8. America. 5,528

Here the America shows to advantage, for while being eighth in size
she is fourth in point of speed, and from what the author can learn,
although he had no authenticated details on the subject, he believed
she is economical in coal consumption. He might perhaps be permitted
to say that one of the most difficult subjects in connection with the
propulsion of ships on which to get absolutely accurate data is that
of coal consumption. The records of six to eight hours' trials for the
purpose of ascertaining the coal consumption are absolutely worthless,
as all shipbuilders and engineers know, and so far as English ships
are concerned they are never attempted. Foreign owners frequently
stipulate for such trials in their contracts with English
shipbuilders, and get wonderfully economical results on paper, but the
fact that the trials only extend over a few hours renders them
valueless, however carefully the coal may be weighed during that
period. An authentic record of the absolute quantity of coal consumed,
say by each of the eight fastest Atlantic liners, together with their
average indicated horse power on the voyage, for a series of voyages,
would be extremely valuable.

He gave, in Table III., the consumption per indicated horse power per
hour for a number of ships. This table affords valuable data, for it
gives, in addition to the dimensions, the moulded draught of water,
the midship area, the displacement, the indicated horse power, the
speed on trial, the coefficients for the lines both from the block or
parallelopipedon, and also from the midship section prism, together
with the length and angle of entrance obtained by Kirk's rule, the
Admiralty displacement coefficient, together with the coal consumption
per day and per indicated horse power per hour.