New River Steamers.

Thames Star, Volume X, Issue 3097, 21 January 1879, Page 2

New River Steamers.

We have been shown photographs of some light draft steamers recently turned out by Messrs Yarrow and Co., at their Poplar Works. The photographs were sent out to a gentleman resident at the Thames by the last mail, and the character of the boats may be judged from the following descriptions :—

DESCRIPTION OF A STEIN ITHXEL, BTEAMEB, Built to the order of Messrs Stephenson, Clarke and Co., by Messrs Yarrow and Co., for the Hiver Magdelena. Messrs Yarrow and Co., steam launch builders, of Poplar, have for some time turned their attention to the construction of steamers specially suited for river navigation, having an exceedingly shallow draft. This firm has just completed four vessels of a special type for this purpose, of which the following are a few particulars^ of one:—Length, 100 feet; beam, 24 feet; speed, 12 miles an hour. This vessel has been built of Bessemer steel throughout, including frames, deckhouse bulkheads, &c, and will hare the remark* ably shallow draft of 12 inches when in working trim and steam up. There is a flush deck from end to end, the boiler being placed on this deck near the bow and the engines qu?te aft, driving a stern paddle wheel 12 feet in diameter and 17 feet wide. The engines have cylinders 13 inches diameter by 36 inches stroke and work at is, pressure of ISOlbs per square inch. A system of diagonal trussing is adopted throughout the vessel similar to what is so frequently done by American engineers, but which, is almost unknown in this country; by this meant a given amount of strength is obtained with less weight than by any other method. Not only do these diagonal trusses increase the strength of the hull, but by screwing them up tight the vibration, which is a difficulty in light-built boats, is greatly reduced—in fact, this system enables a much lighter construction to be used than would otherwise. be practicable. There is an upper deck, upon which, are placed the various cabins. There are four rudders at the stern, all being actuated together by the steersman from a pilot house placed near the bow. The vessel inspected is destined for the Eiver Mag. delena, and it being impossible to sail such a craft across the Atlantic, it has been built for shipment in pieces, it was, however, entirely put together at Messrs Yarrow's Works and the machinery all in its place, was tested under steam. For river navigation, under some conditions, stern wheel steamers have many advantages over other modes of propulsion; this is proved by their frequent adoption in America, where river navigation has been brought to a greater degree of perfection than elsewhere. One advantage <■ which a stern wheel steamer possesses is clearly that the wheel is well protected and not liable to get damaged from floating timber. Also,; the total width is less, which in some cases is important. Touching <the speed, it is found that in deep water a side wheel steamer goes faster by about a mile an hour than a stern wheeler of the same size and power; but on the other hand, when passing over rapids the latter has the advantage, the cause of this must be looked for in the fact that the paddle wheel being as it were away from the vessel, does not pass through the worst parts of the rapid ait the same time ai the body of the boat. Messrs Yarrow and Co., who have built many side paddle steamers drawing as little as Biz inches of water, say, they nre prepared to construct stern wheelers having a like shallow draft to meet special cases that may require it.

A LIGHT DBAUGHT STBAMBB, The increasing necessity for effecting communication between distant placet in foreign countries by means of water transit has, where such means of transit ex* ists, led to a demand for vessels of a light draught in order to navigate very shallow rivers. Builders have gone on reducing the draught from two feet to one and even less, but as civilisation spreads the navigation of still shallower streams and the supplying of still lighter draught boats become necessities. It thus happens that Messrs Yarrow and Hedley, of Poplar, have been engaged to design and con* struct some steamers of exceptionally light draught for the navigation of the upper waters of one of the rivers in Brazil. These boats are intended chiefly for the conveyance of passengers, and the first of them has just been launched, and made a satisfactory trial trip on Saturday last. In all probability she is the shallowest draught steamer ever built, her draught, with steam up and fully equipped/being only seven inches. This formed one of the conditions imposed upon her builders. The others were that she should not draw* more than nine inches of water with 20 persons on board, and that she should be of such a size as to be capable of being carried whole on a ship's deck to the Brazils. The steamer has, therefore, been built with a flat bottom, and has a length of 45 feet, and a beam of eighfcjaefc with a depth of two feet. tffo xi s propelled by a pair of paddlesi Mfi 1- in diameter, 2ft, 9in. breast, and each having eight floats. Her paddles are driven by a pair of inclined direct-acting engines, with cylinderssJin. in diameter and 10in. stroke. She is roomy and comfortable both fore and aft of her engines, there being accommodation for about 40 persons in all. Upon her trial trip on Saturday, with 11 persons on. board, she drew B|in. of water. Her engines ran at an average rate of 80 revolutions per minute, which gave her a speed of about eight miles per hour. On her first contractor's trial she made the same' speed with the same number of revolutions, and with 1301b. steam, the stated consumption of fuel being 401b of coal per hour. The run made with the little craft from the Temple to Greenwich and back on Saturday was thoroughly satisfactory and demonstrated both her speed and handinesi. Now that it has been satisfactorily shown that such a light draught is perfectly practicable, it will probably follow that districts hitherto unexplored and lying up rivers previously deemed unnavigable will be opened up and new sources of commerce developed.— Times, October sth.