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Cam Vs. No-Cam (Again)
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PeconicPuffin



Joined: 07 Jun 2004
Posts: 1220

PostPosted: Tue Oct 23, 2012 2:26 pm    Post subject: Reply with quote

konajoe wrote:
The reason other factors aren't discussed is because this thread was supposed to be about which type of sail is better at planing through lulls and which is better for pumping on to a plane.


Cams make planing through lulls easier. Camless sails are easier to pump (and jibe and tack and waterstart and ride waves and do tricks etc.)

konajoe wrote:
Did anyone try testing the effect outhaul on pumping, as I suggested?


People are going to tune their outhauls for best planing performance.

Pumping is primarily skill-dependent, not equipment dependent. A better sailor can pump onto a plane with a sail 1 meter smaller than a lesser sailor.
If your biggest priorities are getting planing in the first place, and then not falling off of the plane in a lull, rig a big cammed sail and enjoy. But understand that except for serious racing (when racers are out on 8.0s while the nonracers are tearing it up on 5.5's) there's no aspect of sail control that doesn't work better without cams.

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Michael
http://www.peconicpuffin.com
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speedysailor



Joined: 11 Sep 2007
Posts: 841

PostPosted: Thu Oct 25, 2012 5:55 am    Post subject: Reply with quote

konajoe wrote:
The reason other factors aren't discussed is because this thread was supposed to be about which type of sail is better at planing through lulls and which is better for pumping on to a plane.




There's nothing in the title of this thread that makes one think that pumping would be the subject of the thread. Most sailors don't pump to a plane so an "active" thread would certainly not concentrate on that hackneyed topic.
konajoe wrote:

There was a recent reference to 'active' sails. Both cam and camless sails have active leaches. The camless sails are the only ones active in the luff. Fuller in gusts, and flatter in lulls. Exactly the opposite of what you want.

I'm still working on the translation of that Italian article, but they address "tension" in a sail's leach and a sailor's attempt to reduce "stress" in the use of a sail. Futhermore, let me add that most of the internet posting uses a rather liberal definition of leach. In fact many should be using roach when they use leach. The leach is just the edge of the sail while the roach is a part of the sail. The upper leach should be floppy when a modern sail is rigged. It certainly would be a stretch in the imagination to think that this is "active" or has a life of it's own in spite of the wind. However, that would be what I would expect from a bull slinging salesman. It reminds me of what the salesman that sold me the wooden kayak paddle said. >>If you like the natural feel of wood, it is the paddle for you.<<
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konajoe



Joined: 28 Feb 2010
Posts: 177

PostPosted: Thu Oct 25, 2012 11:00 am    Post subject: Reply with quote

The idea that a no-cam sail pumps better than a similar cam sail is ridiculous. The no cam sail is 'easier' to pump, but you don't get as much pressure on the fin. And when I say 'easier to pump', I mean easier to move through the air, just like it would be 'easier' to move a flexible paddle through the water. Flexible mountain bike suspensions, flexible paddles, and flexible rigs are energy sinks. (Lisa, in this house, we obey the laws of thermodynamics. Homer Simpson)

I'm not trying to convince any of you great sailors out there to pump. But for you newbs, who are trying to decide what kind of sails to get, here are some of the advantages of being able to pump effectively.

When racing in marginal conditions (either seriously or casually), getting on a rail or on a plane is everything. If no one is on a rail or a plane, you're gaining or losing ground an inch at time. The first person to pump up will instantly start gaining yards.

Like a power boat, the amount of energy to get a board planing is much more than the amount required to keep it planing. So, a rig that pumps well can really be a big advantage. Lots of folks have been saying 'just rig a bigger sail'. When there's a half hour of daylight left, it's not really an option. The more rigid cammed sails will keep you out on the water longer because you can pump them onto a plane easier in those marginal conditions. The camless sails just deform.

I know you can't teach an old dog new tricks. But for you newbs who don't have any preconceived notions, pump your camless sail on land with a little outhaul and lots of outhaul, and feel the difference in resistence.
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isobars



Joined: 12 Dec 1999
Posts: 14310

PostPosted: Thu Oct 25, 2012 11:42 am    Post subject: Reply with quote

Now that Konajoe is using his thread to try to persuade newbs that cams are inherently the right choice rather than an option, it's only fair to reiterate that there are MANY more criteria in this dilemma than early planing. We need a little balance here, as Puffin, I, and some others, are trying to maintain. If this were merely about a $110 fin, we wouldn't flog it (publicly) so hard, but with a $3,000 quiver, jibing progress, waterstarting, even a novice's assessment of and very continuation of the sport all at stake, the whole picture is important and exceeds the simple sum of its parts, especially this one part.

Just one more example: I deliberately rig a bigger RAF before I go out for that post-sunset session. I'd rather plan ahead than rely on cams to wring that last sesh out of the dying day.


