Jul 12, 2016

Groupama Team France AC45 Turbo launched


Photos: Team Groupama France vid grab / groupamateamfrance.americascup.com/ Video embedded below. --
How can you transform such a beauty and weapon looks of the AC45 floating version and the ones made by Artemis or BAR into this ??

Remember I only dare to criticize high profile projects like the AC for ie.  If I don´t like a beachcat project I just try to keep my mouth shut as the funding, investments & man labor efforts are far too distant from these Multimillion dollar boats.

Lets try to dissect this extreme custom hull modification of Groupama Team France AC45 Turbo:

- Modified forward / bow rocker section, they gave a more steep/pronounced curved from orig lines. This has been implemented in several racing beachcats like Manu Boulogne Cirrus R or even Melvin´s Nacra 17.
A more rounded rocker provides better tacking (quite noticeable on the Nacra 17s) and also reduced drag in floating mode as literally the bow bottom section is not generating friction with water surface.

- Bow rails: Original intention for the Wildcat was NOT an anti pitching feature as we explained many times and also confirmed by Martin Fischer himself. Main purpose of the bow rails is to reduce drag preventing water to cover bow's deck area. It also gives you structural benefits on the nerve created by the step. So its strange to have this on a full foiling hull.

- Forward deck / volume: They literally cut the original AC45 bottom hull lines to feature the above mentioned bow rocker they needed to compensate the actual removed volume, thus the designers (Fischer is head Design and Juan K are part of the team) modified original 45 deck lines adding a 'bump' in order to compensate the lost volume.

I had this in mind when drawing the F18 OP / Exploder lines, so I decided not to go for an extreme
concave bow rocker to maintain smooth deck lines integrated with volume. (This AC45 and the Cirrus R have an elevated deck) The F18 OP  still has more pronounced bow rocker than other F18s, and similar to the Nacra 17.

The other aspect I'm seeing is in contrast to the Wildcat bow is that  rails / steps are created simply by adding a wider crossection upwards the cut line. On the Wildcat you can see that the step / rail is created by a recess on the original  designed bow crossection so there is no added volume on the deck for the Wildcat.
Team France Turbo bow seems to have an expanded or bigger deck sectional cut which adds extra volume.

We've been preaching about pitching and volume in this web for 8 years now, but also remarked that the AC45s showed great margin in the breeze and harsh conditions. Once airborne volume becomes less important but you cannot get rid of it as seen here with the Flying Phantoms and Nacra F20s, which are capable to sail in the same tough conditions as their floating versions as they share same hull mold.

Also remember TNZ 40knots pitch at San Francisco, which was only saved by hull volume. Nevertheless I really don´t like at all what they have done here.
Artemis & BAR Turbos look well compensated and super smooth.

All in all seeing second shot above, the design team took special care of bow overall shape & volume, rare these days for foiling cats.

- Spoiler: This is the first time I've seen an asymmetric aero spoiler. Compare to the ones used or the AC72s.

- Transom : Didn´t find pics yet of the transom but it looks a rather sharp one, More when visible in coming shots.

- Forward beam position: Quite forward beam position compared to Artemis AC45 turbo, but the wing step is backwards from beam hull attachment and placed on the central pod structure as seen in this twitter pic by Philippe Elies and pic above.

- Foils: It seems to feature rather standard TNZ J and T rudders.

In the end the most important aspect are foils, and boat speed so beyond not being a stealth looking 45 like BAR's one the French Team biggest asset is their sailors & crew , who in a restricted design scenario given for Bermuda might well be the real performance difference this time around.

Beyond Cammas and other sailors, two F18 World Champs are part of the Team and feature in video below: Arnaud Jarlegan (2010 Erquy) & Matthieu Vandame (2012 LA).


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