1826 - following an apprenticeship with his father (John Penn 1770-1843), he constructed the steam gun invented by Jacob Perkins, which was shown to Wellington and other officers, taken to Paris, and later exhibited at the Adelaide Gallery, London. 1826 - elected an associate of the Institution of Civil Engineers. 1843 - approached the Admiralty with an unsolicited offer to install high-power oscillating engines in the Admiralty steam yacht Black Eagle. 1845 - became a member of the Institution of Civil Engineers. 1848 - developed the trunk engine which was subsequently installed in the pioneer screw frigate Arrogant. 1852 - a modified version of the high-power oscillating engine was fitted to the pioneer iron screw steamer the Great Britain. 1853-1856 - served on the Institution of Civil Engineers council. 1854 - in collaboration with Francis Pettit Smith, developed and patented the lignum vitae stern bearing. 1859 - arbitrated the quarrel between Isambard Kingdom Brunel and John Scott Russell over the Great Eastern. 1859 - was elected FRS. 1860 - helped to found the Institution of Naval Architects.