(a) Purpose. This section lists the requirements for spaces (other than propelling machinery spaces under § 69.121) which, though included in calculating gross register tonnage (i.e., are not exempt under § 69.117), are deducted from tonnage in deriving net register tonnage.

(b) General. (1) A deductible space must be used exclusively for, and be reasonable in size for, its intended purpose.

(2) When a space is larger than necessary for the safe and efficient operation of deductible equipment, only the space occupied by the equipment plus a two foot maximum working space on each side of the equipment, if available, is deductible.

(3) Space specified in this section may be located anywhere within the vessel, unless otherwise specified.

(c) Anchor gear. A space below the line of the uppermost complete deck occupied by the anchor gear, capstan, windlass, and chain locker is deductible. A fore peak used exclusively as chain locker is measured by the method prescribed under § 69.117(g)(3).

(d) Boatswain's stores. A space containing oils, blocks, hawsers, rigging, deck gear, or other boatswain's stores for daily use is deductible. The maximum deduction allowed for vessels less than 100 gross register tons is one ton and, for vessels 100 gross register tons or over, is one percent of the gross register tonnage, not to exceed 100 tons.

(e) Chart room. A space for keeping charts and nautical instruments and for plotting the vessel's course is deductible. For a combined wheelhouse and chart room, that part not exempted as wheelhouse under § 69.117(b)(9) is deductible. For small vessels in which the only space for a chart room is in a cabin or saloon, one half the space not to exceed 1.5 tons is deductible as chart room.

(f) Donkey engine and boiler. Donkey engine and boiler space is deductible when connected with the main (non-cargo) pumps of the vessel, except as follows:

(1) If the space is within the engine room or within the casing above the engine room and if the donkey engine is an auxiliary to the main propelling machinery, the space is an engine room deduction under § 69.121(b).

(2) If the space is above the line of the uppermost complete deck and if the donkey engine is not an auxiliary to the main propelling machinery, the space is exempt under § 69.117(b).

(g) Spaces for the exclusive use of officers or crew. (1) The following spaces, regardless of their location (unless otherwise noted), are deductible if not used by passengers:

(i) Sleeping rooms.

(ii) Bathrooms with a bath tub or shower but without a water closet.

(iii) Water closets below the line of the uppermost complete deck serving more than one person, with or without a bath tub or shower. Water closets, regardless of location, that serve only one person or that are accessible only through a stateroom or bedroom serving one person are considered as part of the space they serve and are deductible only if that space is deductible.

(iv) Clothes drying rooms.

(v) Drinking water filtration or distilling plant below the line of the uppermost complete deck.

(vi) Hospitals.

(vii) Mess rooms.

(viii) Office of the chief engineer.

(ix) Oil skin lockers.

(x) Pantries.

(xi) Recreation rooms.

(xii) Smoking rooms.

(xiii) Galleys below the line of the uppermost complete deck.

(2) Shops for engineers, carpenters, plumbers, or butchers and offices for clerks, pursers, or postmasters are not deductible, wherever located.

(h) Master's cabin. The master's sleeping room, dressing room, bathroom, observation room, reception room, sitting room, water closet, and office are deductible.

(i) Radio room. Spaces in which radio apparatus is installed and messages are sent and received and which may provide off-duty operator accommodations are deductible.

(j) Steering gear. Spaces for steering gear below the line of the uppermost complete deck are deductible.

(k) Generators. Spaces for generators below the line of the uppermost complete deck are deductible regardless of what space the generators serve. These spaces may include other equipment necessary for the generator's operation.

(l) Pump room. Spaces below the line of the uppermost complete deck containing pumps that are not capable of handling cargo and that are not fuel oil transfer pumps considered part of the propelling machinery under § 69.121(b)(2)(v) are deductible.

(m) Sail stowage. A space for stowing sails on a vessel propelled only by sails is deductible up to two and one-half percent of the vessel's gross register tonnage.

(n) Waste material space. (1) A tank or collection space, regardless of location, used for the carriage or collection of sewage, garbage, galley waste, trash, slop-oil mixture, tank cleaning residue, bilge residue, or other waste material generated aboard the vessel is deductible.

(2) Space below the line of the uppermost complete deck used exclusively to separate, clarify, purify, or otherwise process waste material generated aboard the vessel is deductible.

(o) Passageways. A passageway or companionway is deductible—

(1) If it serves deductible spaces only; or

(2) If it serves deductible spaces and is also the sole means of access to one of the following non-deductible spaces:

(i) Lockers of less than two tons each, containing medicine, linen, mops, or other items for the free use of the crew.

(ii) A ship's office.

(iii) Spare rooms (not exceeding two) used by a pilot, customs officer, reserve engineer, or employee or agent of the vessel's owner or operator.

(p) Markings for deductible spaces. (1) Each space deducted under this section must be marked with the words “Certified ______” (inserting the space designation, such as “Seaman”, “Generator”, Office of Chief Engineer”, “Hospital”, or “Anchor Gear”). If a deductible space berths more than one crew member, the marking must indicate the number of crew members berthed, such as “Certified ______ Seamen” (inserting the number of crew).

(2) The abbreviations “Cert.” for “certified” and “W.C.” for “water closet” may be used.

(3) The markings must be in Roman letters and Arabic numerals at least 1/2 inch in height, must be painted in a light color on a dark background, must be embossed, center-punched, carved, or permanently cut in a bulkhead or metal plate, and must be placed in a legible location over a doorway on the inside of the space. A metal plate, if used, must be permanently fastened in place by welding, riveting, lock screws, or a Coast Guard-approved bonding agent.

(q) Method for measuring deductible spaces. (1) A rectangular space must be measured by taking the product of its length, breadth, and height.

(2) A space with curved sides on or above the tonnage deck is measured according to § 69.109.

(3) Space less than 15 feet in length may be measured by any practical method.

(4) Spaces below the tonnage deck exceeding 15 feet in length and bounded by a curved surface conforming to the side of the vessel must be measured by the formula used for measuring the superstructure under § 69.113.

(5) The height of a space located on a platform in the hull must be measured from the top of the bottom hull frames, if the platform is used only to form a flat surface at the bottom of the space, if the platform is not more than one foot above the top of the bottom frames, and if the space below the platform is not usable.

(6) The height of a space is measured through any ceiling, paneling, false overhead, or other covering, to the space's structural boundary, unless the space enclosed by the covering is available for a non-deductible use.