For the families of the 10 sailors who went missing when the USS John S. McCain collided with a commercial vessel east of Singapore, the days after have been an agonising wait.

Megan Partlow, who lives in Ohio, said her fiance, 21-year-old Jacob Drake, was one of the sailors still missing and that there had been no news on his fate by Wednesday morning, more than two days after the collision. The two planned to marry next July. “He is honestly my perfect match,” she said.

Mr. Drake joined the Navy out of high school and loves it, Ms. Partlow said. “He likes helping and volunteering as much as possible. He also loves all the people on his ship. They are all like family to him.”

Search-and-rescue teams from five countries, including the U.S., nearly doubled the search area on Wednesday to more than 2,100 square miles.

“It’s quite clear that the U.S. Navy is running short on capacity, not just ships but of manpower,” said Collin Koh, research fellow at the Maritime Security Programme of the S. Rajaratnam School of International Studies in Singapore.

A Navy spokesman declined to comment on the causes of the crash and possible manpower constraints.