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America's Cup Blog

A word about wing trim trial and error


Emirates Team New Zealand wing trimmer Glenn Ashby recalls only one anxious moment while sailing the AC72.

It was the time a squall hit them on Auckland Harbour just as they were  about to round North Head.

“We had been in squalls before but never when we either had to tack the boat or commit to bearing away. We were in close to 30 knots true wind speed.

“It’s the only time I remember when we thought ‘uh, uh got a bit on here’ but other than that life with the AC72 has been just fine.”

The strongest breeze they’ve had at the mast head is about 33 knots with a good 25 to 28 knots on the water at times. “We have had 60 knots of apparent wind across the deck so there can be a lot of wind noise which affects communications. That’s a key area to get right.

“We are just going to keep getting faster and faster and faster. We’re pushing the limits structurally when sailing on the edge but we do have to be able to sail these boats in San Francisco conditions. Hopefully we’ve got a package that’s going to suit those conditions very well.

The team has pushed the boat in a seaway of just over a metre. “It’s not overly comfortable but the boat’s fine – no issues at all.”

Glenn can see the day when the crew will have no worries about racing around a short and confined America’s Cup course.

“Early on we thought we would have plenty on getting the 72 round the track but after having sailed for 16 days we can see the boats will be very manageable..

“But I believe the racing will still be tough in big breeze – but there’s no doubt the boats will be very sailable and manageable in high wind speeds.”

Ashby described his typical sailing day: “My role is to trim the wing to a set of pre determined targets while also using judgement to manipulate shapes to achieve the mode that the boat requires.

“It’s   bit of a juggle between setting the wing up to match the parameters set by the designers with how the boat is being sailed at any given time.

“The 72 wings are a step up in design and flexibility compared to the AC45. For me it’s  less of a physical role, compared with the 45,  because the grinders do a lot of the work.

The aim is to learn every time we sail – new stuff about the wing and about the boat in general. There’s still a lot to learn but we’re more comfortable with the boat now.

“We want to keep learning and incorporate what we have learned into wing 2.”

Foiling with the wing does definitely change things. “We’ve found we have to change the wing trim quite aggressively from when the hull’s in the water to when it’s foiling. It was a matter of trial and error until we got it right.

“Every time we go out we learn something new;  the aero guys’ targets change and the trim changes.  It’s great to be able to try different settings – a new game for everybody so it’s quite exciting.

“Crew work will continue to keep getting better and better but I think that even if we sailed every day between now and the America’s Cup we still wouldn’t be totally satisfied.”



  1. Trust you guys will be more than confident enough to take back the cup…… keep up the excellent team work !!

    Marc Dupavillon - November 19, 2012 at 12:52 pm
  2. Thanks, Glen! I am really enjoying reading and watching the progress of this amazing boat. I now want a wing and foils for my boyer mkIV. Best of luck, Stuart

    Stuart Parker - November 19, 2012 at 2:39 pm
  3. Nice to hear from Glen Ashby: thanks for the entertainment..

    Indio - November 19, 2012 at 2:41 pm
  4. Good report. Thank you.

    Are you completely recovered from the mishap that knocked you out of the last AC45 festivities?

    All ok now?

    Roger Boshier - November 19, 2012 at 6:39 pm
  5. Most interesting and informative report. Please keep them coming.

    Marcel Fachler - November 20, 2012 at 4:40 am
  6. When you;ve got two wings you build a rather large glider.

    Great to read these short info bites from different parts of the team.
    Well done guys for playing the open book. It’s making fans all around the world.

    Keep of finding the gains. Cheers

    Paul M Smith – On the Mighty Kaipara - November 20, 2012 at 6:37 am
  7. THAnks heaps – it’s nice to have interest maintained in th eteam :-)

    Dave - November 21, 2012 at 2:30 pm
  8. Logging in most days now very interesting to here from different people in the whole group,
    Good luck.

    Kevin Oliver - November 22, 2012 at 8:32 pm
  9. Great article again. Thanks.
    Maybe some of you guys should take up Moth lessons. Same procedure. Lots of similarities. When up on foils, change your sail profile immediately, closed leech and all.

    Some do it better than others. The top guys are reaching now 17kn upwind which is a steady increase from 13.5kn over the years. I know you have the expertise.
    Smooth sailing!

    Manfred - November 23, 2012 at 12:25 am
  10. Great stuff guys. What you are doing is good for all sailing. Thanks

    Bob Dee - November 23, 2012 at 11:05 am
  11. Great update Glenn, thanks for another perspective. All the best for the rest of your trialing.


    Geoff - November 27, 2012 at 8:22 am

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