A Class World Championship 2015 German Championship 2009 A-Class Worlds 2011 A-Class Winter Series ETNZ: A-Class Arms Race A-Class Worlds A-Class Worlds - Practice Race 2014 A-Class Worlds: Nathan Outteridge explains foiling A-Class Worlds Practice Race A-Class Worlds 2014 BBR Final 2015 Worlds DNA A-Class Flyer II Ashby Sails A-Class Worlds Sanguinet Clarksail One on ONe with Nathan OUtteridge at 2012 Worlds Clarksail One on One with Mischa Heemsker after 2012 Worlds ClarkSail One on One with Andrew Landenberger ClarkSail One on One with Simon McKeon ClarkSail One on One with Steve Brewin Long Beach A-Class Catamarans

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1 month ago

New fleet - Keuka Lake, NY.

We have a good sized MC-Scow fleet but there are a few of us that are ready to jump to a new boat, something a little more fun when you round the windward mark. Three of

We are all E-Scow, MC-Scow and iceboat types, some with more experience than others. We understand apparent wind sailing. But as none of us sail on a wire now, we are thinking we should start by not foiling and build into that.

So we are looking for boats that are fast classic boats, moderately priced, and with the bits and pieces you need when you start a program like trailers and covers. If you are ready to upgrade to foiling and want to sell your floater, please give us a call. I can be the starting point of contact.

Chris Hawk 585-727-5363

P.S. Someone should really remove all the sold boats from the classified page. ... See more

1 month ago

Foiling Week

New A-class design.

1 month ago

Modern Man

We never found the clip we truly wanted to show on the Independence Day, the 4th of July, for the USA. So, belated, this will have to do. Hope everyone around the world had a good day on the 4th of ... See more

Coworker : "What are you doing for the fourth?"
Me :

Via: Freedom Hard

1 month ago

Half year gone already... Is your luck the way you expected it? Or you have achieved something and you need to protect it?? Dr. Musitwa M Gerald on wats app +27633654942

1 month ago

Watsapp no. +27633654942
We have the best spells all around... We go to those places more so the spirits from Gold mines and we the richest spirits to enhance all our spells in as far as wealthy is ... See more

1 month ago

America's Cup - Vodafone Dock-In Show - Stories that can now be told

Congrats from the USA A Class Association to Emirates Team New Zealand on innovation and sailing excellence.

Love the inside scoop from Grant Dalton here on broken daggerboards, repairs, etc. ... See more

Peter Lester and Martin Tasker set up an interviewing position inside the Emirates Team New Zealand base during the post-America's Cup celebrations, and got some of the key players to let a few cats ... See more

2 months ago

Sailing Anarchy

Good info and innuendo on the ground in Bermuda today from Sailing Anarchy

It's the America's Cup morning report from Alan Block on location in Bermuda. Get the exclusive inside stuff from Mr. clean! Emirates Team New Zealand ORACLE TEAM USA Bermuda

2 months ago

Ellway Aero-Hydrodynamic Designs

For all the technical sailors out there and everyone who is geeking out on the how behind the America's Cup, here is some detailed thinking on why Emirates Team New Zealand looks so good.

Why have ENZ been dominant so far - Are the kinks in ENZ foils significant?

In the light winds of the 1st weekend’s races of the AC finals, ENZ seemed to be able to sail at the same speed at

Commentator Ken Read has often pointed to the noticeable difference in the front view shapes of the ENZ and Oracle foils – Here I have made a quick analysis of the likely effects. Please note, however, that because I do not have access to any foil geometry details, this has necessarily involved some significant assumptions and guesswork.

Let’s just look at upwind and assume both boats are travelling at the same speed, but with ENZ pointing around 3 deg higher. As a first approximation, ENZ will see an apparent wind angle (AWA) of 3 deg less than Oracle

The AWA is the ‘glide angle’ of the boat. It is the sum of the aerodynamic and hydrodynamic glide angles. The aero glide angle is determined by the ratio of drag to lift force from the rig. It also includes the parasitic drag of the hulls rigging and crew etc.
The hydro drag angle is the ratio of water drag to side force from the rig (Fy) – see fig 1..

So for ENZ to point higher at the same speed implies that either the air L/D is better (eg less drag for same lift) or that ENZ can generate more side force from the available righting moment, or that the foil drag is lower.

a) Foil drag
The foils have to support the total load of the boat (~29 kN inc crew) and also resist the side force Fy from the rig (~11.4kN).
Foil drag can be divided into 2 key components. Induced drag which is produced as a direct consequence of producing lift, and profile drag which is due to the friction of the water acting on the foils.

