Harriet Pinckney (more often spelled Pinkney in official naval records) was a fast, new, British brig of iron with coppered bottom and a 90-horsepower auxiliary steam engine; she was completed in Richardsons yard at Middlesborough in Yorkshire, 23 July 1862, registered at London next day and was alleged to have done 18 knots on her builders' trials. Because of her speed and other characteristics she was immediately bought up by Confederate agents working through Fraser, Trenholm & Co., Liverpool, and Comdr. James D. Bulloch, CSN, as secretly as possible. Her "owner," therefore, was a "Mr. Thomas Sterling Begbie of 4 Mansion House Place, London," to whom Lloyd's Register adds a "Mr. R. Hamilton" [cf. Agrippina]. But "Begbie" was a red light to Consul F. H. Morse, who lost no time in relaying the new Confederate steamer's particulars to Washington : he described her as having "one deck, two masts, brig rig, elliptic stern, clench build, no gallery, no head; iron frame." He also seemed to be aware that she promptly loaded 24,000 rifles, 18 cannon and a cargo of other vital munitions in the Thames, transhipped from the Sylph, just in from Hamburg, and was off about 9 August for Bermuda.
On 8th and 9th August 1862, assiduous Consul Morse sent Secretary of State Seward sketches and descriptions of a new mine which he thought "H.P.," as she was frequently called, would certainly be carrying: these "infernal machines or torpedoes" were "an invention for destroying ships in harbor" and he warned that "if the explosion takes place at the right distance, the consequences will be most horrible." The horrendous contraptions employed an unknown "poisonous fluid and explosive balls filled with poisonous matter." While it is doubtful that this intelligence was released in Bermuda, "H.P." caused a considerable stir there on 5 October when the whole populace turned out to watch her and fellow blockade-runner Minho try to escape, only to be chased back into port by USS Sonoma, there for that purpose.
Harriet Pinckney was diverted from her transport functions through the blockade when a tender was chosen for CSS Rappahannock (q.v.) but when the raider was held indefinitely in port at Brest, "H.P." was no longer seen in the area and presumably disappeared back into the demimonde of the blockade runner to deliver essential cargoes to the Confederacy.
