Bismarck daily tribune. [volume] (Bismarck, Dakota [N.D.]) 1881-1916, 1908-01-05
A VESSELS TONNAGE,
The Method of Figuring by Which.
1t Is AsCertained
STANDARD is FIXED BY Lev.

Our Government Recognizes Two
Kinds of Tonnage, Gross and Net
Displacement, the Scale by Which
Our Ships of War Are Described.
The vocabulary Of the sea, always
bewildering to landsmen. is crowded
full of strange, technical jargon and
of words of familiar meaning on shore
which afloat contract new and ar
bitrary significance. Take, for exam
pie, this matter of tonnage of ship
ping. On shore everybody knows that
a ton is 1000 pounds if short ton or
2,24O If long one. Therefore it seems
to the landlubber that 1000 ton ship
ought to be, if it is not, ship which
can carry thousand tons weight Of
cargo. AS a matter Of fact, a thou
sand ton ship can probably convey
about 1,30O or 1,4OO tons of coal or
heavy merchandise.
Yet the tonnage of shipping is not so
arbitrary as it seems. 1t follows q
law. There are two kinds Of ton
mage recognized by our government
uthorities-gross tonnage and net ton
mage. The gross tonnage Of vessel
Is its entire internal capacity measured
in tons of 100 cubic feet, and the navi-
cation laws Of the United States pre-
scribe in careful detail how this meas
urement for tonnage shall be ascer-
tanned. Net tonnage is measured by
subtracting from the gross tonnage Of
vessel all space used for the accom-
mediation of officers and crew, for GER
tain gear for the working of the ship
and, IT. a steam vessel, for her pro-
peliing power or machinery, including
boilers and engines.
In other words, the net tonnage of
ship is virtually the space, expressed
In tons Of 100 cubic feet, available for
the carrying Of passengers or cargo.
In the case Of sail vessels, from which
no machinery space has to be deduct
ed, the gross tonnage and net tonnage
OF vessel are very nearly the same.
But In steamers the two measurements
are widely different. Take, for exam
pie. Sae Of the largest Of American
merchant steamships, the American
liner st. Louis. Her gross tonnage Is
11,629. her net tonnage 1894. So with
the well known steamer Governor
Dingley Of the line from Boston to
Portland. Her gross tonnage Is 1896
her net 1856.
In all or nearly all Of the ports Of
the world ship taxes or dues are based
upon tonnage, In the United States
upon net tonnage. This is also the
standard Of tolls for the Suez canal.
As result the effort Of naval archi-
tects and shipbuilders and shipowners
generally is to keep the net tonnage Of
ship as small as possible. and many
ingenious devices for cheating meas
urement' have been adopted, design
ers of merchant vessels being as adept
In this art as designers Of racing
yachts. But the navigation laws Of
the United States are exceedingly vigil
liant on this point and are regarded as
fair and reasonable in their require
ments, SO that this evil of fraudulent
tonnage is believed to be less serious
under the flag the United States
than in the merchant navies Of some
other countries.
Landsmen may well be pardoned for
their perplexity that tonnage, in the
yernacular Of the sea, should mean
sometimes one thing and sometimes
another. The navy department adds
to the inevitable confusion by describ-
ing our ships Of war in terms not Of
gross register or net register, but Of
displacement. Thus the Massachusetts
Is spoken of officially as a battleship
Of 10000 tons and the Vermont as a
battleship Of 10000 tons. This means
in each case that the ship displaces SO
many tons Of water. But the Massa-
chusetts If measured as merchant ves-
sells are measured would have a net
tonnage Of only 1904 and would have
to pay dues on that only If passing
through the Suez canal. This practice
Of the navy department of using dis
placement tonnage instead of gross or
net tonnage gives the public an exag-
gerated idea of the actual size of our
ships of war. AS matter of fact, the
greatest battleships we have fall short
of the bulk Of the mightiest of our
merchantmen.
Again, another completely as to tom
mage arises in the cargo capacity of a
merchant ship. Take, for example,
typical Boston steam freighter, the
Lyra Of the Boston Towboat company.
Her gross tonnage is AIT; her net,
1916. But the Lyra has capacity Of
upward Of 5000 tons dead weight of
cargo
These national measurements Of
shipping, though apparently arbitrary,
are Indispensable, for ships cannot be
classified with any exactness on the
basis Of the tons of cargo they will
actually carry. A ship which could
receive and transport safely 5000 tons
Of weight Of pig iron would not hold
5000 tons Of hay or cotton. There
fore the governments Of the world
have had to prescribe measurement
standards of their own, in which the
great marine insurance companies
have had a powerful hand. And the
tendency Is to bring these standards