[Illustration: AN ENGLISH RAILWAY FERRY BOAT.]
The illustrations above represent a double screw steam ferry boat for
transporting railway carriages, vehicles, and passengers, etc.,
designed and constructed by Messrs. Edwards and Symes, of Cubitt Town,
London. The hull is constructed of iron, and is of the following
dimensions: Length 60 ft.; beam 16 ft.; over sponsons 25 ft. The
vessel was fitted with a propeller, rudder, and steering gear at each
end, to enable it to run in either direction without having to turn
around. The boat was designed for the purpose of working the train
service across the bay of San Juan, in the island of Puerto Rico, and
for this purpose a single line of steel rails, of meter gauge, is laid
along the center of the deck, and also along the hinged platforms at
each end. In the engraving these platforms are shown, one hoisted up,
and the other lowered to the level of the deck. When the boat is at
one of the landing stages, the platform is lowered to the level of the
rails on the pier, and the carriages and trucks are run on to the deck
by means of the small hauling engine, which works an endless chain
running the whole length of the deck. The trucks, etc., being on
board, the platform is raised by means of two compact hand winches
worked by worm and worm-wheels in the positions shown; thus these two
platforms form the end bulwarks to the boat when crossing the bay. On
arriving at the opposite shore the operation is repeated, the other
platform is lowered, and the hauling engine runs the trucks, etc., on
to the shore. With a load of 25 tons the draught is 4 ft.
The seats shown on the deck are for the convenience of foot
passengers, and the whole of the deck is protected from the sun of
that tropical climate by a canvas awning. The steering of the vessel
is effected from the bridge at the center, which extends from side to
side of the vessel, and there are two steering wheels with independent
steering gear for each end, with locking gear for the forward rudder
when in motion. The man at the wheel communicates with the engineer by
means of a speaking tube at the wheel. There is a small deck house for
the use of deck stores, on one side of which is the entrance to the
engine room. The cross battens, shown between the rails, are for the
purpose of horse traffic, when horses are used for hauling the trucks,
or for ordinary carts or wagons. The plan below deck shows the
arrangement of the bulkheads, with a small windlass at each end for
lifting the anchors, and a small hatch at each side for entrance to
these compartments. The central compartment contains the machinery,
which consists of a pair of compound surface condensing engines, with
cylinders 11 in. and 20 in. in diameter; the shafting running the
whole length of the vessel, with a propeller at each end. Steam is
generated in a steel boiler of locomotive form, so arranged that the
funnel passes through the deck at the side of the vessel; and it is
designed for a working pressure of 100 lb. per square inch. This
boiler also supplies steam for the small hauling engine fixed on the
bulkhead. Light to this compartment is obtained by means of large side
scuttles along each side of the boat and glass deck lights, and the
iron grating at the entrance near the deck house. This boat was
constructed in six pieces for shipment, and the whole put together in
the builders' yard. The machinery was fixed, and the engine driven by
steam from its own boiler, then the whole was marked and taken
asunder, and shipped to the West Indies, where it was put together and
found to answer the purpose intended.--_Engineering._
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[For THE SCIENTIFIC AMERICAN.]