46 C.F.R. Subpart D—Dual Measurement System
Title 46 - Shipping
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. (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. 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. 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). 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. (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. 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. 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. 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. 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] 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. 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. (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. (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).) (6) For the following vessels with a load line mark, the upper edge of the tonnage mark must be located at the level of the uppermost part of the load line grid: (i) Vessels assigned only one gross and one net tonnage under §69.175(c). (ii) Vessels for which a load line assigning authority certifies that the vessel's load line mark was located as though the second deck were the freeboard deck. (b) Line for fresh and tropical waters. (1) Except as under paragraph (b)(4) of this section, a horizontal line for fresh and tropical waters may be assigned at the vessel owner's request. (2) The line must be nine inches long and one inch wide and located above and to the left of the tonnage mark at a distance equal to one forty-eighth of the distance from the top of the flat keel to the tonnage mark. The tonnage mark and the line for fresh and tropical waters must be connected by a vertical line one inch wide. (See the figure in §69.183(a).) (3) The line for fresh and tropical waters must be designated by a welded bead or other permanent mark nine inches long placed along the upper edge of the line. (4) For vessels with a load line mark, if the load line assigning authority certifies that the load line mark was located as though the second deck were the freeboard deck, a line for fresh and tropical waters must not be placed on the vessel. (c) Freeboard deck mark. A vessel assigned two gross and two net tonnages which has more than one deck and no load line mark assigned must have a mark on each side of the vessel with the same dimensions and location as the freeboard deck line mark under §42.13–20 of this chapter, except that the mark must be located directly above the tonnage mark. (d) The line of the second deck. The line of the second deck must not be marked on the side of the vessel. (e) Color of markings. All markings under this section must be maintained in either a light color on a dark background or a dark color on a light background. (a) Before a certificate of measurement is issued for a vessel requiring a tonnage mark, a certification by a measurement organization under §69.15 that all markings meet the requirements of this subpart is required. (b) The Coast Guard, at any time, may verify markings under this subpart. (a) If the second deck is not stepped, the line of the second deck is the longitudinal line of the underside of the second deck at the side of the hull. (b) If the second deck is stepped (as in the examples following this paragraph), the line of the second deck is a longitudinal line extended parallel to each portion of the second deck and located at the height of the underside of the amidships portion of the second deck at the side of the hull— (1) Plus, for each stepped portion of the second deck higher than the second deck at amidships, a distance equal to the length of the stepped portion divided by the total length of the second deck times the height that the step is above the height of the amidship portion of the second deck; and (2) Minus, for each stepped portion of the second deck lower than the second deck at amidships, a distance equal to the length of the stepped portion divided by the total length of the second deck times the height that the amidship portion of the second deck is above the height of the step. (a) Tonnage mark with an equilateral triangle and a line for fresh and tropical waters.
W= (b) Tonnage mark location if the load line mark is not placed as though the second deck were the freeboard deck.
k=a distance between 21 inches and six feet six inches. a=distance derived from Table 69.177(a)(5). (c)—Tonnage mark location if the load line mark is placed as though the second deck were the freeboard deck.
k=a distance between 21 inches and six feet six inches. a=the distance between the line of the second deck and the uppermost part of the load line grid.
Title 46: Shipping
PART 69—MEASUREMENT OF VESSELS
Subpart D—Dual Measurement System
§ 69.151 Purpose.
§ 69.153 Application of other laws.
§ 69.155 Measurement requirements.
§ 69.157 Definitions.
§ 69.159 Application for measurement services.
§ 69.161 Gross and net tonnages.
§ 69.163 Under-deck tonnage.
§ 69.165 Between-deck tonnage.
§ 69.167 Superstructure tonnage.
§ 69.169 Spaces exempt from inclusion in gross tonnage.
§ 69.171 When the tonnage mark is considered submerged.
§ 69.173 Tonnage assignments for vessels with only one deck.
§ 69.175 Tonnage assignments for vessels with a second deck.
§ 69.177 Markings.
