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AC 75 Now Afloat

Posted: Sun Sep 08, 2019 12:02 pm
by John Perry
Well, the first AC 75 is now afloat, there are a few videos on the internet, e.g. https://www.youtube.com/watch?v=VuI1ILwo7tI

When we first saw the concept I expect that some of us wondered if it would even stay upright in a flat calm. Well I expect it will but we still dont have confirmation of that since there is not yet a mast on the boat.

We should know soon if this is a viable new concept for a yacht race, or a disaster. The small scale test boats did appear to work very well, at least under the conditions for which video has been released. Reading between the lines of recent announcements there is still some uncertainty about low speed manourves. Grant Dalton himself said at launch 'this is a boat that is either in the water stopped, or its up and going' Yes, but it has to somehow get from that first situation to the second, if necessary under difficult weather conditions and under pressure from a competing boat. All very interesting.

Re: AC 75 Now Afloat

Posted: Wed Sep 25, 2019 10:34 pm
by John Perry
Two AC 75's now launched and sailed for the first time!

This is the AC75 'Defiant, from the American Magic AC cup team, I think the very first video to come into the public domain:
https://www.youtube.com/watch?v=-43qV_U9biY

Pretty well rock steady, even foiling through a gybe. Amazing for a first sail with a totally new design concept.

Then, a few days later (I think) the New Zealand AC 75 'Te Aihe' sailed for the first time - as far as I can tell no video has yet been released but a few pictures are here:
https://livesaildie.com/emirates-team-n ... 5-te-aihe/

Re: AC 75 Now Afloat

Posted: Wed Mar 11, 2020 7:46 am
by Gigliobianco52+
dear John Perry, I found very interesting your article about towing a boat; I'd like to the wetted surface of the boat and the friction coefficient you got from the formula: resisting force= 0.5 mass density of water x wetted surface x speed squared x friction coefficient
many thanks
giuseppe gigliobianco
g.gigliobianco@fastpiu.it

Re: towing

Posted: Thu Mar 12, 2020 8:25 am
by Gigliobianco52+
dear John Perry, I found very interesting your article about towing a boat; I'd like to the wetted surface of the boat and the friction coefficient you got from the formula: resisting force= 0.5 mass density of water x wetted surface x speed squared x friction coefficient
many thanks
giuseppe gigliobianco
g.gigliobianco@fastpiu.it