follows: Measure the internal mean length of the space in feet, and divide it into two equal parts; measure at the middle of its height three inside breadths, namely, one at each end and the other at the middle of the length; then to the sum of the end breadths add four times the middle breadth, and multiply the whole sum by one-third of the common interval between the breadths; the product will give the mean horizontal area of the space; then measure the mean height and multiply by it the mean horizontal area; divide the product by 100 (or by 2.83 if the measurements are taken in meters) and the quotient shall be deemed to be the tonnage of the space. § 135.182 Miscellaneous provisions as to measurement of length, breadth, and height. In measuring the length, breadth, and height of the general volume of the ship or that of the other spaces, reduce to the mean thickness the parts of the ceiling which exceed the mean thickness. When the ceiling is absent, or when it is not permanently fixed, the length and breadth shall be reckoned from the main frames of the ship, not from the web or belt frames. The same principle is to hold in the case of deck erections; that is, the breadth is to be reckoned from the main framing or stiffeners of the same, when ceiling is not fitted. When the main framing of the ship is curved or carried upward and inboard so as to permit the building of topside tanks or compartments outboard of the main framing, the breadth of the ship shall be reckoned from the outboard framing of such outboard tanks, thus including these tanks in the measurement. RULES FOR MEASUREMENT OF GROSS distance between the aft side of the sternpost and the rabbet of the sternpost at the point where the counterplank crosses it. Measure also the greatest breadth of the ship to the outside of the outer planking or wales at the middle perpendicular. Then, having first marked on the outside of the ship on both sides thereof the height of the uppermost full-length deck at the ship's sides, girt the ship at the middle perpendicular in a direction perpendicular to the keel from the height so marked on the oustide 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 in the case of ships built of wood, and by the factor 0.18 in the case of ships built of iron or steel. The product will give approximately the cubical contents of the ship, and the tonnage can be ascertained by dividing by 100 or by 2.83, according as the measurements are taken in English feet or in meters. § 135.213 Measurement of permanently covered or closed-in spaces on or above upper deck. If there is a break, a poop, or other permanently covered and closed-in spaces (as defined above in §§ 135.61135.63) on or above the uppermost fulllength deck, the tonnage of such spaces shall be ascertained by multiplying together the mean inside length, breadth, and depth of such spaces and dividing the product by 100, or 2.83, according as the measurements are taken in English feet or meters, and the quotient so obtained shall be deemed to be the tonnage of the spaces, and shall be added to the other tonnage, in order to determine the gross tonnage or total capacity of the ship. RULES FOR MEASUREMENT OF GROSS TONNAGE OF OPEN VESSELS § 135.241 Boundary line of measurement; depths how taken. In ascertaining the tonnage of open ships, the upper edge of the upper strake of the shell plating is to form the boundary line of measurement, and the depths shall be taken from an athwartship line, extended from upper edge to upper edge of the said starke at each division of the length. Subpart C-Deductions From Gross Tonnage To Ascertain Net Tonnage DEDUCTIONS ALLOWED FOR ALL VESSELS § 135.271 Deductions allowed for all vessels. The following spaces (enumerated in §§ 135.275-135.286) shall be deducted from the gross tonnage in order to ascertain the net tonnage of vessels not propelled by engines, and no other spaces shall be deducted. These deductions will also be allowed for vessels propelled by engines, with additional deductions for vessels propelled by engines, listed in §§ 135.321-135.327. Unless otherwise expressly stipulated, these spaces shall be deducted whether located above or below the upper deck. § 135.272 Measurement of cubical content of deducted spaces. The volume or cubical contents of deducted spaces shall be ascertained in the manner specified in §§ 135.141 or 135.142 or 135.142-135.241. The remainder, resulting from deducting from the total space included in gross tonnage the sum of the cubical contents of the spaces whose deduction from gross tonnage is permitted by this part, shall be the Panama Canal net tonnage of vessels upon which tolls and other charges based upon net tonnage shall be paid by vessels of commerce, army and navy transports, colliers, supply ships, and hospital ships (as defined in §§ 135.1-135.3) for passage through the Panama Canal. One hundred cubic feet, or 2.83 cubic meters, shall constitute one gross or net ton. § 135.273 Spaces for use of passengers, not