Samuel Bentham was one of two surviving siblings of Jeremiah Bentham. His father was an attorney, and his older brother was the philosopher Jeremy Bentham, five other siblings having died in infancy or early childhood, and their mother dying in 1766. At the age of 14, Bentham was apprenticed to a shipwright at Woolwich Dockyard, serving there and at Chatham Dockyard, before completing his 7-year training at the Naval Academy in Portsmouth.
In 1780 he moved to Russia, where he was employed in the service of Prince Potemkin, who had an establishment designed to promote the introduction of various arts of civilization. Initially hired as a shipbuilder, he soon discovered other opportunities to use his talents as an engineer and inventor, constructing industrial machinery and experimenting with steel production. He also designed and constructed many novel inventions, including an amphibious vessel and an articulated barge built for Catherine the Great, and the first Panopticon.
He was also decorated for his part in a decisive victory in the war against the Turks, and commanded a battalion of 1,000 men in Siberia. He eventually came to have complete responsibility for Potemkin's factories and workshops, and it was while considering the difficulties of supervising the large workforce that he devised the principle of central inspection, and designed the Panopticon building which would embody that principle and was later popularized by his brother Jeremy.
In 1782, Bentham travelled along the Siberian route to China, visiting Kyakhta and its Chinese pendant Naimatchin, and then spending over a month at the border fluvial city of Nerchinsk, where he was able to study Chinese ship designs, particularly those of junks. Back in Europe, he campaigned for the introduction of watertight compartments, an idea which he acknowledged he had got from seeing large Chinese vessels in Siberia.
Samuel returned to England in 1791, and for the next few years was involved with his brother Jeremy in trying to promote the Panopticon scheme and he designed machinery for use in it. It was during this period that he met his future wife, Mary Sophia Fordyce, the daughter of Scottish doctor and scientist George Fordyce, a friend of Jeremy Bentham. The two were married in October 1796.
In 1795 the Lords Commissioners of the Admiralty asked him to design six new sailing ships with "partitions contributing to strength, and securing the ship against foundering, as practiced by the Chinese of the present day". These were built by the shipyard of Hobbs & Hellyer at Redbridge, Hampshire, and incorporated a number of other novel features such as interchangeable parts for masts and spars, allowing easy maintenance while at sea.[Note 1]
In March 1796 Bentham was appointed Inspector General of Naval Works, responsible for the maintaining and improving the Royal dockyards, a post which involved a lot of travel. He produced a great many suggestions for improvements, which included the introduction of steam power to the dockyards and the mechanisation of many production processes. However, his superiors at the Navy Board were resistant to change and many of his suggestions were not implemented.