Section 103.—MARINE ENGINES (TYPES OF).
Many varieties will be found illustrated under [Section 32]. The following are modern types:—
[1895]. Diagonal paddle engines, for light draught vessels. May of course be either of two or three cylinder type and either high pressure or compound.
[1896]. One of the most favourite types of vertical overhead cylinder screw engines, with half standards and distance rods, one, two or three cylinders, simple or compound. The condenser is usually in the back standards and the pumps behind. Simplicity and accessibility are its chief advantages.
[1897]. Stern wheel, side lever engines, not often required in practice. The ordinary construction of horizontal engines usually accommodates itself for stern wheel driving. See [Nos. 575] to [579], &c.
[1898]. Double standard vertical overhead cylinder screw engines, the type commonly adopted for the heavier class of vessels, and frequently made for triple expansion. It is of very rigid construction, but not quite so convenient for accessibility to the working parts as [No. 1896]. The condenser and pumps are at one side, built into the standard, and the engines are handled from the opposite side or from an elevated platform.
[1899]. Overhead cylinder and distance rod type, the lightest and simplest form in use for small engines. Every part is easily seen and got at, and the top weight is reduced to a minimum.
[1900]. Is a variety of [No. 1896], with tandem cylinders and two cranks for triple expansion.
[1901]. Is also a variety of [No. 1898], with tandem cylinders for triple expansion. In this plan the intermediate stuffing box is got rid of by using two piston rods to the lower cylinder, coupled to the piston rod of the upper or high-pressure cylinder by a crosshead.
[1902]. Compound overhead standard engines, for twin screws.
[1903]. Diagonal twin screw engines.
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[1904]. Horizontal twin screw engines.
[1905]. Plan of cylinders as usually employed for [No. 1902].
[1906]. Oscillating paddle engines, sometimes made with cylinders at 90° apart and a single crank, as [No. 564].
[1907]. Overhead oscillating twin screw engines.
[1908]. Annular cylinder paddle engines.
[1909]. Overhead cylinder side-lever paddle engines.
In addition to the above some special types are occasionally employed, as the Willan’s three-cylinder plan for screw engines. See [No. 592], also varieties of [No. 593], high-speed types.