John Penn was born at
Greenwich in 1805. His father was established here as an engineer and
millwright, working mainly in corn and flour mills. Penn entered his father’s
works at an early age. His father died in 1843, and sole possession of the
works passed to Penn. For some years previously he had had sole management of
One of the earliest
engines which he produced was the grasshopper engine. A 6 horse power
grasshopper engine was the first steam engine to power the machinery at the
40 horse power beam engines fitted in the steamers ‘Ipswich’ and ‘Suffolk’ were
probably the first marine engines to be designed and built by Penn. These
engines, with some modifications, were fitted to the four passenger boats plying
on the Thames between London and Greenwich.
Penn next turned his attention to
improving the oscillating engine. In 1844 he replaced the engines of the
Admiralty yacht, ‘Black Eagle’, with oscillating engines of double the power,
without increasing either the weight or space occupied.
Another major innovation in marine
engineering was Penn’s introduction of trunk engines for driving screw
propellers in vessels of war. Here space was at a premium, and the engines had
to be placed in as safe a position as possible. He kept the engines low in the
vessel, and drove the screw directly. The first ships fitted with this engine
design were the ‘Arrogant’ and the ‘Encounter’, and by the time of Penn’s death
in 1878, 230 ships had been fitted with such engines.
Penn was also responsible for
introducing wood bearings for screw-propeller shafts, presenting two papers on
the subject to the Institution in 1856 and 1858. He was also associated with
the application of superheated steam in marine engines, presenting a paper on
this subject in 1859.
John Penn became a Member of the
Institution in 1848. He served as President in 1858-1859, and again in
1872, he handed over management of the works to his two eldest sons, retiring
altogether in 1875. He died in 1878.