Two centuries of shipbuilding by the Scotts at Greenock

Powerful Boiler- Making Tools. 115
need here be referred to. There is a 13-ft. gap hydraulic
plate-bending machine, which is entirely automatic in its
action, and can be set to any radius to bend plates up to
2 in. thick when cold. The flanging for the front and
back plates of boilers is done in an hydraulic machine,
exerting a pressure of over 160 tons. This machine has
four rams, two of which act downwards, one upwards, and
the other horizontally. It is served by a special hydraulic
jib-crane, capable of lifting the heaviest plates. There are
also plate-edge planers and triple boring mills of corre-
sponding power, while the vertical rolls take in plates up
to 10-ffc. wide.
For the riveting of the boilers there is a 13-ft. gap
hydraulic riveting machine, capable of exerting a load on
each rivet of 200 tons. The weight of this riveting
machine alone is about 60 tons, and it is served by an
independent hydraulic jib-crane. All the valves in con-
nection with the crane and riveter are led to a common
platform, so that one man is able to manipulate the whole
of the work.
There is also a large installation of special plant for
the manufacture of water-tube boilers, but it is scarcely
necessary to describe this in detail.
A large part of the boiler work, especially for warships,
is galvanised, and a special department has been organised
for this purpose. The tubes, in the first place, are thoroughly
cleaned, then placed in a zinc bath, and coated by electrolysis
to the desired extent ; the object being to expose defects, as
well as to protect the tubes from corrosion during manu-
facture. The amount of work done is, perhaps, the best
indication of the equipment of this department, as well as
of the water-tube department ; and this will be realised when
it is stated that over 24,000 tubes are required for the
boilers of one cruiser, and that six months suffices for their
construction.