Mountbatten Medallic History of Great Britain and the Sea Medal: Rattler and Alecto Test the me…

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Mountbatten Medallic History of Great Britain and the Sea Medal: Rattler and Alecto Test the merits of Screw Propulsion

AssociatedAssociated with Lord Mountbatten of Burma (Frogmore House, Windsor, England, 1900 - 1979)

Medallist John Pinches, Medallists

DateMay 2004

Object NameMedal

MediumSterling Silver

ClassificationsMedals

AcquisitionPresented in 2004 by Dr Joan M Burrell.

LocationView by Appointment - Aberdeen Treasure Hub

Object numberABDMS072500.59

Keywords

About MeThe substitution of the screw propellor for the paddle was a crucial step in the development of the steamship in the first half of the 19th century. The process by which the screw propellor was invented and adopted, however, was a long and tortuous one, which culminated in success only after a lengthy period had elapsed, during which there was general skepticism concerning this new device. Nowhere was this more marked than in the British Admiralty, where the merits of the many competing types of propellor were anxiously debated for a long time.
There were many claimants to the title of inventor of the screw propellor, but perhaps Francis Petit Smith deserves to be regarded as the most resourceful and ingenious in gaining acceptance for this novel mode of propulsion. Smith had no technical training but nevertheless undertook a long series of experiments with small-scale models which ultimately convinced him of the merits of his design.

From farming in Kent, Smith moved to London and, at the age of28, built a launch named Francis Smith, powered by a small steam engine which drove a wooden double screw of his own devising and for which he had taken out a patent. During trials on the Paddington Canal the propellor broke in two, and Smith observed that the shortened propellor increased the speed of the vessel. His discovery fired in him an even greater enthusiasm, and he was able to induce a banker and a shipbuilder to form with him a joint-stockcompany, under an Act of Parliament granted in 1839, called The Ship Propellor Company. At a cost of £10,400 the firm built the wooden screw steamer Archimedes which made demonstration voyages, including a spell on the packet run from Dover to the Continent. It was this vessel, and a successor built by the same firm called Novelty, which were instrumental in drawing the attention of the Admiralty to the merits of Smith's propellor.

As a consequence, the Admiralty was induced to undertake experiments and trials in which the paddle sloop HMS Alecto and the screw sloop HMS Rattler were built in order to test the claims of the competing forms of propulsion. An exhaustive series of trials in 1845 demonstrated the advantages of the screw, and it was the ninth trial which caught the imagination of the general public. In this the two ships were secured stern to stern and pulled against each; other, with the result that HMS Rattler towed HMS Alecto stern first against the full power of the latter's engines at a speed of nearly three knots.

Although the merchant marine soon adopted the screw for most purposes except towing, acceptance by Admiralty and the Government was somewhat reluctant. Many technical problems remained, notably the need to design higher-speed engines to power the propellor, and the need for appropriate gearing between engine and propellor shaft. Finally, vibration problems had a harmful effect on the wooden hull: the building of iron hulls was the necessary complement to the adoption of the screw propellor, in the development of which Francis Petit Smith exhausted a fortune.

The Mountbatten Medallic History of Great Britain and the Sea, John Pinches Medallists Ltd.