At low foiling speeds, induced drag dominates. At high speed, profile drag is dominant. At minimum drag, the induced and profile drags are equal – see Fig 2.

ENZ seems to have the greatest advantage in the lower speed range. This suggests that the foil design may generate less induced drag.

I have done some rudimentary CFD based on the observed foil geometries of the 2 boats – see Fig 3. Both foils have the same wetted area and have been designed to have the same lateral CofP (centre of pressure) at 23 kts such that both boats would have similar available righting moments.

As suspected, ENZ foil produces less induced drag. It is also indicated to need less side slip (yaw angle) to generate the required side force. At speeds of 18-20kts, the predicted difference in drag reduces the ENZ hydro drag angle by a about 1 deg maximum. At around 30kts, there’s negligible difference in the predicted drags.

It appears that the distinctive foil shape does provide some gain, especially at lower foil speeds. But this gain does not appear to be large enough to explain all of ENZ’s vmg advantage.

b) Wing trim
The side force Fy is determined by the righting moment (Mx) and the heel arm length – this is the distance between the lateral CofP of the foils and the vertical CofE of the rig.
The CofE can be moved from about 40% rig height down to around 10% by adding more and more twist.

So, by adding more twist, the heel arm is reduced, which increases Fy. This reduces the hydro drag angle. But more twist will usually mean more induced drag from the wing. This increases the aero drag angle. It’s a game of trade-offs and marginal gains – getting it right can make significant differences to upwind vmg.

The base of the wing is at about 2.5m above the water and the tip is about 26m above the water. Vertical wind gradient causes the true wind speed (TWS) at the base of the wing to be lower than that at the tip. Typically, the wind at the tip would be about 25% more than at the wing base. If the boat is sailing in 8kts wind and at a speed of 21kts at 55deg TWA, the effect of the vertical wind gradient is that the apparent wind speed at the tip is now some 35% greater than the base. In addition, the AWA at the tip will also be around 4 deg more than at the base. The increasing AWS and AWA from base to tip require that the wing needs significantly more twist and camber change along its span to obtain optimum loading when compared with the no wind gradient case.

All teams will have computer models to predict the optimum settings for their wing elements for different wind conditions. But the assumptions made in the models may not be the same for one team to another. Further, depending upon the wind direction, the vertical gradient can change markedly due to turbulent mixing. And then there’s the man-machine interface. It is possible that ENZ can control their wing more accurately and rapidly to match varying conditions.

So, my suspicion is that ENZ may be able to trim their wing more effectively to date.

c) Windward heel
I’ve noticed ENZ heel to windward. This will bring the vertical centre of gravity to windward and could add yet more righting moment and thus Fy (see figure 4)

d) Other
The ENZ foil design should be better at high yaw rates during tacks. This, combined with the faster and more accurate control facilitated by having a dedicated foil controller, should be a big advantage.

The foils also enter the water in a more gradual way when deployed, disturbing the boat less.

My analysis suggests that ENZ dominance to date does not stem from one specific design attribute. The distinctive kinked foils do appear to provide less drag at lower foiling speeds. I suspect that the bikes have provided more power availability allowing wing and foils to be more frequently trimmed. Importantly, the bikes have also freed the hands of the sailors. This has allowed complex tasks to be designated to specific crew members.
The wing trimmer and foil controller are looking at displays. I suspect that ENZ have a better man-machine interface which allows finer control of both wing and foils.

Is it all over for Oracle? Well not necessarily if the wing trim is the main issue. And I really hope for more of a competitive sporting contest in the upcoming races. But ENZ have both Ray Davies and the foil Kinks. I fear that if the weekend forecast proves correct, they may well preside over a Waterloo Sunset for Oracle. ... See more

2 months ago

The Kiwis’ Edge in America’s Cup: Drones

Nick Bowers has played a big role in growing our fleet and we look forward to continuing to work with him. Special thanks to RatherBe Sailing and Christine Burns Reiss and Panama City, Florida among ... See more

Nick Bowers uses drones to shoot spectacular sailing footage, which earned him a place with innovative Team New Zealand, an America’s Cup finalist.

2 months ago

San Diego Yacht Club

Registration is now open for the 2017 A Cat North American Championship hosted by San Diego Yacht Club this October!

San Diego Yacht Club - to encourage and foster interest in all aspects of yachting.

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