deducted. Spaces for the use, or possible use, of passengers (as defined in §§ 135.111, 135.112) shall not be deducted from the gross tonnage, except in so far as their deduction may be specifically provided for in §§ 135.275-135.286. carried as freight on vessels of commerce, the following articles: (a) On transports, food, stores, luggage, accouterments, and equipment for passengers. (b) On colliers, coal, coaling gear, and fuel oil not for the use of the colliers. (c) On supply ships, stores, supplies of all kinds, distilling machinery and distilled water (other than fresh water stored in peak tanks for the vessel's own use), machines, tools and material for repair work, mines and mining materials, torpedoes, arms, and ammunition. (d) On hospital ships, food stores for passengers, medical stores, and hospital equipment. (e) Guns mounted on transports and supply ships, for defense of the ships, and ammunition required for use in such guns shall not be classed as cargo. § 135.275 Spaces for use of officers and crew, deducted. The tonnage of the spaces or compartments occupied by, or appropriated to the use of, the officers and crew of the vessel shall be deducted. The term "officers and crew" shall include the personnel inscribed on the ship's rolls, i.e., the ship's officers, engineers, doctors, apothecary, sick attendants, sailors, apprentices, firemen, mechanics, and wireless operators including clerks, pursers, stewards and other members of the personnel provided by the ship for the care of the passengers as well as armed guards on vessels of commerce. The spaces or compartments occupied by the officers and crew shall include their berthing accommodations, spaces provided for medical attention, including the medicine locker and dispensary, mess rooms, ward and dressing rooms, bath and washrooms, water closets, latrines, lavatories, or privies for their exclusive use, and passageways designed primarily for serving these spaces. Room provided for a pilot and so designated, shall be deducted, but spare rooms and linen lockers are not to be deducted. § 135.276 Certain spaces on hospital ships, deducted. On hospital ships the spaces or compartments occupied by doctors, apothecary, and sick attendants duly inscribed on the ship's rolls, shall form part of the deduction under § 135.275. Spaces provided for the medical attention of the officers and crew of a hospital ship shall likewise be deducted; but spaces fitted for the transportation, or for the medical attention, of other persons than those duly listed in the ship's rolls shall not be deducted. § 135.277 ducted. The spaces appropriated to the use of the master shall be deducted. Spaces for use of master, de § 135.278 Cook houses and other rooms when used exclusively to serve crew, deducted. Cook houses, galleys, bakeries, laundries, and rooms for ice machines, when used exclusively to serve the officers and crew, and the condenser space, and distilling rooms, when used exclusively for condensing and distilling the water for the officers and crew, shall be deducted. § 135.279 Spaces used for certain ship's gear and for operation and navigation, deducted. Spaces used for anchor gear, including the chain locker; steering gear, capstan; the wheel house; the dynamo; the chart room used exclusively for keeping charts, signals, and other instruments of navigation; offices for the master, chief officer, and chief engineer; lookout houses; spaces for keeping electric searchlights, radio appliances, and wireless telephone apparatus; carpenter shop; fumigating and fire-fighting machinery; and other spaces actually used in navigation of the ship, shall be deducted Such spaces upon vessels of commerce as may be devoted to the mounting of guns and to the storage of ammunition for the guns thus mounted shall be deducted. The deduction of all spaces, enumerated in this section, must be reasonable in extent and be subject to the limitations stipulated in § 135.287. § 135.280 Space used for storage of sails, deducted. In case of a ship propelled wholly by sails, any space, not exceeding 21⁄2 percent of the gross tonnage, used exclusively for storage of sails shall be deducted. 10 tons and in vessels from 150 to 500 tons at not more than 2 percent of the gross tonnage; in vessels under 150 tons at not more than 3 tons. § 135.282 Spaces used for engineer's shops, deducted. Spaces used exclusively for engineer's shops shall be deducted. This deduction is in no case to exceed 5 percent of the actual propelling machinery space nor be more than 50 tons for any vessel. § 135.283 Spaces used for donkey engine and boiler, and for pumps other than for handling cargo, deducted. The space occupied by donkey engine and boiler shall be deducted even through not connected with the main pumps of the ship. The space occupied by the pumps used exclusively for handling feed water, ballast, bunker fuel, or for freeing the ship of water shall also be deducted, but the space occupied by the pumps used for handling