Phoenix, a steamer constructed by Messrs. Scott, Sinclair, and Co., for steam vessel Don Juan, constructed by Messrs. Girdwood & Co., of Glasgow, plying between Cape Town and Algoa Bay, at the Cape of Good Hope. Fig. 47. Fig. 50. of which we shall give all the best specimens. But a good number of boilers upon the common flue plan are still made, so that some specimens of them are indispensable; and, indeed, there are still far more flue boilers in use than there are of any other description. In most of these boilers it is a fault that the furnaces are made too long and narrow, and the consequence is, that it is impossible to fire them on a long sea-voyage, especially in stormy weather. It is much preferable to restrict the furnaces to a moderate length, and give the bars a considerable elevation, so that they always be well covered with coal at the after ends. When the furnaces are very long, a good deal of air generally escapes into the flues at the after end of the bars, the effect of which is materially to lessen the generation of steam. Scale three-tenth inch=2 feet. BOLLERS OF STEAMER EAGLE, BY MESSRS. CAIRD AND CO. Elevation and Horizontal Section. 310 BOILERS OF STEAMERS THAMES AND MEDWAY, BY MESSRS. MAUDSLAY AND FIELD. Horizontal Section through Furnaces. BOILERS OF STEAMERS THAMES AND MEDWAY, BY MESSRS. MAUDSLAY AND FIELD. Longitudinal Section. Figs. 71, 72, and 73 represent the boilers of the Thames and Medway, two vessels of large size, constructed by Messrs. Maudslay and Field for the Royal Mail Steam Packet Company. The boilers of these vessels have been very successful, and are among the best specimens of the flue boiler as applicable to marine engines hitherto produced. We do not know of any boiler of this kind that engineers may imitate with greater safety, as regards their power of generating steam, though there are many specimens distinguished by a greater durability. In some of the boilers recently introduced in the Royal Mail Steamers, the furnaces stand athwartships, and the plan is attended with the material advantage that the coals trim more easily; for the coal reserve in this arrangement situated behind the boilers, and another depôt standing between the boilers and the engines, communicate immediately with the stoke-holes, whereby an easy transfer of the coal becomes accomplishable. |