118 REPORT—1857. 
With reference to the mutual relation of the load displacement and weight 
tonnage, it appears (see columns 29 and 82) that with the proportions of 
ship A, each 100 tons of load displacement will give 57 tons of weight 
tonnage, but with the proportions of ship M, each 100 tons of load displace- 
ment will give only 29 tons of weight tonnage ; that is, a ship of 1000 tons 
load displacement, on the type of ship A, will carry double the weight that 
would be carried by 1000 tons of displacement on the type of ship M. 
It might possibly be objected that the foregoing variations, which have all 
been calculated with reference to ships of 1000tons builders’ measure O.M.,are 
not applicable to vessels of a different magnitude; therefore, to test the validity 
or otherwise of this remark, the same constructive elements have been applied 
to a ship X of 20,939 tons builders’ measure O.M., and 25,000 tons load 
displacement, the length of this ship X being six times the beam, and the 
load-draught one-third of the beam, this type or proportion being the same 
as that of ship F. On comparison of the ships X and F (see columns 29, 
40, 31 and 32), it will be found that the ratios of builders’ tonnage, register 
tonnage, weight tonnage, and load displacement, are closely similar through- 
out: for example, in ship F, each 100 tons load displacement gives 42 tons 
of weight tonnage, but in ship X each 100 tons of load displacement gives 
89 tons of weight tonnage. Hence we may infer that the results of these 
calculations, showing the extent to which the weight-carrying capabilities of 
ships is irrespective of the nominal tonnage, whether it be builders’ tonnage 
O.M., or gross register tonnage N.M., and is approximately dependent on 
the constructor’s proportions of build, admit of general application to vessels 
of all sizes of the types referred to in Table A. Surely the above exposition 
is sufficient to establish the necessity of some legislative enactment under 
which builders’ tonnage O.M., and register tonnage N.M., should not be 
permitted to co-exist as recognized measurements of the mercantile capa- 
bilities of shipping. Under existing circumstances, it is respectfully sub- 
mitted for the consideration of the British Association, that a clause be in- 
troduced into the Merchant Shipping Act, that the only legal signification 
of the word “tonnage” shall be the measurement prescribed by the said Act, 
and that no other signification of that term shall be legally binding in com- 
mercial transactions. Also, that the capability of ships for carrying weight, 
as measured with reference to some determinate freeboard, be made an item 
of registration. j 
The ratios above set forth, as expressing the weight-carrying capability 
of ships, include the whole weight available for engines, boilers, coal, con- 
sumable stores, and cargo; so that, as applied to steam-ships, these ratios, as 
respects weight-tonnage for cargo chargeable for freight, assume a new phase 
of great importance as affecting mercantile steam transport economy; and, 
for the purpose of inquiring into the modification thus introduced, the fol- 
lowing Table B has been calculated, showing the mutual relations of dis- 
placement, power, and speed, for vessels up to 25,000 tons load displacement, 
the speed varying from 6 knots up to 25 knots per hour. 
The element “Load Displacement” being common to both Tables A 
and B, we have, by the aid of these Tables combined, the means of showing 
the mutual relations between builders’ tonnage O.M., gross register tonnage 
N.M., weight-tonnage, load displacement, speed, and power of all vessels 
within the limits of the types or proportions of build referred to in Table A, 
and thus showing to what an extent mercantile transport economy by steam 
is affected by the proportions of length, breadth, and depth to which steam- 
ships may be built. For example: let us compare a ship of the type D, 
namely, length six times the beam, and load-draught two-thirds the beam, 
a ae nn ae | 
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