Luna Rossa exposes Team New Zealand's costly design choice

Emirates Team New Zealand's Achilles heel was exposed Yesterday by lunar Rossa and it might have gone unnotice just how significant Emirates Team New Zealand's pre-art issues were but when we break down this botch tack step by step I'll then link it to the design choices that Emirates Team New Zealand have made and I'll explain to you why this is a vulnerability that lunar Rossa or any of the other Challengers may look to exploore through the round robin and in the Cup match itself let's first of all take a look at the incident yester I'm talking about which largely decided the race and gave lunar Rossa their lead this is approaching the start you can see 26 seconds to go the starboard end of the line is just up um here just off screen Port end way off here and the wind is clocked round right meaning they are way over the starboard lay both of them looking to duck down to get to this line and I already know things are a miss here just judging by the turnup number 17 cup challenges so this is a Roundup you can see lunar Rosa are affecting this turn up into wind and they're not having to pull the main all the way over to make this round up whereas Team New Zealand having to pull their main all the way up on the track traveler to wiw to try and head up and you can see there's a large um ventilation of the rder in doing so quite a twisty main so that was the first indication to me that something potentially wasn't quite right here he skipping forward to the actual start lunar Rossa get this powerful um kind of reach over the top of Team New Zealand Team New Zealand look pretty defenseless this is just an incredible pre-art um Luna Rossa hit I think briefly 48 knots in the prart reaching down the line just incredible to get the jump on Team New Zealand the course is Right favored is Right skewed so and predicted to keep on clocking right as well so getting access to the right hand side of the course early looks good so Emirates aren out of this even though they're going 10 knots slower if they can perform the Roundup get into an early tack then they are good but then this happens race 17 in so just pause that the start's gone lunar Ross have hit the start online you can see lunar Rossa in just off the bow of emeres Team New Zealand emeres Team New Zealand are trying to head up here and I know they're trying to head up even though the boat's not turning because their main sheet is all the way over to Winwood and that is something you would naturally do when you want to head the boat up into the wind you'll pull on the main sheet which drags the stern of the boat um through the wind or drags the nose up into the Wind by changing the balance between the jib and the main but for some reason the boat doesn't turn just keeps on going straight they eventually drop the windward um foil um and eventually start to turn they're having to use so much M she all the way up traveler all the way up to Winward see they've dropped down to 20 knots 18 knots 16 15 14 and they are now off the foil even in this Frame so um a few seconds before the start you can see um just here that team E's Travelers already quite a long way and they've got huge amounts of twist on their main cell whereas their jib is relatively tight um on lunar Ross you can see the main sell is really far up but the jib is quite Twisted you can see the bottom half of the jib but the top half is so Twisted it's effectively invisible to us there you can see it just coming into frame so you can see how much twist they've got on the jib the main sheet is on a bit got a decent amount of twist whereas em Team New Zealand have their travel up to the Winward side of the boat but their jib is quite tight already strapped down quite tight this tells me they are or just the amount of travel they've got up tells me they're already trying to round this boat up into wind and struggling before they go through the wake of um lunar Rosa now you can see lunar Rosa do actually um lose their rder slightly as well in this head up with this plume of white but the boat does still head up and that's for two reasons they basically got the boat in Balance through the trimming of their sails their main is quite Twisted but not hugely The Traveler up on the Midway but this jib is really eased out loads of twist on it loads of belly coming out at the top whereas on Team New Zealand boat who are trying to round up as well their traveler is now all the way up to the windward side but huge amounts of twist on their main sail I'd say the top of their sail is eased further out than lunar Rosa but the bottom of their sail is up probably 10° from where lunar Rosa is to start their problem so they're trying to turn the boat but the boat won't turn cuz the jibs on and the Main's got no leech tension to swing the back of the boat through and twist it up into the Wind by changing the balance between the jib and the man the Windwood board goes down and the boat is just at this point it's not turning into the wind it's just slipping sideways loads of side slip here and the main sheet is all the way up you can just see the top of this s is completely ineffective no leech tension at all whereas lunar Rossa have only got their main on the center line but decent decent leech tension you know it was quite windy so still seeing a decent amount of twist but they do have some leech tension um and their ruers regain flow from about here and for a good few lengths whereas Emirates Team New Zealand despite having two falls in the water they're still effectively slipping sideways and they kind of skied into this tack um drop off the foils we know the crooks of what happened they slipped sideways and um fell off their fors in the attack but what about the team New Zealand design has led to this situation what are the choices they made which have led to this vulnerability so I'm just sharing with you a data visualization from ER DB and for me the really interesting graph on the right hand side is this bottom one which is your so that's how the boats are either crabbing to Windwood