The nuclear age dawns
‘NS Savannah’ undertook its first voyage from the US to Europe
The big news in ‘The Motor Ship’, August 1964, was the US nuclear powered merchant ship, ‘Savannah’ undertaking its first voyages, including visiting several European ports.
Her machinery was described as “the most costly form of marine propulsion, but what some contend will in due course prove to be the forerunner of many nuclear powered ships.” The 7,900dwt ship had been nine years in building, at the New York Shipbuilding Corporation, under the auspices of the US Department of Commerce, the Atomic Energy Commission and naval architects George G Sharp. The ship, which had accommodation for 60 passengers as well about 600,000ft³ of mixed cargo, was equipped with a Babcock pressurised water reactor of 80MW, producing steam to drive a 22,000shp De Laval turbine. At full power, Savannah was capable of 20 knots.
According to the lead article, the most intriguing aspect of the ship was the ease of controlling the nuclear power plant. The prevailing belief was that such a ship would need a team of nuclear scientists to drive her, but of the the 25 engineers on board, although most had extensive sea-going experience, only a handful had known anything about nuclear power before embarking on a three month training course, including simulator time. Although the machinery control room contained much unfamiliar instrumentation, the wheelhouse was little different from any other high-specification cargo liner of the time.
In the same issue, Babcock and Wilcox, the British arm of the makers of the Savannah reactor, described a more economical and more compact pressurised water reactor it had developed for ship power. This was due to housing the boiler or heat exchanger within the pressure vessel. A complete 20,000shp steam plant, considered to be the most economic size, weighed 510t, compared with the 2,450t of the Savannah plant. The new version, known as consolidated nuclear steam generator (CSNG), was said to be ready for production as a merchant ship power plant.
Among the other ships described in the issue was a Dutch cargo liner with a six-cylinder engine capable of 18,000bhp. The Koudekerk, a 12,200dwt open/closed shelterdeck cargo ship, was built by Van der Giessen-de Noord for the United Netherlands Navigation Company, and powered by a Stork SW6x85/170 engine. Although rated in service at 14,200bhp at 117.5rpm, the engine had attained 18,000bhp on testbed trials, which was believed to be the highest rating ever achieved by a production six-cylinder engine. Unusually for a ship of this era, the hull had been designed for high hydrodynamic efficiency to take full advantage of the high engine power. A long faired propeller boss was fitted which allowed the propeller to work in fairly open water, with a claimed 12% gain in efficiency. The designers – Royal Netherlands Steamship Co - decided against fitting a bulbous bow, this being considered an impediment under light loads, but were said to be studying a new type of bulb that would be able to be immersed in most conditions of draught, and if model tests proved successful would be incorporated in future ships of the class.
The six-cylinder engine was said to be of compact size for its power output, with despite the engine room being only as long as the ship was wide, the main and auxiliary machinery was well accessible for maintenance.
Finally, the advent of computer aided design was just around the corner. A company called International Shipping Information Services (ISIS) was offering a service that could search a database of about 40,000 ship designs stored on its ICT 1500 computer and print a list of those most suitable for any given application.