US Olympian Bora Gulari lost parts of three fingers on his right hand when his catamaran capsized during training for the world sailing championships.
US Sailing said Gulari's fingers became entangled in the rigging of his Nacra 17 when it capsized in strong winds on Wednesday. Crew member Helena Scutt was not injured in the accident.
Earlier this month, Nacras that had been converted to foiling catamarans were recalled due to a problem with the daggerboards.
It is not clear whether that was the problem in Gulari's capsize.
Italian coach Gabriele Bruni came to the US crew's rescue, with US coach David Howlett arriving a few minutes later.
Scutt, who is also a US Olympian, sailed the boat back to shore with help from Rio 2016 Olympic gold medallist Santiago Lange of Argentina.
Gulari was recovering at a hospital after surgery and is expected to be back sailing in a month.