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(i) Parts 20 feet or under in length are divided into two equal parts.
(ii) Parts over 20 feet and under 40 feet in length are divided into four equal parts.
(iii) Parts 40 feet or over are divided as provided in paragraph (g)(1) of this section.
(2) The tonnage of each part is calculated separately. The sum of the tonnages of the parts is the under-deck tonnage.
(n) Outside shaft tunnel exclusion. Any portion of an outside shaft tunnel included in tonnage through the process of measurement is subtracted from the under-deck tonnage.
(o) Open vessels. (1) An open vessel is one of any length without a deck or with one or more partial decks, the total length of which is less than one-half the tonnage length.
(2) The line of the tonnage deck for an open vessel is the upper edge of the upper strake. Depths of transverse sections are taken from this line.
(3) Any vessel, other than one having a mechanically refrigerated hold, that is not an open vessel and that has a tonnage length of less than 50 feet is measured as an open vessel, if the distance between the line of its tonnage deck and the upper edge of the upper strake is more than one-sixth of the midship depth. “Midship depth” means the depth measured from the line of the upper edge of the upper strake to the point in the bottom used for measuring tonnage depths.
[CGD 87–015b, 54 FR 37657, Sept. 12, 1989; 54 FR 40240, Sept. 29, 1989]
§ 69.111 Between-deck tonnage.
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(a) Defined. “Between-deck tonnage” means the tonnage of the space above the line of the tonnage deck and below the line of the uppermost complete deck.
(b) Identifying the line of the uppermost complete deck. (1) If the uppermost complete deck runs in a continuous line from stem to stern, the line of the uppermost complete deck is the longitudinal line of the underside of the uppermost complete deck.
(2) If the uppermost complete deck runs at different levels from stem to stern, the line of the uppermost complete deck is the longitudinal line of the underside of the lowest portion of that deck parallel with the upper portions of that deck. Spaces between the line of the uppermost complete deck and the higher portions of the deck are included in superstructure tonnage.
(c) Method for calculating tonnage. The tonnage of each level of the between-deck space is calculated separately, as follows:
(1) The length of each level is measured at the mid-height between the line of the deck above and the line of the deck below. Measure from the point forward where the continuation of the line of the inboard face of the normal side frames intersects the center line of the vessel aft to the forward face of the normal transom framing.
(2) Divide the length under paragraph (c)(1) of this section into the same number of equal parts into which the tonnage length is divided under §69.109(g)(1).
(3) Measure at mid-height between the faces of the normal side frames the inside breadth of the space at each end and at each point of division of the length. Number the breadths successively “1”, “2”, and so forth beginning at the bow.
(4) Multiply the even numbered breadths by four and the odd numbered breadths by two, except the first and last, which are multiplied by one.
(5) Add together the products under paragraph (c)(4) of this section and multiply the sum by one-third of the interval between the points at which the breadths are taken. The product is the square foot area of the space at mid-height.
(6) Multiply the area of the space at mid-height by the average of the heights taken each point of division of the space. The product divided by 100 is the tonnage of that space.
(7) The between-deck tonnage is the sum of the tonnage of each level within the between-deck space.
[CGD 87–015b, 54 FR 37657, Sept. 12, 1989, as amended by CGD 97–057, 62 FR 51045, Sept. 30, 1997]
§ 69.113 Superstructure tonnage.
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(a) Defined. “Superstructure tonnage” means the tonnage of all permanent structures, such as forecastle, bridge, poop, deckhouse, and break, on or above the line of the uppermost complete deck (or line of shelter deck, if applicable).
(b) Method of calculating tonnage. The tonnage of all structures on each level on or above the uppermost complete deck (or shelter deck, if applicable) is calculated separately as follows:
(1) The length of each structure is measured along its centerline at mid-height between the line of the inboard face of the framing on one end to the line of the inboard face of the framing on the other end. (See §69.123, figure 11.)
(2) Divide the length under paragaph (b)(1) of this section into an even number of equal parts most nearly equal to those into which the tonnage length is divided under §69.109.
(3) Measure at mid-height the inside breadth at each end and at each point of division of the length. Number the breadths successively “1”, “2”, and so forth, beginning at the extreme forward end of the structure. If an end of the structure is in the form of a continuous arc or curve, the breadth at that end is one-half the nearest breadth. If an end is in the form of an arc or curve having a decided flat, the breadth at the end is two-thirds of the nearest breadth.
