The engineer's sketch-book of mechanical movements, devices, appliances, contrivances and details employed in the design and construction of machinery for every purpose

by Thomas Walter Barber

[362]. Ship’s Davit.

[363]. Balanced jib post crane, no tie rod. The weight must be sufficiently heavy to balance the jib and load.

[364]. Hydraulic strut jib crane. The load is raised by raising the jib.

[365]. Overside dock crane, for discharging from ships into barges. The overhang being very great in this design, it must be provided with a heavy frame or balance weight.

[366]. Wagon tip crane, for loading vessels.

[367]. Double sheave 4 to 1 purchase for crane jib. See also [Section 69].

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Section 19.—CONVEYING MESSAGES.

Messages can be conveyed by—

1.