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  #1  
Old 02-19-2012, 02:44 PM
hobieflier hobieflier is offline
 
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Canting Bowsprit (on Steroids) Concept/ Workable?

Hi everybody,

I'm currently hoping to build a Westport 25 *beachcat this fall and one of the things I want to incorporate is a canting bowsprit. *The only bowsprits I've ever seen are either short -fixed or canting, or really long and fixed. What I'm thinking is a long canting: to mount the base on the main crossbar below the mast (puts the aft compression load directly where you want it) and have it run out beneath the forward crossbar. There would be basically a traveler on the underside of the forward crossbar thats attached to the bowsprit thus holding it up as well as controlling the side to side cant. So your more Slewing the Tip than canting it. The way I see it, this would let you pull the tack of a screecher (or even a code 0) clear over to the windward bow and into cleaner air! *I don't know exactly how far behind the bows is ideal for a screecher or code 0, but it seems to me that around 6 feet is a reasonable goal to shoot for. Any thoughts?

I also wonder (providing that the whole concept is sound) how much elevation the tip really needs. In pictures I've seen, it's quite high, but I think that may be to get a better angle for the guys.*
If it doesn't require a tube too thick (2 to 3") to do the job, it would be nice if it were unsrayed.


What do you think??

Here is a link to some of the few pics if found of the boat:

http://www.boatersresources.com/bfs_...q24=&q25=&q26=
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  #2  
Old 02-20-2012, 11:36 AM
dstgean dstgean is offline
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The Gougeon's new cat Strings has that feature. There is also an article online about a Woods cat that did that maybe with a traditional spin?

Dan
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Old 02-20-2012, 02:32 PM
teamvmg teamvmg is offline
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Why, is your boat going to be really slow?
On a beachcat, the apparent wind is at 90 degrees when going downwind - no need for canting.
Go and sail an F18 or something like that and you will see.
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Old 02-20-2012, 04:37 PM
hobieflier hobieflier is offline
 
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Hi Dan,

Thanks for the info - its nice to know I didn't think I could have been the first person to have thought of something like this. I haven't been able to find the referances you spoke of, do you have a link handy, Thanks!!

Hi teammgv,

That is something I probably haven't fully considered. The only cat I've owned is an old H-16 I had to piece back together. I had wanted a chute, but I parted with it before I got to trick it out.

Thank for the input!

Roaton
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Old 02-20-2012, 10:55 PM
cavalier mk2 cavalier mk2 is offline
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Woody Brown and Rudy Choy put one on Waikiki Surf in the 1950's.
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  #6  
Old 02-21-2012, 09:29 AM
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Eric Sponberg Eric Sponberg is offline
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Hobie flier,

Really, you don't want to pull the bowsprit to windward, you want to pull it to leeward. I have been able to show in classroom demonstrations that by pulling the bowsprit to leeward, the combination of headsail/mainsail chord line necessarily points further away from the wind, and in order to get it back to a proper angle of attack, you have to turn the boat to windward. That is, setting the bowsprint to leeward, say by X degrees, improves your pointing ability toward the wind by a like amount of degrees. And since the whole point of sailing is to get the hull to sail to windward as closely as possible, this concept is a no-brainer.

It is not a new idea, either, it's been around for decades. But is has been summarily outlawed in racing venues, because most of the design and handicap rules say that you cannot move the tack of any sail while racing.

Eric
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Old 02-21-2012, 10:33 AM
redreuben redreuben is offline
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"But is has been summarily outlawed in racing venues, because most of the design and handicap rules say that you cannot move the tack of any sail while racing."

Hmm how would those rules handle a Balestron rig ?
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Old 02-21-2012, 11:40 AM
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Eric Sponberg Eric Sponberg is offline
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Quote:
Originally Posted by redreuben View Post
"But is has been summarily outlawed in racing venues, because most of the design and handicap rules say that you cannot move the tack of any sail while racing."

Hmm how would those rules handle a Balestron rig ?
Probably not allow it, both because of the moving tack, and also because the mast rotates--rotating masts are not allowed either. And these prohibitions are not there because such features are not efficient, quite the contrary--they greatly increase efficiency, and therefore are deemed unfair advantages compared to the rest of the fleet. When a rotating mast was first introduced by L. Francis Herreshoff in 1925 in some NYYC races that year, it was immediately outlawed by the regatta committee as being an unfair advantage. His R-boat design Live Yankee also sported a mast that was practically free-standing, having no headstay, intermediate shrouds, upper shrouds, or backstays. It was also fitted with a spar forestay.

These prohibitions have remained in many (not all) design and handicap rules ever since, mostly by pure inertia, ignorance, and industry pressure to maintain the status quo of conventional boat design and hardware.

Eric
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Old 02-21-2012, 11:59 AM
teamvmg teamvmg is offline
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Quote:
Originally Posted by Eric Sponberg View Post
Hobie flier,

. And since the whole point of sailing is to get the hull to sail to windward as closely as possible, this concept is a no-brainer.



Eric
I think he is try to sail DOWNWIND!
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  #10  
Old 02-21-2012, 12:10 PM
hobieflier hobieflier is offline
 
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I just want to sail faster - in all directions! I hadn't considered the effects of moving it to leeward while pointing - I just assumed windward was better but now that I visualize it, it makes perfect sense.

Thanks Eric,
Thanks All,

Roston
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  #11  
Old 02-21-2012, 12:27 PM
Stumble Stumble is offline
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Eric,

While I normally agree with you, when flying a spinnaker off of an articulating spinnaker you do want to pull it to windward. This allows you to sail deeper with the sail set, though I am only familure with racing boats that do this.

As for phrf issues. The Melges 30 actually used an articulating sprint, and is generally rated without limitation, it just has to be part of the normal set up of the boat.
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  #12  
Old 02-21-2012, 12:29 PM
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Eric Sponberg Eric Sponberg is offline
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Actually, when sailing on the wind, you should have the bowsprit to leeward, and then as you fall off, you want to move it gradually over to windward. Then, when sailing on a broad reach or a run, you want the bowsprit fully over to the windward side.

Eric
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