This is the Royal Navy armoured frigate HMS Agincourt, launched 1865. She had five masts capable of full sail, a steam-driven propellor, and her hull was covered with 5-inch thick wrought iron. At half a million quid, she was one of the most expensive ships of her day.

With her engines running full tilt she managed 14 knots (16mph; Nelson's HMS Victory, built a century earlier could sail at 12 knots) but full speed rendered her unsteady.

Under full sail she could only manage 9 knots (about 10 mph: you could sprint faster) bc her propellor couldn't be lifted out of the water and so acted as drag, making the ship "almost wholly unmanageable". Her iron plating made her extremely sluggish.

She ran aground near Gibraltar and was too heavy to be towed back into deeper water: all her coal was jettisoned and all her guns removed to make her light enough. She never fought in any actual naval conflict. Eventually the navy took down her masts and used her as a coal hulk.

Money well spent, I think we can agree.

This has been today's 19th-century research rabbit-hole-I-didn't-expect-to-go-down. Thank you for your attention.