In 1912 she was acquired by Lord Penrhyn and converted into a luxury yacht and spent two years cruising the Mediterranean.

Mary B Mitchell was built by Paul Rogers in 1892 at Carrickfergus, as a three-masted topsail schooner.

She was owned by Lord Penrhyn and served for a period as a yacht, before being put to work as a coaster,[3] transporting china clay from Cornwall.

In 1916 three Arklow schooners were requisitioned by the Admiralty to be used as Q-ships, they were: Cymric, Gaelic and Mary B Mitchell.

The expectation was that the U-boat would approach the apparently abandoned ship and would be surprised and sunk when the guns were revealed and opened fire.

The Naval Intelligence Department stated that none of Mitchell's encounters resulted in the destruction of any U-boat.

[10] After the war, it was concluded that Q-ships were greatly overrated, diverting skilled seamen from other duties without sinking enough U-boats to justify the strategy.

[15] At the outbreak of World War II there were only 56 ships on the Irish register, 14 of those were Arklow schooners.

[16] Mary B. Mitchell carried food exports and pit props to Wales; returning with cargoes of coal.

Britain had declared the Bay of Biscay to be an "exclusion zone"; their objective was to prevent supplies from reaching Germany, in particular Japanese exports.

However, it was difficult for sailing ships to adhere to this straight line, particularly in the stormy conditions, common in the Bay of Biscay.

Mary B. Mitchell made five of these voyages, carrying food to Britain, then British coal to Lisbon, returning with the American cargo to Ireland.

Arthur Dowds was captain James Harte was sailing master and Patrick Brennan was first officer.

She vanished with all hands; she may have hit a mine, been torpedoed by a U-boat or bombed by the RAF who were enforcing the blockade of Germany, as was the MV Kerlogue on this same route.

[23] The Mary B Mitchell is commemorated in Bangor, Wales, by a memorial plaque and a bronze weathervane which adorns the city's new shopping precinct.