Please select your home edition
Edition
SOUTHERN-SPARS-AGLAIA-SPARS_728X90 TOP

America's Cup: Kiwi's AC40 nosedives causing structural failure

by Richard Gladwell/Sail-World.com/nz 20 Nov 2022 23:35 PST 21 November 2022
Emirates Team New Zealand AC 40 - November 21, 2022 © Adam Mustill / America's Cup

The issues of sailing foiling monohulls in top end conditions were underlined today, when Emirates Team New Zealand nosedived their AC40 during a training sail on the Hauraki Gulf and suffered substantial structural damage to its deck and bow sections.

The AC40 was towed home early afternoon, after exiting the inner Waitemata Harbour three hours earlier at around 1000hrs.

The breeze was blowing from a NW direction, which is an unusual direction but one which has been notable for several incidents with racing yachts, including the capsize of American Magic's Patriot on Day 3 of the 2021 Prada Cup.

It seems from a statement issued by the team that they had decided to test the AC40 in the knowledge that conditions were extreme in the area, off the northern side of Waiheke Island and approximately 16nm from Auckland.

Auckland has been subject to some severe weather over the past few days, including waterspouts, and severe rainsqualls in the Hauraki Gulf and Rangitoto Channel.

Today the conditions were relatively sheltered in the Rangitoto Channel with several cruising yachts sailing and looking comfortable in the conditions.

However in the area chosen by Team New Zealand for their testing, readings from Predictwind recording stations indicate that winds in the mid-20kts range were recorded around 1100hrs and again in the early afternoon. According to Predictwind, a 30kt+ rain squall was recorded in the area around 1100hrs just before/after the AC40 capsized.

A search of AC37 Recon Team images - using the metadata for each image shows that the AC40 was sailing at 1040hrs and was capsized three minutes later.

The rain squall mentioned in the graphic below, was recorded 4nm west, of downwind of the capsize location, at 1100hrs, but as can be seen the wind increased dramatically. The team later claimed that the windstrength was only 15-20kts at the time which is confirmed by the sea state in the images of the capsize.

The recovery operation was not easy, however Emirates Team New Zealand have previous experience in these situations, it is their fourth known capsize.

Once it was righted, the GPS track shows the AC40 was towed to Matiatia, a sheltered harbor at the western end of Waiheke Island, presumably to get the water ingress issue resolved, enabling the AC40 to be towed home on its foils.

The yacht towed past North head around 1324hrs this afternoon, heading for haul-out at the team base.

It is not immediately clear what the effect of the incident will be on Emirates Team New Zealand's development program. The AC40 will obviously have to be repaired, but that should be possible in New Zealand using the team's own construction facility and building team. Normally new sections would be laid up in the original tooling to get the external shape accurate, and bond these in place of the damaged sections. However the tooling is with builder McConaghy Boats in China.

The team had, today, posted a schedule of parts that were to be tested which included sails. Obviously these test plans will be delayed by the fallout from the nosedive. The team is taking delivery of a second AC40 in December, which will require strengthening in the bow area before it can be sailed by the team.

The damage is a separate issue to the tribulations of sailing foiling monohulls in a seaway.

Last week, swells of around 2 metres were reported at Barcelona, during a day in which it was too light for Alinghi Red Bull Racing to sail.

The Swiss team, sailing Emirates Team New Zealand's former AC75, Te Aihe, have nose dived spectacularly on other at least one other occasion in Barcelona, with the AC37 Recon Team images showing the AC75 with its rudder elevator clear of the water. There was sufficient force generated by the nosedive to blow the clew out of the AC75's jib - making a spectacular image.

No crew have been injured in either incident.

A statement issued Monday evening by the team reads:

Emirates Team New Zealand have suffered damage to the bow of their AC40 today after an early start testing on Auckland’s Hauraki Gulf in some top end conditions.

In recent weeks the Emirates Team New Zealand AC40 has been taken out of its one design configuration and testing stepped up in its development and data collection towards the design of its AC75.

The team were testing under manual flight control to the north of Waiheke Island in around 15-20 knots of windspeed and large waves. While sailing downwind at over 40 knots of boat speed, the crew onboard lost control of the ride height which caused the rudder and elevator to come out of the water. This resulted in a high-speed uncontrolled gybe and simultaneous deep nosedive followed by a capsize.

The resulting impact of the water pressure collapsed the foredeck at the bow of the AC40. Significantly the watertight bulkhead aft of where the damage occurred maintained its structural integrity, successfully serving the purpose of controlling water ingress so the boat could be righted and towed back to base.

