The First Anglo-Dutch War was barely a few months old, the Commonwealth of England and the Dutch Republic suddenly fighting over trade, flags and pride. Personal feeling had not yet caught up to politics. Ayscue, now General-at-Sea for Parliament, and De Ruyter, lately appointed Vice-Commodore of the confederate Dutch fleet, knew each other from older voyages and easier years. The war found De Ruyter in command of a squadron of twenty-three warships and six fireships, six hundred guns and roughly seventeen hundred men, much of it in poor repair. He had been ordered to escort a fat convoy from Zealand out to the Atlantic. Ayscue had been chasing him for weeks, hoping to ignore the warships and snap up the merchantmen as prizes. The Dutch had never been the prize.

On 15 August lookouts off Plymouth spotted Dutch sails on the southern horizon. By midday on the 16th, off the Brittany coast, Ayscue swept down from the north with the wind at his back, the textbook position of advantage. De Ruyter did the unexpected: he turned his warships out of the column, sliding between his merchantmen and the English. Ayscue's heaviest ships, including his flagship George and Vice-Admiral William Haddock's Vanguard, had already raced ahead in their hunger for stragglers and could no longer form a line of battle. Around four in the afternoon the two fleets crossed - both sides afterward claiming to have broken the other's line - and the engagement collapsed into a smoke-choked melee. Chain shot tore through Dutch and English rigging alike.

The largest Dutch ship was the East India Company warship Vogelstruys, heavily armed by Dutch standards with a tier of eighteen-pounders. She got separated, was set upon by three English vessels at once, and was boarded. Her crew was on the brink of surrender when her Frisian captain, Douwe Aukes, declared that he would blow the ship up before he struck his colours. Faced with going down with her, the crew rallied, drove the English boarders back over the rail, and shot two of the attacking ships into sinking condition. Watching his vanguard mauled, Ayscue lost his nerve. He broke off and ran for Plymouth to repair. The English fireship Charity, captained by Simon Orton, lit itself ablaze to scare the Dutch away from the wounded Bonaventure - bought with her own destruction.

No warship was lost on either side, but the human price was heavy. The Dutch counted around sixty dead and fifty wounded. The English accounts vary - one suggests as many as seven hundred casualties, most of them from the failed assault on the Vogelstruys; another lists ninety-one dead. Among them was Ayscue's flag captain Thomas Lisle. Rear-Admiral Michael Pack had a leg amputated on a surgeon's table and died of his wounds soon after. De Ruyter pressed his pursuit through the next morning, hoping to pick off English ships under tow, but Ayscue rallied his council of war and got the bruised fleet back to Plymouth on the 18th. While the English nursed their hulls and pride, the Dutch convoy of sixty merchantmen and ten warships slipped clear through the Channel and into the Atlantic, exactly as De Ruyter had been ordered to see them through.

Plymouth had expected a coronation and got an embarrassment. The Dutch populace, who had barely heard of De Ruyter before, took to the streets to celebrate. Sailors started calling him the Sea Lion. Ayscue, blamed for poor handling and tainted by old royalist sympathies, lost his command. Parliament would push English admirals toward the harder business of naval dominion in the battles that followed - the Kentish Knock, the Gabbard - but the lesson of Plymouth had been delivered. A smaller fleet with a clear mission and a captain willing to risk his ship rather than his colours could beat a larger, richer one chasing prizes. Today the waters off Plymouth Sound see container ships and Channel ferries instead of fireships, but somewhere out toward Brittany the old battlefield is still there, marked by no monument, remembered mostly in Dutch.