The skipper of a 56-foot voyaging canoe was unable to explain why his vessel sank Monday — with students aboard — in the Philippine Sea, 90 nautical miles northeast of Palau.

“We’re not really sure how it sank,” Sesario Sewralur, master navigator of the Alingano Maisu, said in an interview on the Oceania Television Network. “We just realized the back of the boat on the port side was so heavy. It was so quick to fill up. We tried to bail it out but could not. We gave life jackets to all the crew and students.”

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The Alingano Maisu was a traditional single-mast, double-hull Hawaiian voyaging canoe used in Palau Community College’s non-instrument navigating program.

It was carrying 10 crewmembers, including students from the community college. All were rescued. The crew used a satellite phone to tell the community college it was breaking apart and sinking, Sewralur said.

The U.S. Coast Guard contacted a nearby ship, the 960-foot Hyundai Unity, which diverted to recover the crew, who were returned to Palau 12 hours after the distress call.