Sivut kuvina
PDF
ePub

its disadvantage, although this is got over by casting it in two or more pieces, see Fig. 140, keying these together and riveting them through coupling flanges. When rudders are designed to be cast in one piece, the ribs which are cast on the blade to act as stays should be of easy section, so as not to interfere more than necessary with the contraction of the casting in cooling.

The oldest method of making the rudder for steel ships is the built type, Fig. 142, which consists of a forged frame having stock, stays, and back piece in one, with two side plates riveted to same

A

SECTION AT A. B.

FIG. 141.

FIG. 142.

FIG. 143.

after having the inside filled in with fir coated with tar. Its great objection is the cost of forging, especially for large rudders. It has gone completely out of favor unless for yachts, where its appearance commands its use, and in light craft of the torpedo boat kind where sufficient stiffness would not be obtainable in a single plate without going into a thickness which would make the weight prohibitive. It is also often used with the frame cast in gun metal and the side plates of 16 gauge brass sheet, for wood speed launches, vedettes, pinnaces, etc., although for these craft a cheaper and lighter rudder may be obtained by casting it complete in gun metal or bronze.

[graphic][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][merged small][subsumed][ocr errors][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed]
[graphic][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][ocr errors][merged small][subsumed][subsumed][merged small][merged small]
[graphic][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][ocr errors][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][ocr errors][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][merged small][merged small][subsumed]
[graphic][subsumed][subsumed][subsumed][subsumed][subsumed][merged small][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed]
« EdellinenJatka »