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08-04-2007, 16:35
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#1
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Registered User
Join Date: Aug 2006
Location: cairns australia
Boat: now floating easy37
Posts: 636
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interesting idea
Revisiting a Mast-Aft Sailing Rig
i know at the moment bold and adventuring catamaran builders and designers are finally looking outside the box and think of things like biplane rigs to lower centre of effort/ make sails more handleable but hows this for interesting
sean
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08-04-2007, 17:05
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#2
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Registered User
Join Date: Mar 2006
Posts: 402
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it does look interesting, but i'd like to see how it stands up to sea time before I'd trust it on my boat.
also while the article says large mainsails are hard to deal with, it seems like large headsails would be even more dangerous
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08-04-2007, 17:50
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#3
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Registered User
Join Date: Aug 2006
Location: cairns australia
Boat: now floating easy37
Posts: 636
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i guess you'ld roller furl them, i knew mains lost a bit of power due to the mast but i had no idea it was between 1-2 ft on my boat thats between 3.3-6.6 m2
sean
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09-04-2007, 10:04
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#4
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CF Adviser Moderator Emeritus
Join Date: Dec 2006
Location: Montrose, Colorado
Posts: 9,845
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Great post, northerncat . . .
. . . and I'd like to see someone construct a proof-of-concept vessel to see how theory compares to reality.
TaoJones
__________________
"Your vision becomes clear only when you look into your own heart. Who looks outside, dreams; who looks within, awakens."
Carl Gustav Jung (1875-1961)
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01-05-2007, 21:51
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#5
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Registered User
Join Date: Apr 2007
Location: SoCal
Boat: In the market
Posts: 173
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Delta sail rig
The first Kantola trimaran I ever saw had the exact rig you guys are talking about. The boat was called "EZ Glider" and its owner said he was very happy with the way it sailed.
__________________
Robert
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02-05-2007, 04:55
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#6
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Registered User
Join Date: Nov 2005
Location: At the intersection of here & there
Boat: 47' Olympic Adventure
Posts: 4,851
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While I like the "mast-aft rig", my preference is a bi-pod (A-frame) arrangement, as seen here: SMG-Multihull - sail the difference
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02-05-2007, 06:01
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#8
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Registered User
Join Date: Apr 2007
Location: SoCal
Boat: In the market
Posts: 173
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A Frame and Kite
Lode: In the late 80s early 90s there was a monohull that was built and rigged by a group of manufacturers that was used for boatshow and print advertising that went by the name "Halcyon". It had the A frame rig like the one you mentioned It also was the first boat that had seen that was designed with the organic sweeping cabin top and windows. Ahead of its time and very pretty.
Gord: What I like about the Traction Kite rig is that it is easily retrofitted and does not take a lot of gear to control. There was a site that talked about a lighter than air Kite that had a helium filled leading surface that kept it aloft out of the water.
Both systems are great ideas IMO.
__________________
Robert
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04-05-2007, 20:02
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#9
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Registered User
Join Date: Nov 2005
Location: At the intersection of here & there
Boat: 47' Olympic Adventure
Posts: 4,851
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Rob,
I've seen pictures of Halcyon, and agree she's an attractive yacht. Here's another with a discussion about the rig: Home
Kevin
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04-05-2007, 20:29
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#10
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Registered User
Join Date: Apr 2007
Location: SoCal
Boat: In the market
Posts: 173
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A Frame Rig
Hy Kevin, that Kolika is a very crafty boat. The rig is pretty much as I remember seeing on Halcyon. Did you check out the rudder? It is balanced and has the trim tab trailing edge. I have never seen the alternating vents like that. Kort nozzle too. Lotsa thought went into that boat.
Rob
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Robert
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05-05-2007, 09:46
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#11
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Registered User
Join Date: Oct 2005
Posts: 346
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northerncat
you should check out Brian's latest rig on his website:
DynaRig MotorSailer
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05-05-2007, 12:10
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#12
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Registered User
Join Date: Mar 2003
Location: Philippines in the winters
Boat: It’s in French Polynesia now
Posts: 11,368
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mast-aft rig
There is a monohull with a Ketch rig set up this way in Friday Harbor, WA. I haven't seen it out-N-about but it has a double roller reefing on the fore mast and a single roller reefing on the aft mast.
The disadvantages I see are the extreme beefing up of the (backstay) shroud chainplates. The stresses of holding a mast at such an angle, and then adding some forestays, would be tremendous in a rough sea.
I liked the idea years ago when I first seen it but the structure of the hull would definitely be in question if one were to go with this rig. The one in Friday Harbor is a steel hull. I knew I should have taken pictures.
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18-06-2016, 09:28
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#14
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Marine Service Provider
Join Date: Aug 2007
Location: St Augustine, FL, Thailand
Boat: 65 Sailing/Fishing catamaran
Posts: 1,156
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Re: interesting idea
Just ran into this discussion from quite some time ago. Thought I would update it just a bit with a very interesting CFD & Wind Tunnel study carried out on an aft-mast sail rig.
Wind tunnel and CFD investigation of unconventional aftmast rigs
Aftmast rigs??? - Page 52 - Boat Design Forums
Quote:
Both experimental tests and VPP calculation show that the double jib configuration with overlap gives the best performance and also the same configuration without overlap gives better results in comparison with the standard sloop solution.
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__________________
Brian Eiland
distinctive exploration yachts
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18-06-2016, 18:00
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#15
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Registered User
Join Date: Jan 2014
Location: Coffs Harbour, NSW
Boat: FreeFlow 50 cat
Posts: 1,336
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Re: Great post, northerncat . . .
Quote:
Originally Posted by TaoJones
. . . and I'd like to see someone construct a proof-of-concept vessel to see how theory compares to reality.
TaoJones
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Here ya go:
FreeFlow Catamarans
Built 2010 with aft mast and wishbone reverse vang for performance. Keshi has sailed around Australia since then in some very challenging conditions on all points of sail. It sails beautifully as I can attest to personally, having test sailed her.
Big advantages in sail handling for shorthanded crew or singlehanded ( the owner is in his mid 70's and single hands usually), light air performance, and balance working to weather.
FYI, Lagoon designers VPLP saw a 52 foot FreeFlow sister ship being built in China and closely examined the aft mast engineering. Just co-incidentally (ha ha ha) the Lagoon 52 & 39 appeared thereafter. You would not know this from reading their marketing blabla, of course. It is all due to their "innovation".
But there are some aft mast implementations that have not considered the support engineering considerations well enough, let's put it that way.
You may also want to consider the performance aspects and look up how many performance sailing craft are using reverse vang configuration.
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