Artikel 42

Should there be a break or breaks in the double bottom, the space below the tonnage deck is to be measured in parts. Each part is to be measured as if it were a separate ship of a tonnage length equal to the length of the part; and, therefore, the length of each part should be divided as stated in Article 21, with the exception that, if the length is not more than 30 feet or 9.14 metres, it is only divided into two.
Within the meaning of this article, the word “break” shall apply to cases (a) where there is an abrupt change in the depth of the double bottom, (b) where the double bottom continues at a lower level, and (c) where, at the end of a partial double bottom, the adjoining floors are of a depth different from that of the double bottom. The latter provision shall not apply to floors in peaks if such floors are deeper than the adjoining part of the double bottom (see Figures 57, 58 and 59).
At the ends and at the points of division of each portion, transverse sections are measured, the tonnage depth measured at the middle of the tonnage length of the ship being the factor which determines if the other tonnage depths are to be divided into four or six equal parts, in accordance with Article 32.
The area of each transverse section and the cubic capacity of each part of the space below the tonnage deck are to be calculated in accordance with the rules given in Articles 39, 40 and 41, and the sum of the different parts will constitute the under-deck tonnage of the ship.
Subject to the provisions of (c) in the second paragraph, the procedure set forth in the present article shall not apply in the case of a change in the depth of floors in a ship with single bottom or partial double bottom (see Figure 60).