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Old Nov 06, 2013, 08:00 AM
OlivierFRA100
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170 Posts
Quote:
Originally Posted by basildog View Post
FWAL your comments about fin position is interesting. In Australia Tim Brown built Pikantos with Mark Paterson fin and rig positions are well known to be very quick. I understand they are only a few millimetres different from Graham Bantocks measurements.

.
I can also say that CRO Pikantos have a fin position different of Sails etc ones. And were faster IMHO.
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Old Nov 06, 2013, 11:08 AM
Registered User
Canada, BC, Campbell River
Joined Oct 2012
51 Posts
OK First question. Other than balance (which can also be achieved by moving the mast) what effect does moving the fin have? Is there any drag benefits? Does it make the boat track better? I can't see it making the boat faster. Any ideas?
Don
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Old Nov 06, 2013, 11:49 AM
OlivierFRA100
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Joined Nov 2006
170 Posts
In CRO Pikantos it was balance. Boat was easyer to sail and tune.
And it's by far easyer to move fin than mast on an existing mold...
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Old Nov 06, 2013, 03:00 PM
Love RC Yachts!!!
Australia, VIC, Melbourne
Joined Aug 2012
163 Posts
From what I understand, if the keel moves further aft, relative to the mast, the boat tends to be quicker downwind, but harder to tack upwind when hard pressed. I believe Jeff Byerley found this out with his early IOM designs....

I am told Tim Brown moved both the mast and keel aft on th Pikanto to help alleviate nose diving problems downwind, as well as carrying a decent amount of mast rake on the Mark Paterson rig setup....

On the other hand, Craig Smiths Obsession and Fusion carry the keel further forward than other designs, and work just fine.

Interested in he logic of aligning CE of the keel with the CLR. Makes sense though, with the rudder then determining balance. I have found rudder length makes a noticeable difference to the balance. Cutting 25mm off made the boat more responsive to lifts, and thus more sensitive to rake. Had to move rake forward one hole to re balance it. All my boats ( including 10R and Marblehead) all use Craig Smith rudders....
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Old Nov 06, 2013, 03:14 PM
David Cook Victoria, BC Canada
Joined Oct 2012
246 Posts
Quote:
Originally Posted by Don Case View Post
OK First question. Other than balance (which can also be achieved by moving the mast) what effect does moving the fin have? Is there any drag benefits? Does it make the boat track better? I can't see it making the boat faster. Any ideas?
Don
I was taught moving the fin forward is the same as moving the mast aft creating weatherhelm. A boat may not go through the water any faster but if leeway (lateral hull sliding off away from the wind) is reduced then there are huge gains going to windward.
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Old Nov 06, 2013, 08:00 PM
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United States, ME, Bar Harbor
Joined Nov 2013
11 Posts
Sounds like Bigpat knows what he's talking about. I think we need him on the next Americas Cup campaign to ensure it stays in the U.S.A.
Very surprised he hasn't been picked up by one of the teams. What is he doing sailing toy boats???
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Old Nov 06, 2013, 11:28 PM
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Perth Western Australia
Joined Jul 2009
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Originally Posted by Tractors R Us View Post
Sounds like Bigpat knows what he's talking about. I think we need him on the next Americas Cup campaign to ensure it stays in the U.S.A.
Very surprised he hasn't been picked up by one of the teams. What is he doing sailing toy boats???
Wasn't there enough aussies on the oracle team

Sorry Porky couldn't resist that one, know back to the design discussion.
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Old Nov 07, 2013, 03:10 AM
Useful Idiot
Asturias, Spain
Joined Mar 2001
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Originally Posted by 8387mike View Post
Wasn't there enough aussies on the oracle team
Even the Aussies weren't doing much until a Brit got called in to whip them into order.
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Old Nov 07, 2013, 02:16 PM
NORTHLAND NEW ZEALAND
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New Zealand, Northland, Totara North
Joined Feb 2012
566 Posts
With a very aft CLR and CE, the CG goes back therefore the CB goes back resulting in very curved aft lines which I personaly dont like as it sucks the stern down. This is good for preventing nose diving but has a negative Impact on speed
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Old Nov 07, 2013, 03:09 PM
David Cook Victoria, BC Canada
Joined Oct 2012
246 Posts
Today we laid up the 1st half of the female mold for PP6. Lots of tight inside corners. I'll be praying that it separates from the form. Will wait for a week, separate, wax, PVA and lay up the 2nd half the following week
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Old Nov 07, 2013, 04:13 PM
NORTHLAND NEW ZEALAND
D design's Avatar
New Zealand, Northland, Totara North
Joined Feb 2012
566 Posts
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Originally Posted by PorkyPig View Post
Today we laid up the 1st half of the female mold for PP6. Lots of tight inside corners. I'll be praying that it separates from the form. Will wait for a week, separate, wax, PVA and lay up the 2nd half the following week
Looks like fun!
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Old Nov 07, 2013, 06:02 PM
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United Kingdom, London
Joined Jun 2005
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are you using chopped strand mat?
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Old Nov 07, 2013, 07:32 PM
David Cook Victoria, BC Canada
Joined Oct 2012
246 Posts
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Originally Posted by ToniGe23 View Post
are you using chopped strand mat?
yes, chopped matting that comes in sheets (not the blown in stuff)

first 2 layers are 1 oz. and next 2 1.5 oz...

2 layers of regular gelcoat (molding gelcoat is too expensive and you can't buy it in small quantities)

Here's a little tip. the f/g guru whose shop we used said
most problems people have with gelcoating is they don't make the mix hot enough.

Smelling up his shop rather than our house is good for my marriage
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Old Nov 07, 2013, 08:24 PM
Love RC Yachts!!!
Australia, VIC, Melbourne
Joined Aug 2012
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Quote:
Originally Posted by D design View Post
With a very aft CLR and CE, the CG goes back therefore the CB goes back resulting in very curved aft lines which I personaly dont like as it sucks the stern down. This is good for preventing nose diving but has a negative Impact on speed
Do mean in terms of rocker line only? I When playing on the PC, I too have tried to use straight exit angles, between 10 & 12 degrees. You recommend also straighter runs aft all the way up to the waterline too?

BTW, I'm just a rookie at this sailing game, but if I had to choose, I'd have to be patriotic and back the Aussie AC challenge!!!!
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Old Nov 07, 2013, 11:15 PM
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Perth Western Australia
Joined Jul 2009
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Originally Posted by bigpat View Post

BTW, I'm just a rookie at this sailing game, but if I had to choose, I'd have to be patriotic and back the Aussie AC challenge!!!!
Thats the way Pat help the Oatley boys, go the Aussies
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