cargo shall not be deducted. § 135.284 Passageways designed for serving deducted spaces, deducted. Passages and passageways designed primarily for serving deducted spaces shall be deducted. § 135.285 Water ballast spaces, and peak tanks for fresh water for vessel's use, deducted. (a) Water ballast spaces, other than spaces in the vessel's double bottom, shall be deducted if they are adapted only for water ballast, have for entrance only ordinary circular or oval manholes whose greatest diameter does not exceed 30 inches, and are not available for the carriage of cargo, stores, or fuel. Peak tanks shall also be deducted when adapted only for carrying fresh water for the vessel's own use, can be entered only as above stated, and are not available for the carriage of cargo or fuel. If used to carry oil or other fuel these spaces shall be regarded as part of the vessel's fuel space and shall not be subject to separate deduction. (b) Tonnage of tanks may be obtained by using liquid capacity times the conversion factor with one-sixth off for frames in case of peak tanks and onetwelfth off in case of wings or deep tanks when they cannot be readily measured. § 135.286 Spaces appropriated to use of passengers as public rooms, deducted. Spaces appropriated to the use of the passengers solely as public rooms shall be deducted. These shall include such spaces as social halls, smoking rooms, music rooms, libraries, lounges, dining saloons, gymnasiums, children's playrooms, elevators, foyers, promenades, veranda cafes, barrooms, barber shops, novelty shops, and passageways designed primarily for serving such spaces. Waterclosets, toilets, lavatories and washrooms designed primarily to serve public spaces will be considered as part of the public spaces and be deducted accordingly. Waterclosets, toilets, lavatories, baths and washrooms designed primarily to serve nearby staterooms in the same tier will be considered as part of the staterooms they serve and not subject to deduction. § 135.287 Marking and use of deducted spaces. Each of the spaces enumerated in §§ 135.275-135.286, unless otherwise specifically stated, shall be subject to such conditions and requirements as to marking or designation and use or purpose as are contained in the navigation or registry laws of the several countries, but no space, other than fuel spaces deducted under §§ 135.351-135.354, shall be deducted unless the use to which it is to be exclusively devoted has been appropriately designated by official marking. In no case, however, shall an arbitrary maximum limit be fixed to the aggregate deduction made under §§ 135.271135.286. ADDITIONAL DEDUCTIONS ALLOWED FOR VESSELS PROPELLED BY ENGINES § 135.321 Determination of Panama Canal net tonnage of vessels propelled by engines. The Panama Canal net tonnage upon which tolls and other charges based upon tonnage shall be paid by vessels of commerce, army and navy transports, colliers, supply ships, and hospital ships, as defined in §§ 135.1-135.3, propelled by engines, for passage through the Panama Canal, shall be the tonnage remaining after the following deductions have been made from the gross tonnage. One hundred cubic feet, or 2.83 cubic meters, shall constitute one gross or net ton. Vessels propelled partly by sails and partly by engines shall be classed as "vessels propelled by engines." § 135.322 Spaces specified in §§ 135.271-135.286, deducted. The spaces specified in §§ 135.271– 135.286, shall be deducted from the space included in gross tonnage to ascertain net tonnage in the case of vessels propelled by engines as in the case of vessels not propelled by engines. § 135.323 Spaces occupied by engines, boilers, coal bunkers, etc., deducted. The space occupied by the engines, boilers, coal bunkers, fuel oil tanks, including settling tanks, lubricating oil tanks, and shaft trunks of vessels with screw propellers; spaces within a closedin side-to-side erection that are framed in around the funnels or that are required for the introduction of light and air to the engine room to the extent that the framed-in spaces around the funnels and the light and air casings are located below the deck or covering of the first or lowest tier of such erections, if any, on the upper deck, as defined in §§ 135.61135.63, and are contained in closed-in side-to-side erections; spaces necessary for the proper working of the engines, and spaces occupied by the donkey engine and boiler when situated within the boundary of the engine room or within the light and air casing above the engine room and when used in connection with the main machinery for propelling the vessel, shall be deducted. When the shaft of screw propellers pass through open spaces not inclosed within tunnels, the spaces allowed in lieu of the tunnels must be of reasonable dimensions suitable for the vessel in question. When any portion of the engine or boiler rooms is occupied by a tank for fresh water, the spaces thus taken up shall not be deducted. § 135.324 Donkey-engine