Author Topic: Boat speed  (Read 3931 times)

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Boat speed
« on: April 08, 2014, 07:15:16 AM »
Roger Parish
   
Posted on Saturday, November 24, 2007 - 08:55 pm:      
The latest posting by Geoffrey quoting boat speeds reminded me of a discussion I have had with Dave Cawston this year on how fast can a Winkle Brig go. I have often seen speeds in excess of 5Knts on my log but it is probably inaccurate. Wave making theory limits a displacement's boat speed to 1.34xsq rt of the water line length. For a cruising boat the factor is below 1.2. This would indicate that the maximum hull speed for a Brig is < 5Knts. All of this would be irrelevent if the boat starts planing! How fast is your Winkle Brig?

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Re: Boat speed
« Reply #1 on: April 08, 2014, 07:15:33 AM »

Adrian Evans
   
Posted on Sunday, November 25, 2007 - 11:25 pm:      
a little while back, doing some fairly in depth surfing, I came across a pdf Portsmouth yardstick, listing, IIRC, a hull speed for the winklebrig of 5.13 Knots.

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Re: Boat speed
« Reply #2 on: April 08, 2014, 07:15:47 AM »

Adrian Evans
   
Posted on Monday, November 26, 2007 - 12:52 am:      
found this reference
http://www.byronsoftware.org.uk/bycn/by05011.htm
that gives 5.19 Knots. can't find the other.

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Re: Boat speed
« Reply #3 on: April 08, 2014, 07:16:02 AM »

Julian Swindell
   
Posted on Monday, November 26, 2007 - 02:19 pm:      
I once checked the "max speed" section on my GPS unit after I had put the boat back in the Yard. 14 knots!! Then I remebered that I had left the unit turned on as I towed the boat back into the yard... I do get the occassion 5.9-6.0 knots reading but that is always suspect (current, sliding down a wave etc.) The most common GPS max is about 5, but really 3 is pretty good.

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Re: Boat speed
« Reply #4 on: April 08, 2014, 07:16:20 AM »
David_owens
Username: David_owens

Registered: 04-2010
   
Posted on Wednesday, May 30, 2012 - 08:02 pm:      
At the risk of being laughed to scorn, is there any more information on the PY number for a Winkle Brig? The above Byron Software quotes 1116, a more recent version quotes 1114. No doubt this difference is critical. The reason for this request is that the Bristol Channel Area of the Old Gaffer's Association has decided to hold a Gaffers Race as part of the Cardiff Bay Club's regatta, and the CBYC has forms and protocols ... As Secretary of the BCA I must show willing even though I'd rather take Puffin fishing.
Also, can anyone help advise on how best to cheat on a Winkle Brig , so that we don't come last :-)

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Re: Boat speed
« Reply #5 on: April 08, 2014, 07:16:35 AM »

Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Thursday, May 31, 2012 - 07:29 am:      
When racing, I find the most useful sail in my locker is the iron topsail.

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Re: Boat speed
« Reply #6 on: April 08, 2014, 07:16:50 AM »

David_owens
Username: David_owens

Registered: 04-2010
   
Posted on Sunday, June 03, 2012 - 02:11 pm:      
Martin. Really. Shame on you. But I guess with the engine obscured from sight in the well, one might just get away with it... Ho hum :-)