Kiwi's hula gap

I agree with Cougar. The Kiwis had a potential winner. But they forgot the sloshing effect. The sailtrunks must be made of anti-sloshing material. Similar that used in cars. Thus, absorbing and keeping the good water at the stern. Keeping the overhang effectively down. Moreover, some of the bolts fastening the hula must be loose. Thus, letting water come into the hull. The amount of water coming in is calibrated by the gap between the hula and the hull (and hull speed). The basic problem for the Kiwis in the first race against Alinghi was bad calibration of the hula concept. The large fleet of spectator boats at the starting area altered the water properties. (A related problem arised in San Diego when the choppy sea harmed the single-fin Farr Kiwi.) In Auckland the substantially increased petroleum and Diesel emissions reduced the water viscousity. Thus, the hula-gap swallowed to much water, and the rest is history. Again, one has to take into account the spectator-fleet influence at the start. I am a little bit dissapointed about Clay Oliver’s doings here. I had pointed out this problem to him half a year earlier.


Interesting. A few questions:

What do you mean by sailtrunks? The stern scoop area where the water was a-sloshing?

Bolts? You think there was a leak in the hula-hull layer?

Not sure I buy into the viscosity idea. The amount of petroleum needed to change the viscosity of the Hauraki Gulf would be…well… a lot I think. The hula gap, to this layman, has a static volume (the IACC rule insists that the appendage not move), so how it could be filled with more water than they planned would be a mystery to me.

I’m not an engineer, though, so maybe I am off in left field? Booster - don’t take my questions as an attack (disclaimer needed for this site), I am just “into” the AC and love discussing this stuff.

The Other Matt

As I recall, the problem in race 1 was taking in water over the side, not through the Hula. That is why they added that cockpit skirt for subsequent races.

The Hula was designed to increase the effective waterline length without being measured waterline length (thus allowing the boat to skirt the rules [pun intended]). They had done enough CFD work to know the downside of extra wetted surface area. You may be right that as the stern of the boat rises and falls in the waves, that the water between the Hula and the Hull may have gotten sloshed and pumped in and out. And perhaps the excessive waves in race 1 made the problem worse, but I’m not sure there was a way to stop it. Remember that the ACC rule specifies that the appendage can only contact the hull in the 500mm wide region along the centerline, so they could not have used any sort of gasket to seal the hula Gap as that would have constituted “touching”.

I’m just glad the Hula concept failed or all the boats would be sporting strap-ons for the 2007 cup. That would have been a big step backwards…

  • Will

Will Gorgen

We are safe for 2007, as they are now illegal. No big loss, obviously!

The Other Matt

The story I heard from around the waterfront was the original gap was very small, but as the Cup was getting closer the measurers started to feel uncomfortable with it, and asked for it to be increased. I believed it was altered several times, so the measurers where convinced it would not touch the hull. Thus decreasing the efficiency of the hula.

This is my theory (correct wording for the moderators) that the increased in water volume (weight) between the hula and the hull didnot allow the stern of the boat to lift fast enough in the extra slop and wakes allowing the water to came over the gunwales.

As for the water, does it aways flow to the lowest spot!!!

It’s the PUB can I say this here?

Seems like an excellent example of how an idea, no mater how well intentioned on paper or in the computer - didn’t prove out too well in actual competition!

Just doesn’t seem like NZ put a lot of effort into “on-water” development and testing. The concept of the main boom made sense, just wasn’t tested well enough before being pressed into service. Will be interesting to see what the next “hot” idea will be for the next race.

The Hula was based on the same theory as the double knuckle bow, which worked out really well. The bow idea was somewhat of a rule beater, but for me it falls into the clever category. The Hula was a downright cheat in my opinion.

TNZ had such a long history of innovations that I think they fooled themselves into thinking all their ideas were good. The fact that so many of their idea went bad in one regatta is ironic, I guess. Either that or it shows what happens when you do not approach a design effort with adequate enough skepticism…

  • Will

Will Gorgen

I completely agree Will.
Another interesting thing here is that the Kiwis did what some here in the states wanted to do, and that was to concentrate all the AC effort into one team. Some here in the states felt that having several syndicates to go over for the cup was wasting talent and technology. I think the Kiwis showed this thinking to be very wrong for the fact that they had no other defense teams to compete with just killed any chances of them defending the cup successfully. I think we all know now that just about any team could have had a chance to take the cup from them.

