The Ukrainian Navy patrol boat zipped across the Black Sea, its double-barreled, 25-millimeter machine gun locked on the horizon. The enemy, Russia, was nowhere in sight, yet ever-present. In the command room, Captain Mykhailo and his crew scanned screens showing color-coded zones marking Russian mine-laden waters and red arrows tracking drones prowling the area.

The crew’s mission was to defend the waters off Odesa, Ukraine’s largest Black Sea port city, and keep them safe for commercial traffic. It has been grueling work — clearing Russian mines by day, shooting down drones by night — but after more than a year of patrols alongside other Ukrainian navy vessels, they have succeeded.

The Russian Navy has been pushed far from Ukrainian shores, allowing Ukraine’s commercial shipping to rebound to near prewar levels. On Tuesday, the fruits of Captain Mykhailo’s efforts materialized on the horizon: the silhouette of a 740-foot, Panama-flagged ship gliding toward a Ukrainian port to be loaded with grain.

“Big ship. Nice,” said Captain Mykhailo, speaking on the condition that only his first name and rank be used, in keeping with Ukrainian military rules.

Kyiv and Moscow committed to a cease-fire on the Black Sea last month during separate U.S.-mediated talks, but Ukraine’s military and commercial achievements in those waters have led many in Odesa to ponder this question: Does Ukraine have anything to gain from such a truce?