To refresh people's memory on the Captain, she was the world's first ocean-going turret ship. She was armed with 4 12" and 2 7" rifles in turrets, and armoured with both belt and turret barbette.
However, what relatively few know about was the near-disaster that took place on the early morning of 7 September 1870. Cruising off Cape Finnistere, Captain heeled over unexpectedly hard due to a squall and several men lost their lives - only the prompt action of Adm. Leonard Childers (then a Midshipman) in casting away the topsheets without orders prevented her from capsizing.
On board Captain at the time were Cowles, the aforementioned Adm. Childers as a midshipman, and dozens of other names of major or minor importance (...though none quite so major as the two I've highlighted). My question is - what would have happened had Childers not managed to cast away the topsheets in time?