the open face and the line drawn parallel to it shall be measured. The remainder of the space within a poop, forecastle, bridge house, or other superstructure or erection shall be considered as available for the accommodation of cargo or stores, of passengers or of the ship's personnel, and shall be measured and included in the gross tonnage. (See figs. 1, 2, and 3, following § 135.85.)

(1) Should the open space within a poop, forecastle, bridge house, superstructure, or erection between the end opening and a parallel line distant from the opening by half the breadth of the deck become, because of any arrangement, except by convergence of fore and aft bulkheads, of less width than half the breadth of the deck, then only the space between the line of the end opening and a parallel line drawn through the point where the athwartship width of the open space within the poop, forecastle, bridge house, superstructure, or erection becomes equal to, or less than, half the breadth of the deck shall be exempted from measurement. (See figs. 4, 5, 6, and 7 following § 135.85.) The remainder of the space within the poop, forecastle, bridge house, superstructure, or erection is to be included in the gross tonnage.

(2) When two erections extending from side to side of the ship are separated by an interval the fore-and-aft length of which is less than the least half breadth of the deck in way of such interval, then whatever be the breadth of the permanent end openings of the erections the entire erections, less the interval separating them, shall be measured and included in the gross tonnage. (See fig. 8 following § 135.85.)

(c) Certain space within a poop, forecastle bridge house or other "permanently covered and closed in" superstructure or erection. In a poop, forecastle, side-to-side bridge house, or other "permanently covered and closed-in" superstructure or side-toside erection the space directly in way of opposite openings, the height of which is at least 3 feet, in the side wall of the ship not provided with means of closing and corresponding to each other in the opposite walls of the ship

shall be exempted. (See figs. 9 and 10 following § 135.85.) Passages running fore-and-aft abreast the engine-room casing and open at both ends shall not be exempted. The deck erection including same shall be considered a side-to-side erection provided its outboard sides are flush with the hull of the vessel.

[31 FR 12328, Sept. 16, 1966, as amended at 41 FR 13582, Mar. 31. 1976]

§ 135.83 Certain spaces in way of opposite side openings and not provided with means of closing. *

Spaces in way of opposite side openings at least 3 feet in height not provided with means of closing shall be exempted. In the case of a continuous deck with one or more deck openings (usually designated as tonnage openings) that may be so closed as to permit cargo or stores to be carried in the space under the deck, or under portions thereof, only the spaces under such a deck that are exactly in way of opposite openings at least 3 feet in height in the side walls of the ship not provided with means of closing and corresponding to each other in the opposite walls of the ship shall be exempted; and the remaining spaces under such a deck shall be measured and included in gross tonnage. In case the openings in the side walls of the ship are provided with means of closing no portion of the space under such a deck shall be exempted. (See fig. 11 following § 135.85.)

[31 FR 12328, Sept. 16, 1966, as amended at 41 FR 13582, Mar. 31, 1976]

§ 135.84 Certain spaces framed in around funnels and spaces required for admission of light and air into engine rooms.

The spaces framed in around the funnels and the spaces required for the admission of light and air into the engine rooms shall be exempted from measurement to the extent that such spaces are above the deck or covering of the first or lowest tier of side-toside erections, if any, on the upper deck as defined in §§ 135.61-135.63. A deck with one or more deck openings (usually designated as tonnage openings) that may be so closed as to permit cargo or stores to be carried in

houses, in certain

§ 135.87 Companion cases.

Companion houses shall be exempted when used solely to protect stairways and ladders leading to spaces below. When used as smoking rooms or for any other purposes than companion houses, the parts so used shall be measured and included in gross tonnage.

§ 135.88 Domes, skylights, and airshafts.

Domes, skylights, and airshafts shall be exempt from measurement. When there is an opening in the floor of a superstructure immediately below a skylight, the exemption shall include the space between the skylight and the opening in the floor of the superstructure immediately under the skylight. The remainder of the superstructure shall be included in the measurement. The space, in addition to the skylight, that may be exempted by this section is that indicated by A, B, C, D in Figure 12, which follows.

Figure 12.—Open spaces between skylight and opening.

Spaces Available For Passengers Not To Be Exempted

§ 135.111 Spaces for use of passengers not exempted.

Spaces for the use or possible use of passengers shall not be exempted from measurement except as stated in § 135.82(a).

