was found, owing possibly to the position of the screw, that the whole of
the plates immediately over the screws were damaged. Mr. Beckett Hill had
been using, during the past three or four years, the twin screw steamers
the Ludgate Hill, Richmond Hill, and Tower Hill. These were all over 4,000
tons register, and indicated, when at work at full speed, 2,500 h.p. Before
he and his friends built these steamers, they built some very large tug
boats on the twin screw principle. At the present moment, four of the
fastest steamers building for the Atlantic service were to have twin
screws. The great obstacle to the extension of the twin screw in the
mercantile navy had been the fear that the projection of these screws would
make the vessels very difficult to handle, but he had found no such
difficulties. He had found it an advantage to put the point of the
propeller as near the deadwood as he could, without actually touching it,
and in the large steamers, as well as in the tugs, the distance was a few
inches. As to the point of safety, he thought it a great advantage to have
twin screws, and on two occasions twin screw vessels had met with accidents
which, but for the twin screws, would have necessitated their putting back
to New York for repairs. The Richmond Hill, on one occasion, met with an
accident to her machinery two days after leaving New York; but she was able
to come on with the second set of engines, and was only one day late in the
passage. No difficulty had been found in the docking and undocking of these
vessels, either in London or Liverpool, and while with single screw vessels
they had sometimes to employ one or two dock boats to dock and undock them,
they never had to do so with the twin screw vessels. These vessels were 400
ft. long, with 48 ft. breadth of beam--a very large size to handle in a
river like the Thames. He noticed in the paper a propeller with a diameter
of 15 ft. 6 in. to indicate 11,110 h.p., so that a great Atlantic steamer,
which should indicate 11,000 or 12,000 h.p., and have a beam of about
65ft., would have her screws very well protected.