with um negative leeway or falling off to leard which is leeway that you know kind of all Sailors know and actually most boats sell typically with about three four maybe five degrees of leeway slipping sideways these boats typically sell with almost no leeway or or negative leeway actually crab to Windward on their canting foils Team New Zealand hit almost 30 degrees of leeway going into this tack typically looking at other tacks they're about 15° so double the amount of leeway and I think it's the leeway which really causes the rudder to stall in that the main forward isn't quite gripping enough the sail balance is out of kilter as well which is killing it they've not got enough leech tension on the main cell they've got too much leech tension on the jib and all of that contributes to that boat just not wanting to round up into the wind that is a big problem for doing Maneuvers pre-art like the what is it about the team New Zealand design decisions which has led to this now I think it's something we spoke to about on the Mozzy sales channel before and it's the way they're controlling their main systems so for those of you who don't know I'll bring the pictures up on screen Team New Zealand have a complex main sheet system where they basically have a separate main sheet for either skin this is something no of a team well no of a team has except or an Express who bought their design package but effectiv you have two main sheets one for the starboard side one for the port side all the other teams have one one main sheet which then goes up to a link attaching to the two skins and the link is passive allowing the two skins to slide over each of in attack now the pros of this system I think we're seeing in some of Mt New Zealand's ability to do low speed tacks with good gliding into the eye of the wind because they can really control those two skins independently flatten them off really control the moment that the battern pop through with the master with the link controls that can be done with a lot of presets quite clever the downside to this system and I mentioned it in my video reviewing this when we first saw it is do they have the power to actively control this yes having two skins two main sheets means the load will be effectively hared because you've got two of them but you've then got all the extra friction of moving through two purchase systems and you don't have the massive system sliders linkages which of the teams have which don't need any energy to coordinate whereas this is really energy intensive so I thought this could always be a Achilles heel of emerit to New Zealand would they be able to provide the oil to this system to really adjust the main sheet tension rapidly and looking at how Team New Zealand approached that start line with so much twist very little main sale on and lots of shib to kind of balance the boat in the heel Direction they just weren't in a position to sort their saes out to actually round their boat up into the wind and I think oil and power really could have been an issue because we hear from um Jimmy in his interview with um Planet sale I basically emptied the accumulator beforehand with a a couple of other moves kiwis ended up in your dirt I mean turbance in the water spun out as a result was that was that part of the game plan from you or cuz we hear about spilling dirty air over people but not so much wash yeah I haven't been out to really review the footage that much um so I really don't know I mean it could have been a lack of oil for them um I'm I'm not sure turbulence I don't know how it played out but so Jimmy gives great interviews and this is from Mattan at Planet sales so thanks to Matt for getting this interview and you know Matt suggest whether the skid out was because of the turbulence in the water for lunar Rossa possibly but I'm actually with Jimmy here and that I think it was an oil issue that teamand just aren't able to get the amount of oil to this twin skin system to do though to get the main winched on from doing these big bear ways in lots of Breeze where you need a really twisty cell to then heading up onto the breeze to get that main cell clamped back down and lunar Rosa and all the other challenges will take a great amount of Confidence from this so just looking in more detail about probably one other feature as well which may be exacerbating the situation for Emirates Team New Zealand run after of the team New Zealand boat is pretty straight to here and then it comes up gently to the rer at the back good look at it so you can see how this straight this bustle tapers a long way after means that it can dig in the water and stop the boat from from um from turning as well um you can see here that that this kind of vertical Edge sits down in the water on the water line whereas when we look at lunar Rosser their belly tapers up and it does mean they've had to put more workings the riter above deck cuz they brought this up so they've got less space for Ridder workings in the Box here it does mean when we look at the boat floating on its waterline if I zoom in that actually this kind of straight edges these parallel edges do sit above the waterline so they're less likely to dig in and attack um whereas Team new zealands definitely dig in during attack and would make it even harder to round that boat up into the wind so for me there are two key design elements from Team New Zealand which are are positive in a way hiding that R workings in the box is more Arrow having the end plate run further ass a and be lower down again lets less air underneath the boat so is good when flying but causes them issues to turn the boat secondly their main sheet setup which I think they're doing quite clever things with during tax is excellent and gives them more control over the main skins but it's more oil hungry and potentially they've come un stuck against a simpler lunar Rossa setup in the pre-art as always let me know if you think I'm on the money with this theory if you think it's interesting share it to your mate get involved in the comments below thanks for your time see you around