(4) Multiply the even numbered breadths by four and the odd numbered by two, except the first and last breadth, which are multiplied by one.
(5) Add together the products under paragraph (b)(4) of this section and multiply the sum by one-third of the interval between the points at which the breadths are taken. The product is the square foot area of the structure at mid-height.
(6) Multiply this area by the average of the heights taken at each point of division of the structure between its decks or the line of its decks. The product divided by 100 is the tonnage of that structure.
(c) A structure having steps in its deck or side must be measured in parts.
(d) The superstructure tonnage is the sum of tonnages of each level above the line of the uppermost complete deck (or shelter deck, if applicable).
(e) When a structure is located over a cut-away portion of the tonnage deck, the structure's height is measured from the under side of its overhead deck to the line of the tonnage deck. If the tonnage deck has no camber, allow for camber in the overhead deck.
(f) For structures of a standard geometric shape, a simple geometric formula that yields an accurate volume may be used.
§ 69.115 Excess hatchway tonnage.
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(a) Hatchways that are above the tonnage deck and are either open to the weather or within open structures are measured to determine excess hatchway tonnage. Hatchways that are in between-deck spaces, on decks within closed-in structures, or on open structures are not measured.
(b) The tonnage of a hatchway is its length times breadth times mean depth divided by 100. Mean depth is measured from the under side of the hatch cover to the top of the deck beam.
(c) From the sum of the tonnage of the hatchways under this section, subtract one-half of one percent of the vessel's gross tonnage exclusive of the hatchway tonnage. The remainder is added as excess hatchway tonnage in calculating gross tonnage.
§ 69.117 Spaces exempt from inclusion in gross tonnage.
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(a) Purpose. This section lists spaces which are exempt from inclusion in gross tonnage.
(b) Spaces on or above the line of the uppermost complete deck. The following spaces or portions of spaces on or above the line of the uppermost complete deck are exempt if the spaces or portions are reasonable in extent and adapted and used exclusively for the purpose indicated:
(1) Spaces for anchor gear, including capstan, windlass, and chain locker, are exempt.
(2) Companions and booby-hatches protecting stairways or ladderways leading to spaces below are exempt, whether or not the spaces below are exempt.
(3) Galley or other spaces fitted with a range or oven for cooking food to be consumed on board the vessel are exempt.
(4) Spaces designed to provide light or air to propelling machinery are exempt, as follows:
(i) When propelling machinery is located entirely on or above the line of the uppermost complete deck, the entire propelling machinery space and all fuel bunker spaces that are also located above that line are exempt as light or air spaces. (See exception in §69.121(d)(1) for framed-in spaces.)
(ii) When part of the propelling machinery projects above the line of the uppermost complete deck into a space used exclusively to provide light or air to the propelling machinery, the entire space is exempt as light or air space. When any portion of this space is used for purposes other than providing light or air, only the portion of the space used for light or air, the space occupied by the propelling machinery itself, and a propelling machinery working space allowance under §69.121 limited to two feet, if available, on each side of the propelling machinery are exempt.
(iii) Any part of an escape shaft, or a companion sheltering an escape shaft, above the line of the uppermost complete deck is exempt as light or air space.
(iv) Space that would otherwise be exempt as a light or air space is not exempt when propelling machinery is boxed-in and does not extend above the line of the uppermost complete deck. Any portion of the boxed-in space above the line of the uppermost complete deck is exempt.
(5) Skylights affording light or air to a space below, other than to propelling machinery spaces. Space immediately below the line of the deck on which a skylight is located is exempt only when there is an opening in the next lower deck directly below the skylight to permit light or air to an even lower deck.
(6) Machinery spaces, other than for propelling machinery under §169.121.
(7) Spaces for steering gear.
(8) Water closet spaces that are fitted with at least a toilet and are intended for use by more than one person.
(9) The space in a wheelhouse necessary for controlling the vessel.
(c) Passenger spaces. (1) As used in this section, the term “passenger” includes officers and enlisted men on military vessels who are not assigned ship's duties and not entered on the ship's articles.
(2) As used in this section, “passenger space” means a space reserved exclusively for the use of passengers and includes, but is not limited to, berthing areas, staterooms, bathrooms, toilets, libraries, writing rooms, lounges, dining rooms, saloons, smoking rooms, and recreational rooms. The space need not be part of or adjacent to a berthing area to be considered a passenger space.
