File:A manual of marine engineering- comprising the design, construction, and working of marine machinery (1907) (14766174232).jpg

Identifier: marineen00seatmanualofrich (find matches)
Title: A manual of marine engineering: comprising the design, construction, and working of marine machinery
Year: 1907 (1900s)
Authors: Seaton, Albert Edward, 1848-1930
Subjects: Marine engineering
Publisher: London, C. Griffin and company, limited New York, D. Van Nostrand co.
Contributing Library: University of California Libraries
Digitizing Sponsor: MSN

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e the bronze ones. The lignumvitse is sometimes fitted in strips, as in brass stern tubes, and sometimes intosquare holes, the bush being cast as a skeleton to hold the wooden blocks.This latter plan is very convenient for small ships, but not a good one forlarge ones, as the wood by the continued concussion gets impressed on thecast-iron tube. Lignum vita; weai-s best in end grain, especially when it isof inferior quality; when cut from a good tree of large size it wears equallywell either way. Lignum vitse and white metal strips should be from ;^-inch to ;-inch thick,and about three to four times their thicknesses in breadth; they must bebevelled so as to leave free watercourses between them. The brass behindthe strips should be 0-04 x diameter in thickness, and the metal ridgesbetween the wooden strips of the same thickness. Sometimes the brass bush * It is usual, however, to fit a separate bush containing the lignum vitae strips in allbut small ships for convenience of repair. 200
Text Appearing After Image:
o to THRUST. 201 is dispensed with, and the strips fitted into the cast-iron tube as in the brasstube, but this is not good practice. A pipe is fitted leading from the top of the stern tube to the bulkhead,through which the water may run from the tube so as to cause a fresh supplyto enter from the sea, and thereby prevent heating. From time to time attempts have been made to exclude sea water fromthe stern tube, and lubricate the shaft bearings with oil or soapy water.Ordinary stuffing-box, gland, &c., have been fitted to the tube end, and thelubricant fed through a pipe from the upper deck, so as to give a headsuperior to that of the sea water, and so prevent any leakage inward. Nogreat degree of success has followed this plan, as no provision is made for thewear of the bush. But if the bush did not wear the violent action of thescrew in a seaway would inevitably cause leakage. This difficulty has beengot over by Mr. Cedervall, who prevents water from entering by the meansshown i

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