Within moments of the incident, the team on the water and design and build team back at the base were well into a program to assess the damage and repair timeline but also importantly understand the precise loads on the structures in the incident and lessons that can be learned and implemented going forward.

Emirates Team New Zealand CEO Grant Dalton said, “It appears that when the boat nose-dived, which was the best we have done, the high water pressure and side load collapsed the forward section of the deck causing the resulting bow damage. The designers are analysing the load cases of the incident and although it might be too soon to tell, it is likely that we will have some retrofit structure necessary to our boat and throughout the AC40’s fleet. But we will understand this further in the coming days.

The AC40 was towed back to base on its foils after the incident and is back in the shed being assessed for the repair job ahead.

Related Articles

America's Cup: Arb Panel dismisses US request
The America's Cup Arbitration Panel dismisses American Magic's application to skip Jeddah regatta. The three man Arbitration Panel has dismissed the Application by the New York Yacht Club's team American Magic to be excused from participation in the second Preliminary Event, part of the 37th America's Cup. Posted today at 12:24 pm
America's Cup: Estrella Damm returns for third Cup
As the official sponsor, Estrella Damm will be the competition beer The Antigua Fábrica Estrella Damm in Barcelona has hosted the presentation of Estrella Damm's sponsorship of the 37th America's Cup, which will be held in Barcelona in 2024. Posted on 29 May
Cup Spy - May 27: Emotional reunion for Italians
Emotional reunion at sea with the Amerigo Vespecci, sail training ship of the Italian navy. The Italian team planned an emotional reunion at sea with the Amerigo Vespecci, sail training ship of the Italian navy Emirates Team New Zealand did some damage believed to be electronic related, and their session stopped early. Posted on 28 May
Cup Spy May 25-26: Solid day for Med based teams
The British and Italian teams both had solid training days on the Med. The Swiss had an AC75 day. After losing a day to no wind, the Kiwi two-boat testing started on Thursday. The British and Italian teams also got solid training days on the Med, with both doing speed and match race testing. The Swiss sailed their AC75, including a photoshoot for F1. Posted on 28 May
America's Cup: Predictwind sets up in Barcelona
Predictwind will be establishing the Common Weather Program for Barcelona. It is live now.. The Challenger of Record and Defender (COR/D) have announced that Predictwind, the world's leading marine forecast organisation aimed at sailors at all levels, will be establishing the Common Weather Program for Barcelona. Posted on 28 May
Cup Spy -Special: Kiwis start Match Racing
Emirates Team New Zealand have just wrapped up a match race practice session off Takapuna Beach. Emirates Team New Zealand completed a match race practice session off Takapuna Beach, on Friday. Here's Cup Spy's take having watched most of the session shore-side on the Takapuna Beach seawall - via a pair of Fujinon 14x40 gyroscopic binoculars. Posted on 27 May
Cup Spy - May 24: Robertson joins the Swiss?
The Swiss christen their second AC40, watched by top match racer Phil Robertson. What is his future? Four teams sailed on Wednesday, May 24 from Auckland, Mallorca, and Cagliari. Alinghi Red Bull Racing christened their new AC40-7, and took it for a tow-test off Barcelona. Top Match Racer and SailGP helm, Phil Robertson (NZL) was again present. Posted on 26 May
Cup Spy - May 23: Kiwis hit 50.7kts
Emirates Team NZ was out of the shed before 0630hrs, and set a new speed record of 50.7kts Emirates Team New Zealand had an early start, with a poor forecast which didn't eventuate. The Kiwis set a new top speed of 50.7kts - achieved in a bear-away. Alinghi Red Bull Racing broached twice in top end conditions - self recovering each time. Posted on 24 May
Cup Spy - May 22: Brits at pace, as Italians race.
The AC37 Joint Recon team following the Brits reported them hitting 45kts downwind. Two teams sailed today - Luna Rossa from Cagliari, doing some race practice using a team chase boat as their opponent. INEOS Britannia sailed from Palma, Mallorca. The AC37 Joint Recon team following the Brits reported them hitting 45kts downwind. Posted on 23 May
America's Cup: Join ETNZ for a dual AC40 training
Join Emirates Team New Zealand on their Chase Boat for a session with their two AC40s Join America's Cup Defender, Emirates Team New Zealand on their Chase Boat as they move away from the AC75 test program and onto two-boat testing with the two AC40's. Posted on 22 May
Hella Dual Colour Floodlights - 728 x 90px - 1 jpg BottomJ Composites 2022 - J45 v4 FOOTERSailGP_Technologies_Caro52_1456x180 BOTTOM