A bevy of Bermuda bubbles may have caused Emirates Team New Zealand to capsize in race four of their Louis Vuitton America's Cup challenger play-off semifinal against the Ben Ainslie Racing syndicate.
Alan Block, a correspondent for sailinganarchy.com, told Radio Sport's D'Arcy Waldegrave that the trouble occurred when Ainslie's boat bore off and left a "powerboat wake" at the race start.
"[That] wake of bubbles was full of air and not dense," Block said. "That's not normally an issue, but because [ETNZ helmsman] Peter Burling was right behind Ainslie, there was nothing to grip onto and the whole boat sank up to the mast."
Ainslie described the conditions, where the boats raced in around 24 knots of wind, as "like skiing on ice".
No one in the ETNZ crew was injured in the incident, barring a few bumps and bruises.
"I've been watching these [foiling boats] for years and they're normally more stable than that," Block said.
"Ben got Burling stuck in a bad spot where he had to bear away from slow to fast - a dangerous manoeuvre which puts the bow down.
"Burling had already dialed a bunch of extra lift into the foil, and when the boat picked up speed it was high on an edge where the water is thin. Then the rudder, which normally pulls down, came out of the water to further destabilise the boat."
America's Cup expert Peter Lester argued the conditions were unsafe for racing. He said questions needed to be asked of race director Iain Murray for allowing the racing to go ahead.
"In my mind [the wind speed] was above the upper limit," Lester said. "The rules say they can race up to 24 knots and that's a sample average of wind, taken from eight minutes to three minutes before the start.
"Clearly, today, the safety of the crew was compromised... the regatta has got off lightly."
Block disagreed, saying ETNZ "copped a bad one" but the regatta was about attrition and who was capable of recovering best.
"[Peter's] trying a bit hard. You can sail your Laser all day in 24 knots. I think it paints the wrong picture to keep these boats on the dock in what is barely a stiff breeze.
"If it was safe it would not be the pinnacle of a sport that's extreme at times, like Formula One or surfing.
"That's why only a few people in the world can do it. We should be asking these guys to push themselves to sail in breezes in which we'd sail our regular old boats."
Block was confident ETNZ could fix the boat and continue in the regatta.
"The wing [sail] is not an issue because they've had the other one fixed. There's not much structural damage from what I could tell. A big question is over the electronics, because the portside hull was submerged for a while. I hope they have spares.
"[ETNZ] contains the types of guys that get together and get it done. They are a confident team who will get back on water and handle Ben Ainslie fairly easily, provided there's not another mess.
"A bigger question is: Can Pete Burling recover? It was his error, no one else is responsible."