Freitag, Januar 05, 2007

New Sails

In my August theme "Where do you sail" I had mentioned that I need fuller sails for my Bull 7000 due to a lack of power in light air and choppy sea. I am working on this issue now and as always the big question to me is about: "who shall make these sails...". I have many friends in the sailmaking business, some had been fine competitors, some I had sailed together with, which makes the decision rather difficult. Some I had distributed myself but at the end of the day it comes down to: "who can provide the best service and who has a knowledge in the class".

For my Bull 7000, I have always trusted my English friends at Sobstad as they have sailed the Bull very successfully themselves. That has been the reason why I have ordered the headsails always from them. You can see from some nice features that they really have a knowledge about, how the boat is best being rigged. Subtle detailing. The mainsail on this boat is another story, as I have a carbon mast in the boat after the aluminium mast broke some years ago. We burried the bow into a steep wave trying to pass a 44ft X-Yacht in strong wind. We did not release the Top Gennaker immediately as we should have, and so the disaster started. The top of the mast kept on sailing, the boat, deep into the stern wave of the boat which we chased, stopped.

The new "kind of DIY" carbon mast is very stiff, maybe we used a little bit too much carbon as a safety factor and the stiffness gave us some problems with the first new mainsail. This one for obvious reasons, had been ordered locally. Our friends at HOLM Segel, just around the corner, had to re-measure and to re-cut the luff twice as I had always seen the sail as a test sail for the new rig configuration: Taller mast and shorter boom was my aim. Now it is time to do something better. Of course a lighter mainsail made of kevlar and maybe some carbonfibre to follow the loadpaths. This normally is difficult or better impossible to get from your sailmaker around the corner. But there is development happening in the market and this year the Dimension-Polyant brand offered the 4th Dimension pre-fabricated highTech sails to smaller sailmakers to service their customers. This is the way to go. The "local sailmakers" can purchase loadpath optimized sails in one piece but without all the necessary clews, rings, reefs and such. They put on the luff and the leechcord and will fit the sail to their customers special requirements. In my case, a square head, loose foot and high tension cunningham which shall open the top when pulled.

There is lot´s more about sails and adjustments which I have learned during my sailing experiences. One thing for sure which amazed me lately had been the new and very strong boom vang which I saw on an exhibition Laser. This nice piece of equipment allowed me to pull until the boom hit the afterdeck of the boat. Without much muscles. Compared to the new Laser, which K. could have used during the Christmas break in the Med (no wind at all, story following later), that fitting on the exhibition boat was so much better that I will try to get it for my own downhaul. Not only an eye-opener but also a leech-opener. American made.

Kommentare:

Eliboat hat gesagt…

How did you build the mast? DId you use prepreg, wet preg...vacuum bagged? I'm quite interested to know. Happy new year!

-Eli

Fred hat gesagt…

Eli, thanks for your comments and happy New Year for you to. Appreciate very much your blog and boatbuilding section.
Mmh, the mast: hand laminated, vacuum bagged in two halfs with spline on the sides. We started with a 45/45° layer, than 2 x 300g/qm UD´s and 45/45° always after 2 UD layers. Finished with 45/45 and maybe, if "black carbon" outside important, have a carbon twill fabric on top in 0/90°. On my companys homepage. www.ctmat.de you can find under: "download", the CTM magazine nr. 22 which has an article about masts in composites. Of course in German but you find thicknesses of fabrics in a table. For a first timer we did built up thickness to an equivalant aluminum tube. But maybe.... you know these rules of thumb. But than, it might be interesting for other readers.
smooth sailing-Manfred

Eliboat hat gesagt…

Very interesting Manfred. What kind of Epoxy were you using? You might want to take a look at Vectorlam software from the Vectorply corporation so that you can analyze laminates. It is free to download at www.vectorply.com. While it is not really suited for mast design, you can easily evaluate laminate thickness and other critical properties. I will check out the Magazine link and pass it off to one of my German speaking friends for translation

Fred hat gesagt…

Thanks for the Link. Being the distributor, we are using SP epoxy, in this case Ampreg26, cause it has the best mechanical properties.