Jon:
Yep I’m sure it would open up a can of worms among the racers. But, only if a boat with such a mast past any other Nonsuch. I was thinking more from a cruisers perspective. Your comment about the truss tower being stiffer is interesting. I wonder is the carbon fiber Nonsuch mast stiffer than an aluminum one and how does that affect it under sail if anybody has any experience with the two?
Mike Girardo
BIANKA
1986 30U
http://biankablog.blogspot.com
— On Thu, 6/18/09, Jon Fitch jfitch@FLASH.NET wrote:
> From: Jon Fitch jfitch@FLASH.NET
> Subject: Re: KLACKO & finite mast life and thinking outside the mast
> To: NONSUCH-L@LISTSERV.AOL.COM
> Date: Thursday, June 18, 2009, 4:06 PM
>
> On Jun 18, 2009, at 7:17 AM, Mike wrote:
> > Just because trees were round the orignal masts were round but, does that mean they always need to stay round? I’m just asking? Anyone more familiar with structural engineering and metalurgy care to chime in?
>
> Mike,
>
> Round isn’t such a bad shape. On a Nonsuch mast, the stresses can come from any direction, so equal strength in all directions is desirable. And for minimum windage, you would like the smallest possible section. These two constraints dictate a round tapered tube, just as a Nonsuch has. If it could rotate, a “D” section, or perhaps a thick airfoil section might be better, but a rotating mast has it’s own set of challenges (ask me how I know…). Also, the flexibility of the tube has many advantages for sail shape that would be lacking in the truss tower, which is nearly perfectly rigid.
>
> I don’t think your truss-type tower would be class legal, but I don’t think you would get many protests either - you would be the back marker as the windward mark every time!
>
> Jon Fitch
> ‘Anomaly’
|
Mike,
My understanding is that the carbon masts were designed to mimic the stiffness of the aluminum one to make the class competitive, make sails interchangeable, etc. The main difference I notice in the carbon ones is that since the material is lighter, it does not whip nearly as much with the sail furled when crossing wakes and such. The lighter tip stores less energy when it gets moving, and settles down much quicker. That might be partly due to the carbon laminate having better dampening characteristics.
Jon
I own a 26 with aluminum mast and sailed the CF masted 260, 324, and 354 quite a bit as Chesapeake dealer for the last incarnation of Hinterhoeller. I have sailed alum masted 30s but not much on 33 or 36 just a time or two on each.
The CF masts are a little stiffer but much lighter so the heeling and pitching is significantly less on a CF mast. Of course sailing performance depends on the mast/sail combination and with the 260/324/354 North Fogh made us nice big-roached sails to take advantage of the better mast ond lower CG. There were also carbon wishbones.
Very subjectively there was a noticeable increase in performance on all points of sail with the new rig. We have chop on the Chesapeake and I remember thinking that it was much nicer in light air and chop with the CF rig and big roach sail. “damp” is the word I am looking for, nothing to do with spray. She hits the wave, pitches once, settles, goes. I believe the sails for the CF masts were a bit flatter than what we see on alum masted boats…the CF mast sails also had full battens. Pretty sure they were strong track. The boats with CF masts now that I think of it had some complex matching sail design software which took the bend characteristics of the mast into account.
At the time that we were pushing 260 324 and 354 the Melges 24 was a big sensation with its carbon stick keel, rudder and pole. I remember thinking then then if there were any boat that was a perfect candidate for a carbon stick it was the Nonsuch.
You sail them (26 and 260) the same way, the CF stick boats just go faster.. more comfortably…in all conditions.