Good point Greg - amazing how fast I am sailing - when there is no other boat !

I think the hula was a good idea on paper, but i to think maybe the should have built like a 30 or 40 foot boat and taken it out sailing to see if it really worked. Reminds me of something they drove into us at college, “theory is great but it better be practical”


Hey Greg,
Remember NZL doesnt even have a population of 4 million people…I am not sure NZL could support 2 cup teams.
If Coutts and co had stayed in NZL I think we would still have the cup.
I think the design team was given full license to go after everything as the sailing team was somewhat depleted and inexperienced in AC cup terms.I think we would have seen the same result if both teams were sailing the same boat.
my 2 cents

you may be right withthe idea of coutt and butterworth staying in nzl. but the end of it was that the testing on the boat just was not there. i would have love to see a good set of races. i live for the americas cup . but the end of the story for me anyway , was after race 1 , apart from the hula. was the fact that the races between oracle and alinghi where better. depending on conditions , it was the sailor who provided the results. and in the final. all we could talk about was the complete failure on nzl 82. we all talk about the water. but for me, the ultimate “wrong” here was , “A FINGER TIP BOOM”. I dont know about anybody here. but i would assume new zealand tested it, and thought the had something, and when it broke, that was the start of the boat . stoping in my world
btw i l;ike the tone here


Absolutely I agree that the team of Coutts and Butterworth seem to have proven that they also could have won in most any boat out there. Coutts is just an amazing skipper, and Butterworth really seems to click with him.
Now the part about NZ not being able to afford more then one syndicate…I don’t think I believe that. They did it back in the plastic fantastic days, though the $$ was quite a bit less. And let’s not forget that monster that came over here to challenge the cup. There is money there.
But you are certainly closer to it. What kind of challenges will be coming out of NZ for '07? More then one syndicate?

I agree with Brett that Alinghi had the better team. I don’t think RC and BB could have won with NZL-82, though. I’d don’t know if I’d go so far as to say 82 was a good idea on paper, maybe just “an interesting idea”.

Teams - yeah - no way New Zealand could have supported two teams. There were a lot of questions coming out of 2003 as to whether they could come to play in 2007. Brett, what is the latest on the hoped-for BIG sponsor that Dalton thought we’d know about by the end of January?

USA, Greg it looks like we may finally have our efforts behind one team, as it is unclear what TDC and OneWorld will do for 2007. Oracle has so much momentum going now, that it would be tough to compete against them (for any challenger!).

In other interesting cup news…I see Alinghi has hired ex-Illbruck designer Michael Richelsen (ex-AmericaOne as well).

Of course, you keep up with it all here (shameless plug yet again):

America’s Cup News and Information from

The Other Matt

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by Matt White

I agree with Brett that Alinghi had the better team. I don’t think RC and BB could have won with NZL-82, though.
<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
Don’t know if I made it clear, but I do very much agree with this Matt.

I’ll check out the AC web site there. Just as long as the name Ken Read is not there, I’ll be happy! DC’s biggest mistake!

I think it’s safe, Greg, we seem to be “Ken Read free” at this time. I too was dissapointed in Read, and TDC, as they were “my team” going into 2003. Would have been interesting to see how they would have performed if they had not scuttled 77.

The Other Matt

I think the working theory on the finger boom failure is that as NZL82 took on water, the loads on the sails increased above anything they had tested until it finally broke the boom. The boom failure was a secondary failure caused by taking on all that water which made the boat several tons heavier than it should have been.

My “guy” has always been Peter Holmberg. I was down in the BVI in 1998 when his Virgin Island team was still alive. I had a chance to meet him and was very impressed. I’ve met DC a few times and thought he was an over-rated a-hole. Never liked Chris Dicksons style either.

The only other cup helmsman that I have met is John Bertrand. I actually had a chance to sail with him a couple of times and he is great. If he came back into a cup team, I would cheer for him hands down…

  • Will

Will Gorgen

Anybody else think that just maybe the opening post here is a bit of a joke? The stuff about the “bolts” having to be loose to let water “into” the hull might be a tip off…

I think so too, but I might be wrong [:D]

if it isn’t broken, don’t fix it!

I said if both teams where sailing the same boat…not if they swapped boats.