§ 135.112 "Passengers" defined in case of army and navy auxiliary ships.

In case of army and navy transports, colliers, supply ships, and hospital ships, as defined in §§ 135.1-135.3, the terms "passengers" shall include all officers, enlisted men, and other persons who are not assigned to duty and who are not duly inscribed on the ship's rolls.

System For Measurement Of Cubical Contents Of Spaces Included In Gross Tonnage

§ 135.141 Use of Moorsom system as applied in any country in measuring vessels for national registry.

The cubical contents of the spaces included, by this part, in gross tonnage may, in any country where the Moorsom system of measurement has been adopted, be ascertained under that system as applied in measuring vessels for national registry, provided that system is substantially similar to Moorsom system of measurement as set forth in §§ 135.142-135.241.

§ 135.142 Use of Moorsom system as set forth in this part.

In countries that have not adopted the Moorsom system of measuring spaces within vessels, the cubical contents of any of the spaces included in gross tonnage shall be ascertained according to the Moorsom system as set forth in the following sections; §§ 135.171-135.183 for the measurement of empty vessels; §§ 135.211135.213 for laden vessels; § 135.241 for open vessels.

[31 FR 12328, Sept. 16. 1966. as amended at 41 FR 13582, Mar. 31, 1976]

Rules For Measurement Of Gross
Tonnage Of Empty Vessels

§ 135.171 Length taken on tonnage deck.

The length for the admeasurement of ships having one or more decks is taken on the tonnage deck, which is:

(a) The upper deck for vessels having one or two decks.

(b) The second deck from below for vessels having more than two decks.

§ 135.172 Measurement of length, in general.

Measure the length of ship in a straight line along the upper side of the tonnage deck from the inside of the inner plank (average thickness) at the side of the stem to the inside of the midship stern timber or plank there, as the case may be (average thickness) deducting from this length what is due to the rake of the bow in the thickness of the deck and what is due to the rake of the stern timber in the thickness of the deck, and also what is due to the rake of the stern timber in one-third of the round of the beam; divide the length so taken into the number of equal parts required by the following table, according to the class in such table to which the ship belongs:

(a) Class 1. Ships of which the tonnage deck is, according to the above measurement, 50 feet long or under, into four equal parts.

(b) Class 2. Ships of which the tonnage deck is, according to the above measurement, above 50 feet long and not exceeding 120 feet, into six equal parts.

(c) Class 3. Ships of which the tonnage deck is according to the above measurement, above 120 feet long and not exceeding 180 feet, into eight equal parts.

(d) Class 4. Ships of which the tonnage deck is, according to the above measurement, above 180 feet long and not exceeding 225 feet, into 10 equal parts.

(e) Class 5. Ships of which the tonnage deck is, according to the above measurement, above 225 feet long, into 12 equal parts.

§ 135.173 Measurement of length in case of break in double bottom.

In the case of a break or breaks in a double bottom, the length of the vessel is to be taken in parts according to the number of breaks, and each part divided into a number of equal parts according to the class in the above table to which such length belongs.

§ 135.174 Finding of transverse area of ship at each point of division of length.

Then the hold being first sufficiently cleared to admit of the required depths and breadths being properly taken, find the transverse area of the ship at each point of division of the length or each point of division of the parts of the length, as the case may require as follows: Measure the depth at each point of division, from a point at a distance of one-third of the round of the beam below the tonnage deck, or, in the case of a break, below a line stretched in continuation thereof, to the upper side of the floor timber (upper side of the inner plating of the double bottom) at the inside of the limber strake, after deducting the average thickness of the ceiling which is between the bilge planks and the limber strake.

§ 135.175 Finding of transverse area of ship at each point of division of length; manner of taking depths in certain cases. In the case of a vessel constructed with longitudinal framing, the depths are to be taken to the upper edge or inner surface of the longitudinal frames, where no double bottoms exist. In the case of a ship constructed with a double bottom, the depth shall be taken to the upper side of the inner plating of the double bottom, and that upper side shall, for the purposes of measurement, be deemed to represent the floor timber of the vessel. This rule for measuring the depth of the hold applies to double-bottom ships having top of double bottom not horizontal. Subject to the provisions of § 135.85 regarding the exemption of double-bottom spaces, if any tank or compartment between the inner and outer plating of the double bottom is