NAPLES, Italy — Much of the blow from Russia’s 2014 invasion of Crimea fell on Ukraine’s navy, which lost two-thirds of its men, the majority of its ships and its Black Sea port in Sevastopol.

The damage remains evident more than a year and a half later, according to U.S. Navy Vice Admiral James Foggo III.

“These are some heart-wrenching stories that this navy and these families have had to work through,” said Foggo, commander of U.S. 6th Fleet.

The admiral spoke to reporters on a conference call after a recent visit to Odessa, Ukraine, where he helped kick off the annual Sea Breeze naval exercise. The joint U.S.-Ukrainian training has brought together roughly 1,300 personnel from 11 nations for maritime tactics such as interdiction, anti-submarine warfare and search and rescue.

The U.S. is contributing its guided-missile destroyer Donald Cook and a P-3C Orion maritime patrol aircraft to the exercise. Seventeen other ships are participating, including the Ukrainian frigate Hetman Sahaidachny, the flagship of the fleet.

Foggo said he met with Ukraine’s prime minister, Arseniy Yatsenyuk, who expressed interest in modernizing his navy and asked about the costs of a shipbuilding program.

The Ukrainian navy already has its hands full, with many of its forces deployed near the port city of Mariupol, which is close to fighting between Ukraine’s army and Russian-backed separatists.

As expected, Russian ships have already made themselves known to ships passing through the Black Sea as part of the exercise. Russian media have skewed the scope of the exercise, Foggo said, and it’s possible Russia may hold a counterexercise as Sea Breeze drills begin in earnest next week.

But in a positive turn, Foggo said, the Donald Cook was hailed back from the bridge of a Russian frigate it met after crossing the Bosporous, the entry point to the Black Sea.

That’s an improvement from recent interactions between Russian ships and U.S. or NATO counterparts, he said, in which the Russians refused to respond to what are known as hail and queries. The Navy was optimistic after a Russian delegation visited 6th Fleet headquarters earlier this year to air complaints and discuss avoiding accidents, but Foggo said Russia’s practices have yet to change.

He said the situation might improve if Black Sea navies adopted the code of conduct agreed to by Western Pacific nations, including the U.S., last year. Known as the Code for Unplanned Encounters at Sea, or CUES, the nonbinding agreement sets a standard protocol of actions at sea, including communications and maneuvering instructions.

“It is another methodology for communicating intent,” Foggo said. “We use it all the time with the People’s Liberation Army Navy (of China). It could be something that could be extended to Black Sea nations.”

Russia and the U.S. currently act under the bilateral Incidents at Sea agreement, signed in 1972 to avoid confrontations between the Soviet Navy and the U.S.

Foggo said that despite the Ukrainian navy’s recent losses, the foundation is solid for the future.

“What they lost was capacity,” he said. “They lost numbers. But what they retained was the professionalism of those who decided they were with Ukraine.”

beardsley.steven@stripes.com Twitter: @sjbeardsley