(3) A passenger space located on or above the first deck above the uppermost complete deck is exempt from gross tonnage.
(4) A passenger space located on the uppermost complete deck is exempt from gross tonnage only when it has no berthing accommodations and is an open structure under paragraph (d) of this section.
(d) Open structures. (1) Structures that are located on or above the line of the uppermost complete deck that are under cover (sheltered) but open to the weather are exempt from gross tonnage.
(2) A structure is considered “open to the weather” under paragraph (d)(1) of this section when an exterior end bulkhead of the structure is open and, except as provided in paragraphs (d)(4), (d)(5), and (d)(6) of this section, is not fitted with any means of closing. To be considered “open to the weather”, the end bulkhead must not have a coaming height of more than two feet in way of any required opening and have one of the following:
(i) Two openings, each at least three feet wide and at least four feet high in the clear, one on each side of the centerline of the structure.
(ii) One opening at least four feet wide and at least five feet high in the clear.
(iii) One opening at least 20 square feet in the clear with a breadth in excess of four feet and a height of not less than three feet.
(3) A compartment within an open structure is considered open to the weather only when an interior bulkhead of that compartment has an opening or openings that meet the requirements for end bulkheads under paragraphs (d)(2)(i) through (d)(2)(iii) of this section. Other compartments within the structure are not considered open to the weather.
(4) An interior or exterior opening that is temporarily closed by shifting boards dropped into channel sections at the sides of the opening is considered open to the weather if battening, caulking, or gaskets of any material are not used.
(5) An interior or exterior opening that is temporarily closed by cover plates or boards held in place only by hook bolts (see §69.123, Figure 12) is considered open to the weather—
(i) If hook bolts used to secure cover plates or boards are spaced at least one foot apart and hook over a stiffener installed around the perimeter of the opening;
(ii) If the cover plates or boards fit tightly against the bulkhead; and
(iii) If battening, caulking, or gaskets of any material are not used.
(6) An interior or exterior opening that is temporarily closed by cover plates or boards held in place only by bolts and crosspieces is considered open to the weather—
(i) If the bolts are not installed through the bulkhead;
(ii) If the bolts and crosspieces are not held in place by cleats or other attachments to or through the bulkhead;
(iii) If the cover plates or boards fit tightly against the bulkhead; and
(iv) If battening, caulking, or gaskets of any material are not used.
(7) A structure with its aft end entirely open from the under side of its overhead stiffeners down to the deck, to the line of the deck, or to a coaming not exceeding three inches in height and open athwartship between the inboard faces of the side stiffeners is considered open to the weather. The opening may be covered by a wire mesh screen or temporarily closed by canvas secured at the top and lashed or buttoned in place.
(e) Open space between the shelter deck and the next lower deck. (1) Space that is between the shelter deck and the next lower deck and that is under cover (sheltered) but open to the weather is exempt from gross tonnage when all openings in the uppermost complete deck are provided with a watertight means of closing.
(2) A space is considered “open to the weather” under paragraph (e)(1) of this section when the shelter deck above the space has a middle line opening which conforms to the following:
(i) The middle line opening must be at least four feet long in the clear and at least as wide as the after cargo hatch on the shelter deck, but not less than one-half the width of the vessel at the midpoint of the length of the opening. The opening may have rounded corners not exceeding a nine inch radius. When a greater radius is required by the Coast Guard or a Coast Guard recognized classification society under §42.05–60 of this chapter, notification of that requirement must be submitted to the Commandant.
(ii) The middle line opening must be located so that the distance between the aft edge of the middle line opening and the vessel's stern is not less than one-twentieth of the tonnage length of the vessel and the distance between the fore edge of the opening and the vessel's stem is not less than one-fifth of the tonnage length of the vessel.
(iii) The middle line opening must not be within a structure of any type.
(iv) If the middle line opening is guarded by rails or stanchions, the rails and stanchions must not be used to secure or assist in securing a cover over the opening.
(v) The coaming of the middle line opening must not exceed one foot mean height above the shelter deck. Bolts must not pass through the stiffeners or flanges on the coaming, nor may there be any other attachments on the coaming for fastening a cover. Portable wood covers may be fitted over the middle line opening if held in place only by lashings fitted to the under side of the covers. Metal covers may be fitted if held in place only by hook bolts spaced not less than 18 inches apart that pass through the cover and hook over angle stiffeners or flanges fitted to the outside of the coaming.
