Page 257 - Rules of Navigation2020

Rule 2 for Laden Ships

(Art.9) When ships have their cargo on board, or when for any other reason their tonnage
cannot be ascertained by means of Rule 1, proceed in the following manner:

Measure the length on the upper deck from the outside of the outer plank at the stem
to the aft side of the stern-post, deducting there from the distance between the aft
side of the stern-post and the rabbet of the stern-post at the point where the counter-

plank crosses it.
Measure also the greatest breadth of the ship to the outside of the outer planking or

wales.
Then, having first marked on the outside of the ship, on both sides thereof, the height

of the upper deck at the ships sides, girth the ship at the greatest breadth in a
direction perpendicular to the keel from the height so marked on the outside of the

ship, on the one side, to the height so marked on the other side by passing a chain
under the keel; to half the girth thus taken add half the main breadth; square the
sum, multiply the result by the length of the ship taken as aforesaid; then multiply

this product by the factor 0.17 ( seventeen hundredths )in the case of ships built of
wood, and by the factor 0.18 ( eighteen hundredths ) in the case of ships built of

iron. The product will give approximately the cubical contents of the ship, and the
general tonnage can be ascertained by dividing by 100 or by 2.83, according to the
measurements taken in English feet or in meters.

(Art.10) If there is a break, a poop, or other permanent covered and closed -in spaces ( as

defined in the general principles ) on the upper deck, the tonnage of such spaces
shall be ascertained by multiplying together the mean length, breadth and depth of

such spaces and dividing the product by 100 or 2.83, according to the measurements
taken in English feet or meters, and the quotient so obtained shall be deemed to be

the tonnage of such space, and shall be added to the other tonnage in order to
determine the gross tonnage or total capacity of the ship.

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