Hi Eric. I own SM 299. I have never had a jam on the main. I dont have battens. I find the system very forgiving. I just work the two switches to keep the sail off tight as it rolls

 I have never done it but I suspect the biggest cause of jamming would be rolling very loose causing bunching. I find if I overload the motors the breakers pop long before any damage. This is my first in.mast furling. I was a lifetime racer so had a strong predudice against in mast sustems. Now as a cruiser (performance orientated) I would have nothing else. I would never add battens.

Regards

Danny

SM 299 Ocean Pearl

Hi All,

we follow the discussion with great interest. But up to now we did not see any comment of an experienced sailmaker. So we decided to ask Jens Nickel and his oppinion. Jens is a well known German sailmaker (Segelwerkstatt Stade) with excellent reputation. We think his answer of interest to all of you. Here my “free” translation:

“A furling mainsail without battens (excuse the expression) is simply crap. The top 18 to 20% of the sail only create drag (resistance) and no lift/buoyancy (more heeling, more rudder pressure, less speed).

- A mainsail with short vertical battens is already better, but the leech rounding is still limited, which mitigates the points described above but does not really cancel them out. Furthermore the short battens have no reefing function (see below). The main reason against short battens, however, is that they can get jammed in the mast on the starboard inner mast edge (when, as usual, furled anti-clockwise). This does not happen often, but when it does you have a real problem.

- The only argument against full battening is the higher price. These sails produce more propulsion, less heeling, less rudder pressure. Furthermore, the battens are perfect reefing steps. The battens are not parallel to the luff, but slightly slanted. Reefing should now always be done in such a way that the batten is always completely furled into the mast. It then winds itself slightly around the pole in the mast as a spiral and thus stretches the "new luff" a little.

After more than 25 years of producing fully battened furling mainsails we have never had one owner who was not satisfied with the conversion.”

I have to add: The battens are round (diameter some 8 to 10 mm) and made of two different materials: glass fibre and carbon, the latter used in the upper part of the sail to keep the aft part stiff.

Further I have to add this: When we got our Mago del Sur in March 2016 she was fitted with original genoa, main and mizzen. (The jib had disappeared.) Main and mizzen were bare of the vertical battens. The leeches of all three sails were worn out and causing enormous flapping and vibrations. In spite of that the performance of these sails was surprisingly good. When we had to furl in the main the first time during our delivery trip (with winds of some 7 Beaufort) the furling system blocked because of overload. Thus giving us the chance to furl in the main by hand. Which worked very well.

In July 2016 we ordered new genoa, jib, full battened main and full battened mizzen from Jens Nickel. Since then we never had any problem to furl in or out main and mizzen. We can do it on all angles to the apparent wind and in all wind speeds we have met until now. The furling systems never blocked. Meanwhile we sail the full batten sails some six years without any problems.

But there is one aspect you have to know if you think about a full batten sail. The connection between halyard and sail has to be reliable. Once it happened that a boatyard fitted our main to the mast with an unreliable connection. I insisted to change it but I forget to proof the connection after the main mast was fitted on the boat. After 3 hours of sailing the main came down -  more or less half way and creating an interesting S-shaped new sail design because the battens blocked the rest of its way down. It was quite a nice job to get the battens out of their pockets piece by piece …
But finally we managed it to get the sail down.

Martin Birkhoff
Mago del Sur 54#40
sailing near Cap Trafalgar heading east

Hi Randall,
here some pics.
The mizzen (2 pics) is unfurled completely. You can see the first batten is in a closer distance to the mast, the space between the next battens is larger. Its not to see that the battens are slightly slanted, but they are. The mizzen is trimmed to go as close to the wind as possible with quite some knots of wind. Otherwise we would release the outhawl of course. 
The main is in its "first" reef meaning the first batten is furled in.  

Regards

Martin
Mago del Sur - 54#40
La Linea, Spain

Hi,
here a pic I made today. It shows the fourth of five battens of the main. I furled it to a position to demonstrate the slant of the batten. The top of the batten pocket has disapeared in the mast, only the last stitching is visible. At the lower end the batten pocket is 2 cm out of the mast. The longer the batten (first, second and third batten) the bigger this effect.
Hope this pic is helpful.

Regards

Martin

Mago del Sur - 54#40
La Línea, Spain

Hi Martin,

Very interesting and many thanks that you made us aware of the way a sail can be build.
I checked the website of Stade and almost sure I’m going to visit them soon to discuss the possibilities for our 54.
Regarding the furling, you wrote that you never had problems with furling in any wind and any direction you furled the sail. Is that correct ? 
But with the battens all the way down doesn’t get the rolled sail too big for the space inside the mast ? 
Did you experienced a difference in power of the sail or less or helm compared to the sail with the short battens ? 
Do you still need a leech line to prevent slapping ? 
Are there any negative effects to this way of battens in a sail ? 

Best regards 

Laurens Vos 
Fun@Sea - 54#92
La Rochelle 

1. Until today, we had no problems furling and unfurling the main and mizzen, no matter which angle to the wind the boat was facing and how strong the wind was.

2. We had these concerns too. However, there is enough room in the mast. When fully furled, the mainsail leaves about 1.75 to 2 cm of space between the sail and the mast chamber measured at the bottom of the mast chamber. It should be noted that on Mago del Sur both the main foil and the mizzen foil have a diameter of 35 mm. You should explicitly point this out to Stade if you have a 40 mm profile for the main. In all cases it is an advantage if the foils are reinforced by an additional aluminum element which is inserted in the foil (available by Amel).

3. We cannot answer the question about differences. The old sails had lost their battens and their leeches and aft parts including the leech genoa were no longer standing. We changed all sails at the same time so we could not recognize which effects were caused by the genoa and which by main and mizzen. I beg your pardon, we cannot make a reliable comparison.

4. Both the main and the mizzen are equipped with a leech line, which is usually not necessary. (This is different with the gennua, where we have to use it regularly).

5. The negative effects are

•         The sails are more expensive.
•         It takes a lot more work to take down the sails, as it is not easy to get the long battens out. At the jetty, we always take the battens out completely and disassemble them into their parts when they are lying on the jetty.
• If the halyard comes off the sail, you have a problem because the long battens prevent the sail from sinking down completely or from being pulled down. You then have to pull the battens out part by part, which requires a lot of work with the sagged sail. It is therefore important that the halyard and the knot at the head of the sail are in perfect condition and reliable.

Regards

Martin
Mago del Sur - 54#40
La Línea, Spain