(vi) The space below the middle line opening must have a minimum length of four feet throughout its entire breadth and height and be in the clear at all times.
(vii) A scupper having a five inch minimum inside diameter and fitted with a screw down non-return valve geared to and operated from the shelter deck must be fitted on each side of the upper deck in way of the middle line opening.
(3) When the shelter deck space forward or aft of the middle line opening is divided by interior bulkheads, only those compartments with at least two openings that progress to the middle line opening are considered “open to the weather” under paragraph (e)(1) of this section. Each required opening must be at least three feet wide and at least four feet high in the clear, must not have a coaming height of more than two feet, and must not be fitted (except as provided in paragraphs (d)(4), (d)(5), and (d)(6) of this section) with any means of closing. Other compartments within the shelter deck space are not considered “open to the weather” under paragraph (e)(1) of this section.
(f) Water ballast spaces. A space, regardless of location, adapted only for water ballast and not available for stores, supplies, fuel, or cargo (other than water to be used for underwater drilling, mining, and related purposes, including production), upon request, may be exempt from gross tonnage if the following are met:
(1) The space must be available at all times only for water ballast that is piped through a system independent of other systems (except fire fighting and bilge suction systems). Pumps, pipes, and other equipment for loading and unloading water ballast must be of a size suitable for the efficient handling of the water ballast within a reasonable time frame. All manholes providing access to a water ballast space must be oval or circular and not greater than 34 inches in diameter. Except for those on a deck exposed to the weather, the manholes may have a coaming not exceeding six inches in height. Existing hatches over spaces being converted to water ballast spaces must have a watertight cover plate welded to the hatch and a manhole, as described in this paragraph, fitted in the plating.
(2) The primary purpose of the water ballast must be to afford a means of maintaining the vessel's stability, immersion, trim, pre-loading conditions, or seakeeping capabilities.
(3) If the space is in a vessel that is subject to inspection under 46 U.S.C. 3301, the space must be considered when determining the adequacy of the vessel's stability under 46 CFR chapter I.
(4) If the total of all water ballast spaces to be exempted from gross tonnage exceeds 30 percent of the vessel's gross tonnage (as calculated under this subpart without any allowance for water ballast), a justification of the operating conditions that require the water ballast must be submitted to the measuring organization for approval. Although a single condition may justify all water ballast spaces, several conditions may be necessary in other cases. However, a particular tank is not justified by a condition if another tank already justified by another condition could be used as effectively. The justification must—
(i) Designate the vessel's service;
(ii) Explain for what purpose under paragraph (f)(2) of this section the water ballast is being used;
(iii) Provide the calculations required in paragraphs (f)(4)(vi) through (f)(4)(ix) of this section for those uses on a form similar to Coast Guard Stability Test Form CG–993–9;
(iv) Include the capacity, tank arrangement, and piping plans for the vessel;
(v) Include a statement certifying that the space will be used exclusively for water ballast as prescribed by this section;
(vi) If water ballast is used for stability, describe each loading condition and the resultant metacentric height (GM) and include calculations;
(vii) If water ballast is used for immersion or trim, describe those conditions and include loading and trim calculations;
(viii) If water ballast is used for pre-loading, describe how it is used and include strength and weight calculations; and
(ix) If water ballast is used for seakeeping, describe each loading condition, GM, period of roll, and, if speed is involved, speed versus trim and draft and include calculations.
(5) If the water ballast space or its use, purpose, or piping are changed, the vessel owner or operator must report the change promptly to a measurement organization listed in §69.15 for a determination as to whether a tonnage remeasurement is required.
(g) Methods for measuring exempt spaces. (1) If the exempt space is located within the superstructure, the exempt space is measured using the same procedures used to measure superstructure tonnage under §69.113.
(2) If the exempt space is located between-deck, the space is measured using the same procedures used for between-deck tonnage under §69.111(c), except that the length of the exempt space is divided into the even number of spaces most equal to the number of spaces into which the between-deck was divided.
(3) If the exempt space is located under-deck, the space is measured using the same procedures used for under-deck tonnage under §69.109, except that the length of the exempt space is divided into the even number of spaces most equal to the number of spaces into which the under-deck was divided.
[CGD 87–015b, 54 FR 37657, Sept. 12, 1989; 54 FR 40240, Sept. 29, 1989; CGD 97–057, 62 FR 51045, Sept. 30, 1997; CGD 95–028, 62 FR 51203, Sept. 30, 1997; USCG–1999–5118, 64 FR 47404, Aug. 31, 1999]
§ 69.119 Spaces deducted from gross tonnage.
