HMS Syrtis, Captain George Crome commanding, was a British frigate which chased a spanish privateer into the Bay of Ferrol during a gale at the time Acting Lieutenant Hornblower was a prisoner of war at Ferrol. The privateer struck the rocks of Dientes del Diablo, or the Devil's Teeth. Hornblower convinced the garrison commander and locals to attempt a rescue of the surviving crew members of the privateer. After successfully rescuing three of the crew, after which one died in the rescue boat, Hornblower's crew was blown to sea during the gale as it was too dangerous to attempt a landing.
The next day the crew was picked up by Syrtis. After explanation by Hornblower, Crome agreed to send the spanish seaman who died an appropriate burial at sea, and to return Hornblower, his crew, and the two rescued seaman back to A Coruña under flag of truce.There was no British naval ship by the name of HMS Syrtis until 1943, a submarine.
Mr. Midshipman Hornblower: The Duchess and the Devil.
HMS Syrtis P241 (1943) in Wikipedia