Alinghi – SUI100
Luna Rossa Hull – very slab sided
Emirates Team New Zealand – NZL92
This entry was posted on Tuesday, April 3rd, 2007 at 11:54 am and is filed under Alinghi, America's Cup Teams, Americas Cup, Emirates Team New Zealand, Sailing, Sports, Valencia, Yachting. You can follow any responses to this entry through the RSS 2.0 feed.
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Hope you’re having fun, I’m getting pretty excited now. Interesting looking pics of keel bulbs, i’ve heard that the Luna Rossa hull shape is a bit out there, but I havent seen any pictures of the underside other than the one posted here.
Say hi to Martin
If you’re looking for the italian boats and other bulbs on the italian newspaper online you can found some… I’ve republishied from it some pics on our Blog…
Obviously we fight for Luna Rossa .. .. and other italian ships: +39, Mascalzone Latino and for Shosholoza.
But NZL is very expert and exciting the passion of that people for sailing..
So let’s look a good match racing…
[...] boat still looks to have the same bulb – the shorter one with the Kiwi flag on it. They may have a new rig in the boat, but it is still one that has four spreaders. A new rig may be [...]
Is it possible that SUI100 attaches the mast halyards to the keel below the water line (i.e underneath the hull)? This would comply with the definition of a “fixed” keel but allow leverage from the mast to stabilize (or even twist) the keel in a lateral direction to oppose the natural leeward sag of the keel during tacking. It would also comply with rule 17 and its interpretations as the effect would be passive and could be interpreted as a secondary support for the keel. What rule says that the mast halyards can only attach to the keel at its head inside the boat? The bulge on the SUI100 keel would be a seal to prevent water entry into the hull where the halyards penetrate (the seal would be fixed – not flexible). If this is the approach the Swiss have taken, then the Kiwi boat may be at a deep disadvantage.
G’day Alan. Very interesting. Surely the measurers’ test is whether they’d be halyards in the true sense (to raise and lower sails) or a thinly disguised adjustable guy wire system.
But then does the ACC Rule exclude such a guy wire system – probably not, because nobody has thought about it before Alinghi. Don’t you just love the AC? Just one question. How much deflection would there be in a fixed keel on a current generation Cup boat? Cheers, David G.
According to the final set of interpretations, forces on the rig can’t be used to deflect the keel, so if they did try that it’d be pretty subtle and would hardly classify as a silver bullet. One suggestion I quite liked was that there could be a sort of “anti roll bar” (like the things used to stop cars rolling) enclosed in the hull which would put pressure in the opposite direction to hydrodynamic forces, but even that is unlikely.
Just as with the Hula, attempts to squeeze one past the rulebook tend to fall flat. To make sure they aren’t illegal the concept has to be watered down to the point where there is little advantage in doing it, and the amount of time and resources taken to design it and make sure it’s rule compliant could be better used elsewhere. This is why the two Blake/Coutts campains worked so well – they didn’t try to find a miracle sure like we did in 86/88/92/03, instead focusing on using the limited time and resources as efficiently as possible. If we beat Alinghi this time I’ll take it as the final proof that that is the right way to do things. We’ll find out in a week and a half.
G’day Carl. Interesting. Brad Butterworth is on record as saying Alinghi has concentrated on testing rather than racing – maybe much like our ill-fated TNZ Defence of 2003.
There may well be fresh fruit on SUI100, but as you say, by the time it is watered down to comply with the Rule, will it be enough to give Alinghi a speed edge. Unless it is of course a legitimate breakthrough like AustraliaII’s winged keel. Speaking of which, isn’t it interesting to see how far the thinking on winged keels has come since then.
Since you have an interest in “things under the water”, here’s a question which puzzles me about conventional Canting Keels (as in Volvo ocean racers). I understand how the righting moment is dramatically increased when the keel is fully canted (acting like a fulcrum in effect) but how does this affect a yacht’s ability to track and point? My thinking is that the foil, being shallower in the water, may not give as much lift to windward. And if this is the case, I can see a blistering speed increase on a reach, but what about going stright up hill? Your thoughts/ Talk soon. Regards, David G.
Good point David G. The Volvo racers don’t point that well up wind, and usually stay on one tack for a long time. If Acheathi have a way of deflecting their kee,l the rules won’t alow them to lock that deflection in place. I have a theory on how they might do it. If they built the hull with a relatively flexible mid section with the keel firmly bolted in place, they may be able to use side stay tension to twist the hull to windward a little bit, which would in efect rotate the midsection in relation to the bow and stern. It wouldn’t have to be much, but it only takes a few degrees keel movement to get an advantage, and it would probably beat the rules because they don’t measure the boat under load. I taped some footage off the tv of alinghi sailing up wind on starboard tack, and the topsides of the hull near the chain plate and forward to the bow certainly look a little strange.
Interesting observation, Daniel. Rotating the hull rather than the appendages wouldn’t interfere with any rules as far as I’m aware (if only because the rule makers would never have thought of someone doing that). I do wonder how that’d effect the hydrodynamic behaviour of the boat (waterline length, wetted surface, etc). It could explain why NZL92 and SUI100 look so different.
The reason canting keels were outlawed (or at least supposedly) is because they do no favours to matchracing. The goal is to make it less about having a procession of fast boats and more about tactics, picking the wind, ability to point the boat and sailing ability.
David, my understanding is that conventional canting keels can be put in a ‘neutral’ position during tacking duels and so forth. Optimum use of a canter would, as you said, be in a long reach. Of course, any form a canter took in an IACC boat would be far from conventional so it’s hard to comment about how it would work in that context. Given that NZL92 is designed to heel very quickly being narrow as it is then things may get interesting if a tacking duel develops. If Ed Baird keeps a looser cover on ETNZ in the race than you’d expect then it’d be a hint that this might be the case.
Holly crap. Daniel. You should be in the ETNZ design team. There no way I’d have thought of rotating the hull Vs canting the keel. But of course the end result would be pretty much the same. Reminds me a bit of my old P Class days – the flatter you sailed her the faster she went, depending on the breeze of course.
I guess it’s that age-old story. We just have to ask ourselves, “Why do we do it like this? Is there a better way?” If your answer is, “Because we always have”, then it’s time to get out of the AC business. Cheers, David G.
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