main. Pointed several degrees higher after the change, lost all that weight up high, and finally achieved the sail shape, over several wind speeds, that I had sought.

[Stumble]

Boat,

The problems I have experienced can be summed up as....

1) the furler just doesn't work, because it is hard to get enough tension on the system to get a clean roll. This leads to a lot of jamming, and cussing to get them to work.

2) the separation from the mast to the luff of the sail allows air to slide by, and creates more turbulence. So just where on a normal main the air starts to reattach after getting knocked around from the mast, it hits another protrusion that stirs it up again. It also acts to allow wind to spill to the back side of the main since you don't get a boundary effect from the mast.

3) no battens

4) no leech

5) lost sail area

6) the luff can't be kept on centerline, so it is always spilling off to leeward. This costs you point.

I have never seen any numbers on them, but given that a typical in mast furler costs you about 20-25% of sail drive, then I would assume that these are more in the 25-30% of power range. I would also guess another 3 degrees in lost pointing.

It could be worse, I would doubt it would be much better. And they are expensive...

Personally I like lazy jacks, I would consider a stack pack or A Dutchman system comparable. The in boom is nice but very expensive by comparison. Reefing on the mast to me just has too many draw backs to justify it.

[redsky49]

"2) the separation from the mast to the luff of the sail allows air to slide by, and creates more turbulence. So just where on a normal main the air starts to reattach after getting knocked around from the mast, it hits another protrusion that stirs it up again. It also acts to allow wind to spill to the back side of the main since you don't get a boundary effect from the mast."

I had forgotten about this, and it was a real drawback. You would often get a funny shape or ripple at the leading edge of the sail.

[Rakuflames]

Originally Posted by SVAquilon

I plan to purchase a larger boat for cruising the near future and would like to be able to perform all functions from the cockpit. Trying to get a feel for the cost of a newer boat with upgrades vs. a older (cheaper) boat and adding what I want. Thanks

You can perform all functions from the cockpit without a furling main. Just for example, you can have a push-button system that raises the main if you want to lessen the physical exertion you have to exert to sail a bigger boat. Then you'll still have full control over sail shape, etc.

[vtcapo]

I have a behind the mast extention by Selden that houses a Furlex roller furling main on my cutter rigged Slocum 37. The extention makes it more aerodynamic. On our test sail even though she was not rigged perfectly we got good sail shape and none of the wrinkles or luffing discribed. When she did luff which was minor we just pulled down on the luff cord and the main stopped flapping. As far as performance, it was blowing 8-13 knots and I got her up to 7 knots using full main and a 150. Not bad for a 14 ton double ender.

However, I only sailed her once so I cannot say for sure if I will run into any of the problems mentioned above. Besides that's how she came and I will live with it.

It sure is nice to control reefing from the cockpit.

RT

[SVAquilon]

I'm with you vtcapo, reefing from the cockpit is nice and where I want to be in my next boat. Thanks

[boatsail]

I did not start this thread, but thanks so much guys for the great information. I'm looking at new sails in a couple of months and wanted to look at all of my options.

[Dockhead]

If you want a furling main, you will get much better results if you buy a boat with the whole rig designed for it. You have less sail area for a given luff length with a furling main, so the rig should be taller, and ideally, the keel should be deeper. The furling mechanism should be inside the mast. The rig should be designed to limit mast bend, as in-mast furlers don't tolerate that.

I have this system and it doesn't suck. I am not sure that it is a lot less work than a regular main with lazy jacks. Reefing from the cockpit in infinite steps and without luffing up is the one big advantage. That, and excellent storage of the main protected inside the mast with no need to flake or cover.

If I had a regular battened main I would never dream for a second about trying to convert it, an expensive enterprise with little prospect for a good result.