Artikel 31

Should the tonnage deck be interrupted by a break and the deck continued at a higher or lower level, the depths of the transverse sections situated in way of the raised or sunken deck are to be measured to the under side of these decks. The depths thus obtained should then be decreased or increased, as the case may be, by the height of the break (see Figure 36).
If there exists below the tonnage deck a recessed portion entirely open to the sea, and therefore not liable to inclusion in the gross tonnage (e.g., the slipway in a whaling ship), such portion should be calculated separately and its cubic capacity excluded from the under-deck tonnage.