SoftBank Team Japan’s preparations for the 35th America’s Cup suffered a setback after the team’s AC45S test boat was significantly damaged during a training exercise in the Great Sound last week.

The challenger’s wing-sail foiling catamaran experienced a daggerboard system malfunction which led to structural damage to one of the boat’s twin hulls.

The windward daggerboard on Team Japan’s AC45S exited straight out of the bottom of the boat during a gybe and struck the outside of the hull, leaving two nasty gashes, which has kept the team’s boatbuilders busy over the past several days repairing the damage.

“We entered a gybe as per normal and as we dropped the board we had a failure in the mechanical board system. There was an enormous noise,” Chris Draper, the Team Japan tactician and sailing director, said.

“I was to leeward already to drive out the gybe and at first I thought we’d hit a channel marker or something. We rounded up immediately and stopped the boat and found that the windward daggerboard had passed the top bearing meaning it had exited straight out of the bottom of the boat. The noise we had heard was the board hitting the hull from the outside. The whole thing happened very quickly.

“The hull had some damage to the core, which has been replaced and re-laminated. There is a bit of work inside the daggerboard housing itself and some work to do to the appendage.”

Dean Barker, the Team Japan CEO and skipper, added: “You have good days and then some not so good. A gentle reminder of the respect you need for these amazing boats.”

Fortunately, no one was injured during the incident.

The team was able to pinpoint exactly what went wrong through available data and on-board camera footage and expect to resume training in their AC45S this weekend.

“We are super lucky to have such a great boatbuilding team that have jumped on top of all of this along with great support from core builders and our cousins [Oracle Team USA] next door,” Draper said.

Team Japan’s mishap is the second involving an AC45 in the Great Sound in four months.

Fellow challenger Artemis Racing’s AC45F suffered extensive damage in a collision with the umpire boat during the past October’s Louis Vuitton America’s Cup World Series.

Umpires Peter Shrubb, the former Royal Bermuda Yacht Club commodore, and Alfredo Ricci both escaped with minor injuries while none of the Artemis crew were hurt.

Despite losing their bowsprit and genneker, Artemis went on to win the regatta.