From When the Shooting Stopped: August 1945, by Barrett Tillman (Osprey, 2022), Kindle pp. 208-210:
Meanwhile at sea, probably the last naval engagement of the war was fought off the China coast. On the morning of August 21 two sailing junks with American-Chinese crews were en route from Haimen to Shanghai. They were attached to the clandestine Sino-American Cooperative Organization, supporting guerrilla operations in Asia.
Lookouts sighted a large junk ahead; then the stranger came about, unmasking its armament, and opened fire.
Unknown to the two U.S. skippers – Navy Lieutenant Livingston Swentzel, Jr. and Marine First Lieutenant Stuart L. Pittman – their black-painted rival was a potent adversary. It carried a 75mm-pack howitzer, six machine guns, and more than 100 rifles for the 83 Japanese soldiers on board. Swentzel was a 35-year-old New Yorker with a degree from William and Mary whose excellent academic education ill prepared him for the situation.
The enemy’s first round was eerily accurate, severing Swentzel’s foremast to the consternation of most of his crew. Four Chinese were killed or wounded and the rudder damaged. However, Swentzel radioed Pittman, who coordinated the response. And in a brief moment of recalled glory from the age of sail, Swentzel hoisted the Stars and Stripes before returning fire.
Closing to 100 yards, the Yanks opened up with their heavy weapons – two bazookas intended for antitank action rather than naval warfare. One of Pittman’s sailors took two rounds to get the range, then knocked out the Japanese cannon, but both sides retained automatic weapons. After holing the enemy vessel, Swentzel directed Pittman alongside the Japanese and gave an order that John Paul Jones would have approved 170 years before: “Prepare to board!”
Hull to hull, Pittman’s half of the seven Americans and 20 Chinese led their attack with a hail of hand grenades to kill or disperse the superior Japanese numbers. With the Marine in the lead, a brief, violent skirmish subdued most of the remaining enemy, driving others below decks. More grenades followed down the hatches, forcing the survivors to surrender.
After 45 minutes the issue was settled, climaxing when the opposing skippers clashed hand to hand, with Pittman victorious. Before he expired, the Japanese officer told the Chinese that he had thought the junks were pirates. Americans and Chinese sorted the Japanese casualties, reckoned at 44 dead and 35 wounded. The Allies lost four dead and six injured. Swentzel and Pittman reversed helm for Haimen, and delivered their prize and prisoners to the Chinese before proceeding to Shanghai. Both skippers received Navy Crosses for their utterly unique action.