and boiler spaces, when deducted. Donkey-engine and boiler spaces, when deducted according to §§ 135.381-135.383, shall not be made a separate deduction. § 135.325 Certain portion of framed-in spaces around funnels and light and air casings, exempted and not deducted. The portion of the framed-in spaces around the funnels and of the light and air casings that extend above the deck or covering of the first or lowest tier of side-to-side erections, if any, on the upper deck, as defined in § 135.84, and surrounding the said space or spaces are exempted from measurement and form no part of the space or spaces are exempted from measurement and form no part of the space deducted under §§ 135.323, 135.324. § 135.326 Limitation on propellingpower deductions; marking and use of deducted spaces. The deductions made for propelling power, including all those provided for in §§ 135.323-135.325, shall in no case exceed 50 percent of the gross tonnage. In other respects the spaces enumerated in said 135.323-135.325 shall, except as otherwise specifically stated be subject to the requirements as to designation or marking and use or purpose contained in the navigation or registry laws of the several countries. § 135.327 Propelling power deductions, how made. The deductions made for propelling power provided for in §§ 135.323-135.325 shall be made according to the provisions of §§ 135.351-135.353, as the owner of the vessel may elect. PROPELLING POWER DEDUCTION FOR VESSELS WITH BUNKERS HAVING MOVABLE PARTITIONS, OR HAVING FUEL-OIL COMPARTMENTS THAT MAY BE USED TO STOW CARGO OR STORES § 135.351 Space occupied by engine rooms plus percentage thereof, deducted. In ships that do not have fixed bunkers, but transverse bunkers with movable partitions, with or without lateral bunkers, and in ships with fuel tanks which may be used to stow cargo or stores, measure the space occupied by the engine rooms, and add to it for vessels with screw propellers 75 percent and for vessels with paddle wheels 50 percent of such space. § 135.352 What understood by space occupied by engine rooms. By the space occupied by the engine rooms is to be understood that occupied by the engine room itself and the boiler room, together with the spaces strictly required for the working of the engines and boilers, with the addition of the spaces taken up by the shaft trunks in vessels with screw propellers, the spaces which enclose the funnels and the casings necessary for the admission of light and air into the engine room to the extent that such spaces are located below the upper deck (as defined in §§ 135.61– 135.63) or below a deck with openings, usually designated as tonnage openings, which may be so closed as to permit the carriage of cargo or stores under the deck or a portion thereof, and donkeyengine and boiler spaces when the donkey engine and boiler are situated within the boundary of the main engine room, or of the light and air casing above it and when they are used in connection with the main machinery for propelling the vessel. When the shafts of screw propellers pass through open spaces not enclosed within tunnels, the spaces allowed in lieu of tunnels must be of reasonable dimensions suitable for the vessel in question. When a portion of the space within the boundary of the engine or labor rooms is occupied by a tank or tanks for the storage of fuel oil, lubricating oil, or fresh water, the space considered to be within the engine room shall be reduced by the space taken up by the tank or tanks for fuel oil, lubricating oil, or fresh water. Note that fuel-oil settling tanks are not to be included in the propelling-power space, no matter where situated. Storerooms, dynamos, ice machine, etc., situated in the confines of the engine room and not bulkheaded off, may be included in engine room space. If bulkheaded off, they shall not be included in engine room space but be given separate deductions when they qualify under §§ 135.271-135.286 and then listed under item 5 on page 2 of the Panama Canal certificate. § 135.353 Manner of ascertaining cubical content of spaces occupied by engine room. The cubical contents of the abovenamed spaces occupied by the engine room shall be ascertained in the following manner: Measure the mean depth of the space occupied by the engines and boilers from its crown to the ceiling at the limber strake; measure also three, or, if necessary more than three, breadths of the space at the middle of its depth, taking one of such measurements at each end and another at the middle of the length; take the mean of such breadths; measure also the mean length of the space between the foremost and aftermost bulkheads or limits of its length, excluding such parts, if any, as are not actually occupied by, or required for, the proper working of the engines and boilers. Multiply together these three dimensions of length, breadth, and depth, and the product will be the cubical contents of the space below the crown. Then, by multiplying together the length, |