Last edited by isobars on Thu Oct 25, 2012 2:03 pm; edited 1 time in total
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GURGLETROUSERS



Joined: 30 Dec 2009
Posts: 1363

PostPosted: Thu Oct 25, 2012 11:52 am    Post subject: Reply with quote

Konajoe. Paddle efficiency (kayaks) has been extensively studied for years, yet arguments still rage. Same with 'rowing' sails through the air.

In short, the less turbulence created by a paddle stroke in water, the more efficiently it will transfer the force to forward movement. Assuming blade size and shape and shaft length are accurately matched to speed and power applied, a degree of flex in the shaft (regardless of theoretical losses) produces, for most, the best efficiency.

I find pumping a rotational sail with lose or even floppy leach, to work in a similar matter. The 'spring' makes the sail feel less turbulent and more 'geared'pumping up onto the plane than the more rigid cammed sail.

Whatever the theory, it probably boils down to what a person is accustomed to, and can work effectively. For me, that's rotational!
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cgoudie1



Joined: 10 Apr 2006
Posts: 1274
Location: Killer Sturgeon Cove

PostPosted: Thu Oct 25, 2012 12:16 pm    Post subject: Reply with quote

Hmmm, heat transfer and entropy notwithstanding, it's more efficient
for me to pump a no-cam onto a plane. Of course, now that I understand
about all this energy loss, I'm running out and buy (no, better yet design)
a totally rigid mast, I mean one with no deflection at all. I'm sure that'll
help my pumping efficiency (not to mention my sailing once planed).

;*)

-Craig

konajoe wrote:
The idea that a no-cam sail pumps better than a similar cam sail is ridiculous. Flexible mountain bike suspensions, flexible paddles, and flexible rigs are energy sinks. (Lisa, in this house, we obey the laws of thermodynamics. Homer Simpson)


The more rigid cammed sails will keep you out on the water longer because you can pump them onto a plane easier in those marginal conditions. The camless sails just deform.

.
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isobars



Joined: 12 Dec 1999
Posts: 14310

PostPosted: Thu Oct 25, 2012 1:06 pm    Post subject: Reply with quote

cgoudie1 wrote:
I'm running out and buy (no, better yet design)
a totally rigid mast, I mean one with no deflection at all.

The closest sensation I've experienced to that was sailing a double-luff sail. Its luff sleeve extended WAY back into the sail, darn near to the COE IIRC. It didn't do anything else worth crap, but by God once on a plane nothing would stop it. It felt like I had accidentally hooked into a passing bus bumper and was along for the ride all the way to the next bus stop, regardless of what the wind did or what *I* wanted to do. I'm pretty confident that if I had fallen down and was being dragged by one heel, the dang thing would still be going in its straight line to this day, almost 20 years later (just THINK of all the swell rides and cutbacks and lips on RAFs Id'da missed by now!)
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zirtaeb



Joined: 03 Jul 2009
Posts: 2402

PostPosted: Thu Oct 25, 2012 1:20 pm    Post subject: Reply with quote

Well, them's AEROforce sails, white as they were, seemed to pull pretty hard for pretty long.
But being a GaastraRegionalRider, I don't think I ever got beat by one of those, or more, ever, in any slalom heats. I was using GaastraSpeed/RaceSlaloms.
Now, the new thing, since '04, is a resurgence of the wide sleeve 4 cam sails, but now in different colors. While fast sailors often use them, I find them no faster than a '97 no cam sail, when you factor in size, rider size, boards used, and sail types.
All this mathmatic theory is great for the armchair sailor, but sometimes, we gotta look at what is actually happenning in the water.
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konajoe



Joined: 28 Feb 2010
Posts: 177

PostPosted: Thu Oct 25, 2012 1:58 pm    Post subject: Reply with quote

OK guys. I'm sorry I didn't explicitly say that I agreed with the article when they say that the no cam sail is easier to rig and jibe. The article in question (remember that?) makes claims about early planing and light wind performance that I don't agree with. I wasn't trying to dissect or dispute every part of the article.

For every one of you out there who loves your jumps and jibes and freestyle, there's another who just wants to maximize their time on a plane, and just enjoy going on long straight runs. Article says they should go camless. I started this thread because I disagree.
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swchandler



Joined: 08 Nov 1993
Posts: 5882

PostPosted: Thu Oct 25, 2012 2:36 pm    Post subject: Reply with quote

Just curious konajoe, could enlighten us all by identifying all your different cambered sails, to include the number of cambers and battens on each one? As I pointed earlier, there are cambered sails designed for racing and freeride, and as a result, their performance attributes are very different. It would be good to know where you're really coming from.

As for the article you included as a link in your initial post, I didn't even bother to look at it. I think most of us were offering opinions based on our past experience.
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