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(a) Purpose. This section lists the requirements for spaces (other than propelling machinery spaces under §69.121) which, though included in calculating gross tonnage (i.e., are not exempt under §69.117), are deducted from gross tonnage in deriving net 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 tons is one ton and, for vessels 100 gross tons or over, is one percent of the gross 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 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.
[CGD 87–015b, 54 FR 37657, Sept. 12, 1989; 54 FR 40240, Sept. 29, 1989; CGD 92–058, 57 FR 59938, Dec. 17, 1992]
§ 69.121 Engine room deduction.
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(a) General. The engine room deduction is either a percentage of the vessel's total propelling machinery spaces or a percentage of the vessel's gross tonnage.
(b) Propelling machinery spaces. (1) Propelling machinery spaces are the spaces occupied by the main propelling machinery and auxiliary machinery and spaces reasonably necessary for the operation and maintenance of the machinery. Propelling machinery spaces do not include spaces for fuel tanks, spaces exempt from gross tonnage under §69.117, and spaces not used or not available for use in connection with the propelling machinery.
(2) Propelling machinery spaces are—
(i) Space below the crown. The crown is the top of the main space of the engine room to which the heights of the main space are taken. The crown is either the underside of a deck or, if the side bulkheads are sloping, the uppermost point at which the slope terminates. (See §69.123, figures 13 and 14.)
(ii) Framed-in space located between the crown and the uppermost complete deck and used for propelling machinery or for the admission of light or air to propelling machinery spaces. (See §69.123, figures 13 and 14.)
(iii) Shaft tunnel space and thrust block recess space.
(iv) Space below the uppermost complete deck used for escape shafts or trunked ladderways leading from the aft end of the shaft tunnel to the deck above.
(v) Space containing a fuel oil transfer pump located in a separate space and not used for bunkering the vessel. When the pump serves both ballast and fuel oil, only one-half of the pump's space is considered a propelling machinery space.
(vi) Spaces containing fuel oil settling tanks used solely for the main boilers. The space must not exceed one percent of the vessel's gross tonnage.
(vii) Spaces for engineers' stores and workshops located below the uppermost complete deck and either open to a propelling machinery space or separated from a propelling machinery space only by a screen bulkhead. The space must not exceed three-quarters of one percent of the vessel's gross tonnage.
(viii) Framed-in space located above the line of the uppermost complete deck and used for propelling machinery or for the admission of light or air to a propelling machinery space, when requested under paragraph (d) of this section.
(ix) If the propelling machinery is boxed-in below the tonnage deck, the boxed-in space plus the spaces outside of the boxing for the shaft, auxiliary engines, and related propelling machinery. If a portion of the boxed-in space extends above a platform or partial deck that is below the uppermost complete deck, that portion is also considered part of the propelling machinery space.
(c) Methods for measuring propelling machinery spaces. (1) If the propelling machinery space is bulkheaded off or is not larger than necessary for the safe operation and maintenance of the propelling machinery, the entire space, or, if bulkheaded off, the portion bulkheaded off, is measured for the engine room deduction.
(2) If the propelling machinery space is not bulkheaded off or is larger than necessary for the safe operation and maintenance of the propelling machinery, only the space occupied by the propelling machinery itself plus a working space of two feet, if available, on each side of the propelling machinery is measured for the engine room deduction. If the working space overlaps another working space not related to the propelling machinery, only one-half of the overlapping working space is included in the propelling machinery space. The height of the working space is measured as provided in paragraph (c) of this section.
(3) If the propelling machinery is located in more than one space, each space must be measured separately.
(4) If the propelling machinery is located in a space with a step in the bottom or side lines, each stepped portion of the space must be measured separately.
(5) The length of a space under paragraph (c)(1) of this section is measured from the bulkhead just forward of the propelling machinery to the bulkhead just aft of the propelling machinery. The length of a space under paragraph (c)(2) of this section is measured from the forward edge of the working space to the aft edge of the working space.
(6) If the boundaries of the propelling machinery space form a rectangle, the product of the length, breadth, and height, divided by 100, is the tonnage of the space.
(7) If the boundaries of the propelling machinery space are continuous fair lines, heights are measured at the fore and aft ends and at the center of the space from the bottom frames, floors, or tank top of a double bottom up to the line of the crown. A breadth is measured at half-height of each height. The product of the length, mean breadth, and mean height, divided by 100, is the tonnage of the space.
