240. REPORT—1858. 
remarkable ; and their attention being thus directed to a limited selection, 
embracing a considerable number of vessels of practically established excel- 
lence for sea service, the Committee hoped, after making due inquiry, to be 
enabled to present, as respects those vessels, a statistical exposition, in tabular 
form, of their various elements of construction and type of build, and thus, 
by a system of collation and induction, to discover practically those types 
and elements of construction which have been found by experience most con- 
ducive to good performances at sea. In the case of steam-ships, it was pur- 
posed that the statistics of the original trials to which steamers are generally 
put when new, should also be collected, classified, and collated with reference 
to the subsequent performances of the same vessels at sea, whence it might 
be determined to what extent and in what respects the usual smooth-water 
trials of steam-ships may be indicative of the probable properties to be ex- 
pected of the same ships at sea, as respects their dynamic capabilities. 
The Committee are happy to say that this attempt at practically inquiring 
into the peculiarities of construction to which the good or bad qualities of 
steam-ships may be attributable, has not been wholly fruitless; for, although 
shipowners, shipbuilders, and marine engine manufacturers have been 
generally reluctant to communicate particulars whereby the dynamic merits 
of ships may be numerically classed and compared, the results of which clas- 
sification and comparison might, if promulgated, affect the commercial value 
of their property and the relative professional reputation of constructors, 
still, in reply to the before-mentioned circular, information has been com- 
municated as to the performance of vessels, particularly steam-vessels, by 
which it appears that a great difference exists between steam-ships as respects 
their economic capabilities for the performance of mercantile steam transport 
service, leading to the conclusion that the general aggregate of steam service 
is performed by vessels of inferior adaptation for economic duty, and con- 
sequently at a rate of prime-cost expenditure ; and, therefore, ultimate charge 
on the public, greatly in excess of that which would be involved if all steamers 
were of the superior class of excellence that has been already in certain cases 
actually attained. For example, this Committee are assured, on authority 
which they believe to be unquestionable, that a certain vessel, the Bremen, 
of 3440 tons displacement at the time of trial, propelled by engines working 
up to 1624 indicated horse-power, attained the speed of 13°15 nautical miles 
per hour. Now, if we estimate the dynamic duty thus performed by the 
(13:15) (3440)2 _ 
1624 3 
2 
formula —=- =C, we shall have the coefficient, C= 
Ind.h.p. 
2274 X 227°88 
1624 
the mutual relation of displacement, speed, and power, appears, from the 
statements which have been communicated to this Committee, nearly 50 per 
cent. higher than that realized by the average performance of the steam-ships 
of the present day. The following are the coefficients of dynamic duty de- 
duced by the foregoing rule from the performances of mercantile steamers 
of high repute, of which the trial data have been communicated to this Com- 
mittee, viz. 325, 294, 291, 288, 259, 248, 231, 230, and 204, and many others 
below 200. 
This Committee therefore regard the Bremen as being a felicitous exem- 
plification of naval architecture as respects type of form adapted for easy 
propulsion ; and as we conceive that the promulgation of some of the con- 
structive elements of this vessel may be of public importance, we are happy 
in being authorized and enabled, by Messrs. Caird and Co., of Greenock, the 
constructors of the ship and of the engines, to communicate to the British 
= 319; and this coefficient of dynamic duty, resulting from 