Table 69.177(a)(5)_Minimum Distance in Inches Between the Tonnage Mark and the Line of the Second Deck---------------------------------------------------------------------------------------------------------------- L divided by D L (in feet) ----------------------------------------------------------------------- 12 13 14 15 16 17 18 19 20----------------------------------------------------------------------------------------------------------------220 and under........................... 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0230..................................... 3.2 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0240..................................... 4.7 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0250..................................... 6.3 3.3 2.0 2.0 2.0 2.0 2.0 2.0 2.0260..................................... 8.0 4.8 2.1 2.0 2.0 2.0 2.0 2.0 2.0270..................................... 9.9 6.4 3.5 2.0 2.0 2.0 2.0 2.0 2.0280..................................... 11.8 8.1 4.9 2.1 2.0 2.0 2.0 2.0 2.0290..................................... 13.9 9.9 6.5 3.5 2.0 2.0 2.0 2.0 2.0300..................................... 16.0 11.7 8.1 4.9 2.1 2.0 2.0 2.0 2.0310..................................... 18.3 13.7 9.8 6.4 3.5 2.0 2.0 2.0 2.0320..................................... 20.7 15.8 11.7 8.1 4.9 2.1 2.0 2.0 2.0330..................................... 23.2 18.0 13.6 9.8 6.4 3.5 2.0 2.0 2.0340..................................... 25.9 20.4 15.7 11.6 8.1 4.9 2.1 2.0 2.0350..................................... 28.7 22.9 17.9 13.6 9.8 6.5 3.6 2.0 2.0360..................................... 31.7 25.5 20.2 15.7 11.7 8.2 5.0 2.2 2.0370..................................... 34.7 28.3 22.7 17.9 13.6 9.9 6.6 3.7 2.0380..................................... 38.0 31.1 25.3 20.2 15.7 11.8 8.3 5.2 2.4390..................................... 41.3 34.1 27.9 22.6 17.9 13.8 10.1 6.8 3.8400..................................... 44.8 37.2 30.7 25.0 20.1 15.8 11.9 8.4 5.3410..................................... 48.2 40.3 33.5 27.7 22.6 18.1 14.0 10.4 7.2420..................................... 51.5 43.4 36.4 30.4 25.2 20.6 16.4 12.7 9.7430..................................... 54.8 46.5 39.4 33.3 27.9 23.2 19.0 15.2 11.8440..................................... 58.4 49.9 42.6 36.4 30.9 26.0 21.7 17.8 14.4450..................................... 62.1 53.4 46.0 39.6 33.9 29.0 24.6 20.6 17.1460..................................... 65.9 57.0 49.5 42.9 37.1 32.1 27.6 23.5 19.9470..................................... 69.8 60.7 53.0 46.3 40.4 35.2 30.6 26.5 22.8480..................................... 73.7 64.4 56.5 49.7 43.7 38.4 33.7 29.5 25.7490..................................... 77.5 68.1 60.0 53.0 46.9 41.5 36.7 32.4 28.5500..................................... 81.2 71.6 63.4 56.2 50.0 44.5 39.6 35.2 31.2510..................................... 84.9 75.1 66.7 59.4 53.0 47.4 42.4 37.9 33.9520..................................... 88.4 78.4 69.9 62.4 55.9 50.2 45.1 40.5 36.4530..................................... 91.8 81.6 72.9 65.3 58.7 52.9 47.7 43.0 38.8540..................................... 95.2 84.8 75.9 68.1 61.4 55.5 50.2 45.4 41.2550..................................... 98.4 87.8 78.8 70.9 64.0 58.0 52.6 47.8 43.4560..................................... 101.6 90.8 81.6 73.6 66.6 60.5 55.0 50.1 45.6570..................................... 104.8 93.8 84.4 76.3 69.2 62.9 57.3 52.3 47.8580..................................... 107.9 96.8 87.2 78.9 71.7 65.3 59.6 54.5 49.9590..................................... 111.0 99.7 90.0 81.5 74.2 67.7 61.9 56.7 52.0600..................................... 114.0 102.5 92.6 84.0 76.5 69.9 64.0 58.8 54.0610..................................... 117.0 105.3 95.2 86.5 78.9 72.1 66.2 60.8 56.0620..................................... 120.0 108.0 97.8 88.9 81.2 74.4 68.3 62.8 58.0630..................................... 122.9 110.7 100.4 91.3 83.5 76.6 70.4 64.8 59.9640..................................... 125.7 113.4 102.9 93.7 85.8 78.7 72.4 66.8 61.7650..................................... 128.6 116.1 105.4 96.1 88.0 80.8 74.4 68.7 63.6660..................................... 131.4 118.7 107.8 98.3 90.1 82.8 76.3 70.6 65.3670..................................... 134.2 121.2 110.2 100.6 92.2 84.8 78.3 72.4 67.1680..................................... 136.9 123.8 112.8 102.9 94.3 86.8 80.2 74.2 68.9690..................................... 139.6 126.3 115.0 105.1 96.4 88.8 82.1 76.0 70.6700..................................... 142.3 128.8 117.3 107.3 98.5 90.8 83.9 77.8 72.3710..................................... 144.9 131.3 119.6 109.4 100.5 92.7 85.7 79.5 73.9720..................................... 147.5 133.7 121.8 111.5 102.5 94.6 87.5 81.2 75.5730..................................... 150.1 136.1 124.0 113.6 104.5 96.5 89.3 82.9 77.1740..................................... 152.7 138.5 126.2 115.7 106.5 98.3 91.5 84.5 78.7750..................................... 155.3 140.8 128.5 117.8 108.4 100.1 92,8 86.1 80.3760..................................... 157.8 143.1 130.6 119.7 110.3 101.9 94.4 87.8 81.7770..................................... 160.2 145.4 132.7 121.7 112.1 103.6 96.0 89.3 83.2780..................................... 162.6 147.6 134.8 123.7 113.9 105.3 97.6 90.8 84.7790..................................... 165.1 149.9 136.9 125.6 115.7 107.0 99.2 92.3 86.1800..................................... 167.5 152.1 138.9 127.4 117.4 108.6 100.8 93.8 87.4 ----------------------------------------------------------------------------------------------------------------L=the length in feet of the line of the second deck at the centerline of the vessel from the inner surface of the frames at the vessel's stem to the inner surface of the frames at the vessel's stern.D=The vertical distance in feet from the top of the flat keel of the vessel to the line of the second deck.EXAMPLE (1) For a vessel in which L=450 feet and L/D=15 feet, read down from the L/D column ``15'' and to the right on the column ``450'' to where the two columns intersect at 39.6. The tonnage mark must be located 39.6 inches below the line of the second deck.EXAMPLE (2) If L or L/D is an intermediate number, the distance ``a'' between the tonnage mark and the line of the second deck must be obtained by linear interpolation. For a vessel in which L=424.80 feet and L/D=15.17:
------------------------------------------------------------------------ Table L/ Actual L/ Table L/ L D=15 D=15.17 D=16------------------------------------------------------------------------Table 420.............................. 30.4 ......... 25.2Actual 424.80.......................... r a sTable 430.............................. 33.3 ......... 27.9------------------------------------------------------------------------Interpolation:r=30.4+0.48 (33.3-30.4)=31.79s=25.2+0.48 (27.9-25.2)=26.50a=r-0.17 (r-s)=31.79-0.17 (31.79-26.50)=30.89 inches
§ 69.179 Certification of markings.
§ 69.181 Locating the line of the second deck.
§ 69.183 Figures.
