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how to lift Isotope cat off trailer advice needed
by RobertHandyman. 02/04/23 11:48 AM
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Re: Onboard video from Tradewinds [Re: Jeff.Dusek] #242849
01/23/12 10:58 AM
01/23/12 10:58 AM
Joined: Aug 2006
Posts: 297
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rexdenton Offline
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Jeff, can you do me a favor? I am re-fitting standing rig this year, and had thought of going to a similar configuration. My thought was to swage a ring, or pigtail on the port shroud. My boat is totally apart and I cannot measure the ideal placement of the ring on the shroud. Can you measure and let me know how high, as measured from the attachment point on the deck, to the location of the block as it is mounted on the shroud? I would be much in your debt for doing so. Rex


Nacra F18 #856
-- Have You Seen This? --
Re: Onboard video from Tradewinds [Re: Jeff.Dusek] #242850
01/23/12 11:05 AM
01/23/12 11:05 AM
Joined: Jan 2007
Posts: 139
Hernando, Florida
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Mlcreek Offline
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Mlcreek  Offline
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Hernando, Florida
What is the purpose for pulling the board...less drag?
Thanks



Forrest
I-20
USA 645

" There ain't enough rum in the drum!"
Re: Onboard video from Tradewinds [Re: Mlcreek] #242852
01/23/12 11:18 AM
01/23/12 11:18 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
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Joined: Jun 2001
Posts: 12,310
South Carolina
Originally Posted by Mlcreek
What is the purpose for pulling the board...less drag?
Thanks



Yup. It helps make the boat more slippery downwind. You still want enough board in that the boat mostly travels in a straight line (it's faster that way) and to ensure that you have enough bite in the water to fly a hull...but you're aren't too concerned about maintaining height since you're object is usually further downwind from your angle (so deeper is better). The boards present a good bit of drag - enough that you can feel the difference up vs. down...so up enough to maintain straight travel downwind but reduce drag.


Jake Kohl
Re: Onboard video from Tradewinds [Re: Jake] #242858
01/23/12 12:43 PM
01/23/12 12:43 PM
Joined: Jan 2007
Posts: 139
Hernando, Florida
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Mlcreek Offline
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Hernando, Florida
Thanks Jake,

Is one side better than the other? Also, if the boards are drags, and to far down cause you to trip in other conditions, then why are they so long, and in some cases longer? Other than Mike's foils for lifting, can they be to long?
Thanks again

Forrest I-20


Forrest
I-20
USA 645

" There ain't enough rum in the drum!"
Re: Onboard video from Tradewinds [Re: mikekrantz] #242859
01/23/12 12:55 PM
01/23/12 12:55 PM
Joined: Jan 2005
Posts: 6,049
Sebring, Florida.
Timbo Offline
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Timbo  Offline
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Posts: 6,049
Sebring, Florida.
Deeper boards = more lift when going upwind, and will fly the hull quicker, so in light air, full down, and as the wind picks up and you don't need all that lift, you start to pull them up.


Blade F16
#777
Re: Onboard video from Tradewinds [Re: Mlcreek] #242862
01/23/12 01:25 PM
01/23/12 01:25 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
Originally Posted by Mlcreek
Thanks Jake,

Is one side better than the other? Also, if the boards are drags, and to far down cause you to trip in other conditions, then why are they so long, and in some cases longer? Other than Mike's foils for lifting, can they be to long?
Thanks again

Forrest I-20


We lift both when possible - but the leeward board is more important...sometimes, if time doesn't present itself, we lift only the leeward board and get the other one on the next gybe.

It was blowing about 15 to 18 in those races. If you can see it in the video, we had our boards raised about 8 or 10" upwind too. The boat carries enough speed at those wind strengths that the boards are more effective and we didn't need all that board grip in the water...not only does it reduce the drag, but it helps to settle the boat down just a little by raising the center of lift and making the boat a little less tippy.

As to the perfect aspect ratio - I have no idea. Over the last 15 years, we've seen boards continue to get skinnier and longer. The latest F18 boards are over 6 feet long. The A-cat boards have also seen the same trend (until the last couple of years where the a-cat boards are all banana shaped). The trick is a compromise between slow speed handling (pre-start) and efficiency at speed. Longer narrower shapes (like an airplane glider) are better at producing efficient lift. Materials have mostly driven the aspect ratio of our foils - which is why we're seeing them become thinner and longer lately (more advanced use of carbon). I'm sure there's a point in there where high aspect ratio becomes a problem...but I can't image where that is.


Jake Kohl
Re: Onboard video from Tradewinds [Re: Jake] #242872
01/23/12 03:34 PM
01/23/12 03:34 PM
Joined: Dec 2001
Posts: 5,590
Naples, FL
waterbug_wpb Offline
Carpal Tunnel
waterbug_wpb  Offline
Carpal Tunnel

Joined: Dec 2001
Posts: 5,590
Naples, FL
How high up do your boards go with the up-fker? about half-way?

I like the system you describe (especially if someone besides the crew can do it, in case hoisting the spin takes more than 1/2 second), and the other suggestion about swaging a ring/block on the shroud with a purchase system under the tramp sounds very effective.


Jay

Re: Onboard video from Tradewinds [Re: waterbug_wpb] #242876
01/23/12 03:46 PM
01/23/12 03:46 PM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
I believe they come up slightly short of half way (with the older, slightly shorter, infusion boards). The distance the line can go down into the trunk is limited by the depth of the hull...the line shouldn't protrude outside of the daggerboard trunk when the board is down all the way. This is really the limitation.


Jake Kohl
Re: Onboard video from Tradewinds [Re: mikekrantz] #242878
01/23/12 03:51 PM
01/23/12 03:51 PM
Joined: Sep 2004
Posts: 2,584
+31NL
Tony_F18 Offline
Carpal Tunnel
Tony_F18  Offline
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Joined: Sep 2004
Posts: 2,584
+31NL
With the new Infusion Mk2 boards you have to hoist them with a block on the shrouds otherwise they wont come up far enough.

Re: Onboard video from Tradewinds [Re: rexdenton] #242889
01/23/12 05:40 PM
01/23/12 05:40 PM
Joined: Nov 2011
Posts: 554
Boston, Ma
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Jeff.Dusek Offline
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Jeff.Dusek  Offline
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Joined: Nov 2011
Posts: 554
Boston, Ma
Originally Posted by rexdenton
Jeff, can you do me a favor? I am re-fitting standing rig this year, and had thought of going to a similar configuration. My thought was to swage a ring, or pigtail on the port shroud. My boat is totally apart and I cannot measure the ideal placement of the ring on the shroud. Can you measure and let me know how high, as measured from the attachment point on the deck, to the location of the block as it is mounted on the shroud? I would be much in your debt for doing so. Rex


Rex,

I am in Singapore until March 3rd, so away from my boat. I can check with the Fiancee and see if she can pull the shrouds out to measure. Also, I am sailing the Thai Cat week in February, so I can try to measure there if someone has the same system.


USF18 Eastern Area Rep
Nacra Infusion USA 753
Re: Onboard video from Tradewinds [Re: Jeff.Dusek] #242897
01/23/12 09:59 PM
01/23/12 09:59 PM
Joined: Apr 2008
Posts: 235
JJ_ Offline
enthusiast
JJ_  Offline
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Joined: Apr 2008
Posts: 235
The way the boat jets off when the spinnaker is set!Worth watching all day...

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