86 REPORT—1857,. 
The war caused a great demand for screw steamers hired by the ton, and 
induced the numerous remeasurements under the new act; thus the anoma- 
lies of our tonnage laws are exemplified by there being three or four different 
measurements in use, all nearly equally indefinite as to the real bulk effi- 
ciency or tonnage capacity of vessels transferred. 
With respect to the fixing the load limit ;—at present we can obtain from 
the builder his construction load line and launching draught, and if in addi- 
tion we obtain the draught of water, the scale of displacement, and area of 
midship section, we have sufficient data for assigning a proper limit of 
loading, and marking it on the register as in Appendix B. 
Should the builder assign a load draft and displacement, such as nautical 
science may not justify, and as the safety limit must also depend much on 
the proportions and form of the vessel, the load draught of water and height 
of freeboard may be ascertained as follows:—For example, take one- 
twentieth of the length, one-fifth of the breadth, one-fifth of the depth, and 
divide by three—the result will be the safety freeboard measured from the 
deck or gunwale and the mean draft of load water, which should be men- 
tioned in the register and never exceeded. 
In conclusion, all that is requisite is, to alter the three clauses given in 
the present act of 1854, as it embodies the principles recommended by the 
Tonnage Committee of 1849 (and contained in the Bill of 1850), together 
with all the advantages derived from internal measurement, as given in the 
present act; and bases the register tonnage on the mean of the external 
bulk and internal space, thereby affording internal capacity and a displace- 
ment measurement, from which the weight of cargo carried could be as- 
certained. 
Alterations in the Clauses of the Merchant Shipping Act, 1854, appertaining 
to the Measurement of Ships for Tonnage, proposed by A. Henderson *. 
Clause 20. Throughout the following rules the tonnage deck shall be 
taken to the upper deck in ships which have less than three decks, and to 
be the second deck from below in all other ships; and in carrying such 
rules into effect all fractions of feet shall be expressed in decimals. “It 
being considered that the equitable basis on which charges for dock, light, 
harbour, and other dues should be made, is that of the entire cubical con- 
tents or external bulk to the medium height of the tonnage deck, together 
with the internal space or capacity under the tonnage deck (within the 
ceiling planking, exclusive of lower deck beams and fixtures of hull); the 
mean of the two being taken as the basis of registered tonnage. These 
quantities to be expressed in cubic feet and decimals on the register and 
certificate. ‘The difference between the external bulk and internal space to 
be considered the cubical contents of the hull of the vessel ; the per centage 
or ratio the cubic contents of the hull bear to that of the internal capacity, 
and of that quantity to the bulk, giving a fair criterion of the relative capa- 
city of timber and iron ships for light goods and passengers.” 
Clause 21. The tonnage of every ship to be registered, with the excep- 
tions mentioned in the next section, shall, previously to her being registered, 
be ascertained by the following rules hereinafter called Rule I. “ for External — 
Measurement and Internal Measurement ”; and the tonnage of every ship to 
which such rule can be applied, whether she is about to be registered or not, ~ 
shall be ascertained by the same rule. 
* The additions shown in italics or inverted commas. 