(8) If the propelling machinery space is in the aft end of the hull, extends from side to side of the hull, and has a continuous bottom line, the length of the space is divided into the even number of equal parts most nearly equal to the number of parts that the tonnage length under §69.109(g) was divided. The tonnage is then calculated by the same method used for calculating the under-deck tonnage in §69.109(l).
(9) The tonnage of a framed-in space located between the crown and the uppermost complete deck and used for propelling machinery or for the admission of light or air to the propelling machinery space, is the product of its length, breadth, and height, divided by 100.
(10) The tonnage of a shaft tunnel, or a thrust block recess, having a flat top is the product of its length, breadth, and height, divided by 100. If the shaft tunnel or thrust block recess top is not flat, the space above must be calculated by using the appropriate geometrical formula. If the space aft of the shaft tunnel extends from side to side of the vessel, the tonnage of the space is found by the formula for measuring peak tanks in §69.109(l).
(11) The length and breadth of the space for a shaft tunnel, or a thrust block recess, when not cased is that which is necessary for maintenance of the shaft. The height allowed for thrust block recess space must not exceed seven feet. The mean height allowed for the shaft tunnel space must not exceed six feet. In a multi-screw vessel where the shaft tunnel or thrust block recess space is open from side to side, measure only the space used for purposes of propelling the vessel.
(12) When the propelling machinery is on a bed at the vessel's bottom, the height of the propelling machinery space is measured from the top of the bottom frames or floors.
(d) Request to treat certain framed-in engine room spaces as part of a propelling machinery space. (1) Under §69.117(b)(4), framed-in spaces located above the line of the uppermost complete deck and used for propelling machinery or for admitting light or air to a propelling machinery space are exempt from inclusion in gross tonnage. However, upon written request to a measurement organization listed in §69.15, the vessel owner may elect to have these spaces included in calculating gross tonnage, then deducted from gross tonnage as propelling machinery spaces under paragraph (b)(2)(viii) of this section.
(2) The framed-in space must be safe, seaworthy, and used only for propelling machinery or for the admission of light or air to the propelling machinery space. The length of the space must not exceed the length of the propelling machinery space and the breadth must not exceed one-half of the extreme inside midship breadth of the vessel. Portions of the framed-in space that are plated over are not included in the propelling machinery space.
(3) To exercise the option in paragraph (d)(1) of this section, all of the framed-in space need not be treated as propelling machinery space, but only that portion required to entitle the vessel to have 32 percent of its gross tonnage deducted as an engine room deduction under paragraph (e) of this section.
(e) Calculating the engine room deduction. (1) The engine room deduction is based on a percentage of the vessel's gross tonnage or a percentage of the total propelling machinery space.
(2) For vessels propelled in whole or in part by screw—
(i) If the total propelling machinery space is 13 percent or less of the vessel's gross tonnage, deduct 32/13 times the total propelling machinery space;
(ii) If the total propelling machinery space is more than 13 but less than 20 percent of the vessel's gross tonnage, deduct 32 percent of the vessel's gross tonnage; or
(iii) If the total propelling machinery space is 20 percent or more of the vessel's gross tonnage, deduct either 32 percent of the vessel's gross tonnage or 1.75 times the total propelling machinery space, whichever the vessel's owner elects.
(3) For vessels propelled in whole or in part by paddle-wheel—
(i) If the total propelling machinery space is 20 percent or less of the vessel's gross tonnage, deduct 37/20 times the total propelling machinery space;
(ii) If the total propelling machinery space is more than 20 but less than 30 percent of the vessel's gross tonnage, deduct 37 percent of the vessel's gross tonnage; or
(iii) If the total propelling machinery space is 30 percent or more of the vessel's gross tonnage, deduct either 37 percent of the vessel's gross tonnage or 1.5 times the total propelling machinery space, whichever the vessel's owner elects.
[CGD 87–015b, 54 FR 37657, Sept. 12, 1989; 54 FR 40240, Sept. 29, 1989]
§ 69.123 Figures.
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Subpart D—Dual Measurement System
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§ 69.151 Purpose.
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This subpart prescribes measurement requirements for the assignment of either one gross and one net tonnage or two gross and two net tonnages to vessels under the Dual Measurement System.
§ 69.153 Application of other laws.
