JIM FLOWER’s long career as a marine engineer involved him in a wide variety of important projects which included — after he had left the Navy — restoration of the propulsion machinery of Isambard Kingdom Brunel’s great steamship the Great Britain.

He joined the Royal Navy from Blundell’s School in 1941, and served during the war in the cruiser Norfolk and the battleship Duke of York. In 1948 a tour as an engine room watchkeeping officer in the cruiser Liverpool was followed by a five-year stint on the staff of the Engineer-in-Chief of the Fleet. This led to a first “charge job” in 1955 as the engineer officer of the frigate Whitby, the leading ship of the successful class of 18 Type 12 anti-submarine frigates.

Despite the inevitable teething troubles attendant upon building and commissioning a new design of steam plant, Flower rose above the challenges and, as a contemporary recorded, “soon had Whitby running like a sewing machine”.

Promoted to commander in 1957, Flower joined the recently formed nuclear propulsion development team under the Rear-Admiral Nuclear Propulsion — a project chief created in American management style to overcame inertia and confused accountability. Flower worked on the development of Dreadnought, Britain’s first nuclear submarine, and the concomitant training and personnel issues arising from this expanding and highly technical programme, until 1961.

Two years at sea as the engineer officer of a frigate squadron were followed by tours at Cammell Laird’s shipbuilders and at the Admiralty. After promotion to captain, he was the Western Fleet’s senior engineering staff officer and, from 1970, commanded the nuclear reactor testing and training establishment at Dounreay in the North of Scotland, by which time a fraught British nuclear propulsion programme had settled down, and more or less divested itself of American influence and hardware.

He next spent four years based at the Ministry of Defence in Bath as Deputy Director (Design) for marine engineering with the Director-General (Ships). Perhaps more than any other single person, he was responsible for the success of the “marinised” gas turbine programme, initially based on the Type 14 frigate Exmouth which was rebuilt as a gas turbine-driven ship and used as a test-bed to overcome the host of design difficulties that confront aero engines when translated to a hostile shipborne environment.

This programme placed the Royal Navy well ahead of other nations and has been compared in importance to the introduction of the steam turbine, the Exmouth being likened to Sir Charles Parson’s Turbinia that so astonished with its speed the Diamond Jubilee Spithead Naval Review in 1897. Within a few years, all major Royal Navy new construction, including aircraft carriers, were gas turbine-driven.

Described by his superior officer as “an exceptional officer in both character and ability who is universally respected”, Flower was promoted to Rear-Admiral in 1975 and appointed Flag Officer and Port Admiral at Portsmouth. He returned to Bath for his final two postings as Director of Engineering (Ships) and Director of Post Design.

There he was very much to the fore in promoting the interests of Rolls-Royce in Japan, where British experience with overall “marinised” installations, particularly the fuel-efficient Olympus-Tyne combination, produced an edge over the competition. This led to Japan’s Maritime Self Defence Force becoming a better customer than the Royal Navy.

Flower was appointed CB on his retirement in 1980.

He is particularly remembered for his work in support of the engineering restoration of the SS Great Britain at Bristol, bringing his qualities of precision and organisation to a team of fairly eccentric enthusiasts. As a contemporary remarked: “If the meeting was for 10 o’clock, you could look out of the window and set your watch to one minute to as Jim Flower stepped across the caisson.”

The propulsion project will be complete in about three years’ time, and involves re-creating a machine which, because of — by today’s standards — a remarkably low steam pressure of 12lb per square inch, had to have huge cylinders in V4 formation driving an enormous crankshaft and, via a linkage rather like a giant bicycle chain, turn the propeller shaft at a maximum rate of 52 revolutions a minute for a speed of 12 knots.

Besides fundraising, Flower had to do much detective work as there are no original drawings. To enhance realism for visitors, the machinery has to be able to rotate under electric drive.

Flower also took a degree in mathematics with the Open University and was a respected and hard-working Liberal Democrat member of Bath and North-East Somerset Council.

He is survived by his wife, Martha Pyman, and their three daughters.

Rear-Admiral James Flower, CB, marine engineer, was born on July 5, 1923. He died on December 19, 2002, aged 79.