The Reed water tube boiler was a type of water tube boiler developed by J. W. Reed, manager of the engine works at Palmers Shipbuilding and Iron Company of Jarrow, England, where it was manufactured from 1893 to 1905. At this time, Palmers was a vertically integrated business: in its shipyard at Jarrow, using iron ore from its own mine in North Yorkshire, it produced the iron and steel needed for its ships, and engines and boilers of its own design. Intended for use in the steam propulsion of ships, the Reed water tube boiler was similar to other boilers such as the Normand and Yarrow, themselves developments of the du Temple boiler. These differed from locomotive boilers, also known as "fire tube boilers", in that, whereas the fire tube boiler consisted of a cylinder filled with water, which was heated by tubes passing through it carrying exhaust gases from a furnace, in the water tube boiler the situation was reversed, with water passing through steam-generating tubes mounted directly above the furnace. Advantages of the water tube boiler included comparative lightness and the ability to run at higher pressures. About 170 of Reed's water tube boilers were installed in ships of the Royal Navy, in two of which they were installed to replace boilers rejected by the Admiralty. Design The Reed water tube boiler was developed and patented in 1893 by J. W. Reed, manager of the engine works at Palmers Shipbuilding and Iron Company, which manufactured it. By the last quarter of the 19th century Palmers had become one of Britain's largest shipbuilders and, during its operation between 1851 and 1933, it produced "more than 900" ships. However, it was a vertically integrated business: from about 1857 it possessed its own source of iron ore, mined near the North Yorkshire coast in the vicinity of Whitby and Saltburn, and, according to the local historians Jim Cuthbert and Ken Smith, "it was said that [Palmers' shipyard] brought in iron ore at one end ... and sent it away again at the other end in the form of finished ships." Thus the Reed water tube boiler was a natural addition to the company's output, which had previously included other designs of boiler, such as the Belleville boiler, besides steam engines. It was similar to its antecedent the du Temple boiler, and other developments from it such as the Normand and Yarrow