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(a) If a vessel is assigned two gross tonnages under §69.175(b), the higher gross tonnage is the tonnage used when applying inspection, manning, and load line laws and regulations to the vessel.
(b) Tonnage marks are not to be construed as additional load line marks. Whether or not a tonnage mark is submerged under §69.171 has no effect on the applicability of load line laws and regulations.
§ 69.155 Measurement requirements.
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Except as otherwise required by this subpart, the measurement requirements under the Standard Measurement System in subpart C of this part apply to the measurement of vessels under the Dual Measurement System.
§ 69.157 Definitions.
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Terms used in this subpart that are defined in §69.103 have the same meaning as in §69.103, except the terms listed below. As used in this subpart,—
Gross tonnage is defined in §69.161(a).
Line for fresh and tropical waters means the line described in §69.177(b)(2).
Line of the second deck means the line described in §69.181.
Line of the uppermost complete deck means a longitudinal line at the underside of the uppermost complete deck or, if that deck is stepped, the longitudinal line of the underside of the lowest portion of that deck parallel with the upper portions of that deck.
Net tonnage is defined in §69.161(b).
Second deck means the next deck below the uppermost complete deck that meets the following:
(a) Is continuous athwartships and in a fore-and-aft direction at least between peak bulkheads, even though the deck may have interruptions or openings due to propelling machinery spaces, to hatch and ventilation trunks not extending longitudinally completely between main transverse bulkheads, to ladder and stairway openings, to chain lockers, or to cofferdams.
(b) Is fitted as an integral and permanent part of the vessel.
(c) Has proper covers to all main hatchways.
(d) Does not have steps the total of which exceed 48 inches in height.
Tonnage deck means, for a vessel with only one deck, the uppermost complete deck and, for a vessel with a second deck, the second deck.
Tonnage mark means the line described in §69.177(a)(2).
§ 69.159 Application for measurement services.
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Applications for measurement services under this subpart must include the application information and plans required for the Standard Measurement System under §69.105. The application must indicate whether a line for fresh and tropical waters is requested under §69.177(b) and, for vessels with more than one deck, indicate whether one or two sets of tonnages are desired under §69.175.
§ 69.161 Gross and net tonnages.
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(a) Gross tonnage means the tonnage of a vessel, less certain spaces exempt under §69.169, and is the sum of the following:
(1) Under-deck tonnage (§69.163).
(2) Between-deck tonnage (§69.165)
(3) Superstructure tonnage (§69.167)
(4) Excess hatchway tonnage (§69.115)
(5) Tonnage of framed-in propelling machinery spaces included in calculating gross tonnage (§69.121(d)(1)).
(b) Net tonnage means gross tonnage less deductions under §69.119 and §69.121.
§ 69.163 Under-deck tonnage.
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The under-deck tonnage provisions in §69.109 apply; except that, under the Dual Measurement System, spaces between the line of the tonnage deck and the tonnage deck itself due to a stepped tonnage deck are included in under-deck tonnage.
§ 69.165 Between-deck tonnage.
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The between-deck tonnage provisions in §69.111 apply, except that, under the Dual Measurement System, between-deck space extends from the tonnage deck to the uppermost complete deck, rather than from the line of the tonnage deck to the line of the uppermost complete deck.
§ 69.167 Superstructure tonnage.
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The superstructure tonnage provisions in §69.113 apply; except that, under the Dual Measurement System, spaces between the line of the uppermost complete deck and the uppermost complete deck itself due to a stepped uppermost complete deck are not included in the superstructure tonnage.
§ 69.169 Spaces exempt from inclusion in gross tonnage.
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The tonnage of the following spaces is exempt from inclusion in gross tonnage:
(a) Spaces listed in §69.117(b) when located within the superstructure.
(b) Spaces listed in §69.117(c)(1) through (c)(3) when located above, but not on, the uppermost complete deck.
(c) Spaces listed in §69.117(f), regardless of location.
(d) Spaces available for carrying dry cargo and stores when located on or above the uppermost complete deck.
(e) When a vessel is assigned a tonnage mark and the tonnage mark is not submerged,—
(1) Spaces listed in §69.117(b) when located between the uppermost complete deck and the second deck;
(2) Spaces listed in §69.117(c)(1) through (c)(3) when located on the uppermost complete deck; and
(3) Spaces available for carrying dry cargo and stores when located between the uppermost complete deck and the second deck.
