THE BOMARENG PROPELLER TRIED IN THE STEAMER "KEERA."

Lyttelton Times, Volume II, Issue 80, 17 July 1852, Page 11

THE BOMARENG PROPELLER TRIED IN THE STEAMER "KEERA."

[From the " Sydney Empire."]

This is the age of practical utility, but the event it is now our business to chronicle is one of the most remnrkable, as connected with the history of this Australian colony, that has hitherto occurred in its annals. Whilst the capitalists of Europe are embarking huge and expensive machinery in large vessels of fourteen or fifteen hundred tons burden, to be moved by screw propellers, they are all abroad as to the form most proper for the screw—on which the use and .efficient application of all depend—for working on the resisting power of water. The true principle for the construction of this has been derived from the aboriginal natives of Australia! The bomareng propeller had suggested the idea of an oblique double blade, possessing a small amount of surface, so placed as to be in equilibrium with reference to the centre of motion; but this seemed too unlike the common sort of propellers in use in vessels, so that, although models have been some time in London, and even exhibited at the Great Exhibition, the invention did not obtain even " honourable intention." It was too original, for it was aboriginal. Sir Thomas Mitchell's invention of-the Bomareng Propeller, as applied for the purpose of propelling a vessel through the water, has been tried, and the result has exceeded all expectations. By the permission of the owners of the " Keera," screw-steamer, an iron bomareng propeller, formed as nearly to the required proportions as the peculiarities of the vessel would permit, was fitted to the " Keera." Sir Thomas Mitchell's rules for the construction of the Bomareng Propeller depend on its having a diametor equal to the pitch. The diametor of the screw of the " Keera" is only five feet eight inches, and the pitch is eight feet, so that the propeller fitted to her necessarily differed materially from what it should be to give it a fair and complete trial. However, under every disadvantage, the experiment has met with complete success, and we heartily congratulate the inventor on this triumph of skill and perseverance, honourable to himself and to the colony at large. The " Keera" left the wharf on this trial trip, and proceeded to North Harbour with Sir Thomas Mitchell, Messrs. Smith and Croft, and a considerable number of influential and intelligent gentlemen on board to witness the result. We cannot give our readers who may be engineers, such an account as may satisfy professional men ; but we can state results :— When the " Keera" started, we perceived not a ripple under her stern; but when she got in full speed, it was evident that she was impelled by a new kind of propeller, from the tranquil appearance of the water astern, the curl at the bow, and increased speed—so much so that a friend of ours, who observed her from Woolloomooloo, enquired what was the matter with the " Keera," that she had set off like a race-horse. The distance given in an Almanac enabled us to keep a reckoning of the speed, and in running from Blue's Point to Pinchgut, she took 6m. 10s., deducting 4m. 20s. for stoppages, during which she took parties on board. As this must have retarded the remainder of that part of the run to Pinchgut, a distance given as 2117 yards, her rate then may be fairly computed at 10 knots an hour. In returning, she got over the same distance in five minutes, when steaming on the expansive principle, which rate gives rather more than 12 knots au hour. « Down the harbour the time could not be

noted conveniently, so exciting were the results? and so delighted were the parties on board in thus witnessing an entirely new invention, likely to be the harbinger of greatly accelerated speed to ocean steamers, first tried on the waters of Port Jackson. The bomareng, in its simplest form, had been tried several years since on the same waters, we believe, but this propeller, consisting of the divided bomareng, was •first tried in water on this occasion. We understand that the results, even with the very cramped form which the propeller was necessarily made to assume, in order to have the same pitch and diameter as the Keera's own screw, for the sake of a fair comparative trial of the respective merits of the two propellers, leave us no doubt as to the accuracy of the principle, and are sufficient, we understand, to prove that this is the true form which sea-going screw-propelled vessels must use, or something very near it, if they are to go at high speed. Twenty miles an hour with large vessels are said to be easily attainable with a propeller on this construction without multiplying wheels. This part of the inventor's plan, however, has reference to a method of fitting in the gearing, which has not yet been divulged. It will indeed be a subject of just congratulation when Anglo-Australians will begin to think and act for themselves, and deal with the elements, as they find them around in Australia, without blindly copying the appliances that belong to other countries and climates, and adopting in some cases the very dullness and blunders of the opposite hemisphere. The Keera will be put on the Patent Slip, to take off the Bomareng Propeller, and re-fit the screw, so that any persons interested in the matter will have an opportunity of making themselves acquainted with this new and interesting invention—the application of a rude weapon of savage warfare to a most important use in Arts and Civilisation.