20
3. The lines and triangle above mentioned shall be painted in white or yellow on a dark ground or in black on a light ground, and carefully cut in, centre punched or welded on the sides of the ship. They shall be so kept and maintained as to be plainly visible at all times have when submerged.
OPTIONAL TONAGE MARK FOR
FRESH' QA TROPICAL WATERS
↑ WCHES
1 INCH
FIGURE 1.
UNCH
INCHES
INCH
V
12 CHES
MCNES
1 INCHES
MORWARD
TONNAGE MARK
FIGURE 2.
THIS SKETCH ILLUSTRATES HOW THE EQUIVALENT SECOND DECK SHOULD BE DËTËRMINED, DASED
ON EQUAL LONGITUDINAL AREAS,
I
L1
+++
Ds - D+
*
21
FOURTH SCHEDULE
POSITION OP TONNAGE MARKS.
(regs. 13 & 14.]
1. The tonnage mark shall be placed on each side of the ship at a distance below the line where the underside of the second deck stringer plate meets the ship's side plating amidships, or below the line equivalent to that line as shown in Figure 2 in cases where the deck is stepped, to be ascertained by reference to the Tonnage Mark Table at the end of this Schedule.
In that Table--
(1) the length Lt in column A is the distance in test on the second deck between the points at the forward and after ends of the deck where the underside of the deck or line of continuation thereof meets the inner surface of the frames, ceiling or sparring as the case may be in the middle plane of the ship, using an equivalent length in cases where the deck is stepped as shown in Figure 2;
(2) the depth Ds is the depth in feet amidships from the top of the keel to the point at which the underside of the second deck stringer plate meets the ship's side plating, using an equivalent depib as shown in Figure 2 in cases where the deck is stepped:
(3) the figures at the top of columas B to J represent the ratio Lt/Di and the figures below in each column represent distances in inches from the line where the underside of the second deck stringer plate meets the ship's side plating amidships (or, in cases where the deck is stepped, from the equivalent line thereto as shown in Figure 2) to the point at which the upper edge of the tonnage mark is to be placed.
3. In the case of any ship of intermediale length or having ao inter- mediate L!/Da ratio, the relevant distance to be applied shall be obtained by interpolation, and in other cases where necessary by linear extrapolation.
4.
The effective relevant distance calculated by reference to the Ton- nage Mark Table to be applied in the case of any ship shall be corrected to the nearest half-inch.
3. In the case of a ship to which load lines have been assigned the tonmage marks shall, subject to the provisions of regulation 13 be placed in a position ascertained in accordance with the foregoing provisions of this Schedule with the apex of the identification triangle at a distance of 21 inches borizontally aft of the centre line of the load line disc:
Provided-
(1) that in cases in which a timber load line has been assigned to the
ship such distance shall be 42 inches,
(1) that in no case shall the tonnage marks be placed above the deepest load line to which the ship may be loaded, no account being taken for this purpose of timber load lines.
6. In the case of a ship to which load lines have not been assigned the tonnage marks shall be placed in a position ascertained in accordance with the foregoing provisions of this Schedule with the apex of the identi- Bcation triangle at the middle of the length Lt. In every such case the line of the upper deck shall be shown by a deck line corresponding in form to that required by the Load Line Rules and placed centrally to a vertical line bisecting the identification triangle of the tonnage mark.