[CGD 87–015b, 54 FR 37657, Sept. 12, 1989, as amended by CGD 92–058, 57 FR 59938, Dec. 17, 1992]
§ 69.171 When the tonnage mark is considered submerged.
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For the purpose of this subpart, a tonnage mark is considered submerged when—
(a) In salt or brackish water, the upper edge of the tonnage mark is submerged; and
(b) In fresh or tropical water, the upper edge of the line for fresh and tropical waters is submerged.
§ 69.173 Tonnage assignments for vessels with only one deck.
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A vessel without a second deck is assigned only one gross and one net tonnage. In calculating the gross tonnage, only the exemptions in §69.169 (a) through (d) are allowed. Markings under §69.177 are not permitted on these vessels.
§ 69.175 Tonnage assignments for vessels with a second deck.
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(a) At the option of the vessel owner, a vessel having a second deck is assigned either two gross and two net tonnages or one gross and one net tonnage.
(b) If two gross and two net tonnages are assigned, the higher tonnages (i.e. those based only on exemptions under §69.169 (a) through (d)) are applicable when the upper edge of the tonnage mark is submerged and the lower tonnages (i.e. those based only on all exemptions under §69.169) are applicable when the upper edge of the tonnage mark is not submerged.
(c) If only the low gross and low net tonnages, as calculated under paragraph (b) of this section, are assigned, these tonnages are applicable at all times. On these vessels, the tonnage mark must be located in accordance with §69.177(a)(6) at the level of the uppermost part of the load line grid.
§ 69.177 Markings.
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(a) Tonnage mark. (1) All vessels with a second deck that are measured under the Dual Measurement System must have, on each side of the vessel, a tonnage mark, and an inverted triangle identifying the tonnage mark, as described and located under this section. (See the figure in §69.183(a).) Vessels with only one deck are not assigned markings under this section.
(2) The tonnage mark is a horizontal line 15 inches long and one inch wide. The tonnage mark must be designated by a welded bead or other permanent mark 15 inches long placed along the top edge of the tonnage mark.
(3) Above the tonnage mark is placed an inverted equilateral triangle, each side of which is 12 inches long and one inch wide, with its apex touching the upper edge of the center of the tonnage mark.
(4) If the vessel has a load line mark, the longitudinal location of the center of the tonnage mark must be between 21 inches and six feet six inches aft of the vertical centerline of the load line ring. (See the figures in §69.183 (b) and (c).) If the vessel does not have a load line mark, the center of the tonnage mark must be located amidships.
(5) Except as under paragraph (a)(6) of this section, the upper edge of the tonnage mark must be located below the line of the second deck at the distance indicated in Table 69.177(a)(5). (See the figure in §69.183(b).)
Table 69.177(a)(5)_Minimum Distance in Inches Between the Tonnage Mark and the Line of the Second Deck
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L divided by D
L (in feet) -----------------------------------------------------------------------
12 13 14 15 16 17 18 19 20
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220 and under........................... 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0
230..................................... 3.2 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0
240..................................... 4.7 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0
250..................................... 6.3 3.3 2.0 2.0 2.0 2.0 2.0 2.0 2.0
260..................................... 8.0 4.8 2.1 2.0 2.0 2.0 2.0 2.0 2.0
270..................................... 9.9 6.4 3.5 2.0 2.0 2.0 2.0 2.0 2.0
280..................................... 11.8 8.1 4.9 2.1 2.0 2.0 2.0 2.0 2.0
290..................................... 13.9 9.9 6.5 3.5 2.0 2.0 2.0 2.0 2.0
300..................................... 16.0 11.7 8.1 4.9 2.1 2.0 2.0 2.0 2.0
310..................................... 18.3 13.7 9.8 6.4 3.5 2.0 2.0 2.0 2.0
320..................................... 20.7 15.8 11.7 8.1 4.9 2.1 2.0 2.0 2.0
330..................................... 23.2 18.0 13.6 9.8 6.4 3.5 2.0 2.0 2.0
340..................................... 25.9 20.4 15.7 11.6 8.1 4.9 2.1 2.0 2.0
350..................................... 28.7 22.9 17.9 13.6 9.8 6.5 3.6 2.0 2.0
360..................................... 31.7 25.5 20.2 15.7 11.7 8.2 5.0 2.2 2.0
370..................................... 34.7 28.3 22.717.9 13.6 9.9 6.6 3.7 2.0 (continued)