{"data":{"id":"us/46-cfr-69.177","jurisdiction":"us","citation":"46 CFR 69.177","heading":"Markings.","body":"(a) Tonnage mark. (1) All vessels with a second deck that are measured under this subpart 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.\n(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.\n(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.\n(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.\n(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).)\nTable 69.177(a)(5)—Minimum Distance in Inches Between the Tonnage Mark and the Line of the Second Deck\nL (in feet) L divided by D\n12 13 14 15 16 17 18 19 20\n220 and under 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0\n230 3.2 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0\n240 4.7 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0\n250 6.3 3.3 2.0 2.0 2.0 2.0 2.0 2.0 2.0\n260 8.0 4.8 2.1 2.0 2.0 2.0 2.0 2.0 2.0\n270 9.9 6.4 3.5 2.0 2.0 2.0 2.0 2.0 2.0\n280 11.8 8.1 4.9 2.1 2.0 2.0 2.0 2.0 2.0\n290 13.9 9.9 6.5 3.5 2.0 2.0 2.0 2.0 2.0\n300 16.0 11.7 8.1 4.9 2.1 2.0 2.0 2.0 2.0\n310 18.3 13.7 9.8 6.4 3.5 2.0 2.0 2.0 2.0\n320 20.7 15.8 11.7 8.1 4.9 2.1 2.0 2.0 2.0\n330 23.2 18.0 13.6 9.8 6.4 3.5 2.0 2.0 2.0\n340 25.9 20.4 15.7 11.6 8.1 4.9 2.1 2.0 2.0\n350 28.7 22.9 17.9 13.6 9.8 6.5 3.6 2.0 2.0\n360 31.7 25.5 20.2 15.7 11.7 8.2 5.0 2.2 2.0\n370 34.7 28.3 22.7 17.9 13.6 9.9 6.6 3.7 2.0\n380 38.0 31.1 25.3 20.2 15.7 11.8 8.3 5.2 2.4\n390 41.3 34.1 27.9 22.6 17.9 13.8 10.1 6.8 3.8\n400 44.8 37.2 30.7 25.0 20.1 15.8 11.9 8.4 5.3\n410 48.2 40.3 33.5 27.7 22.6 18.1 14.0 10.4 7.2\n420 51.5 43.4 36.4 30.4 25.2 20.6 16.4 12.7 9.7\n430 54.8 46.5 39.4 33.3 27.9 23.2 19.0 15.2 11.8\n440 58.4 49.9 42.6 36.4 30.9 26.0 21.7 17.8 14.4\n450 62.1 53.4 46.0 39.6 33.9 29.0 24.6 20.6 17.1\n460 65.9 57.0 49.5 42.9 37.1 32.1 27.6 23.5 19.9\n470 69.8 60.7 53.0 46.3 40.4 35.2 30.6 26.5 22.8\n480 73.7 64.4 56.5 49.7 43.7 38.4 33.7 29.5 25.7\n490 77.5 68.1 60.0 53.0 46.9 41.5 36.7 32.4 28.5\n500 81.2 71.6 63.4 56.2 50.0 44.5 39.6 35.2 31.2\n510 84.9 75.1 66.7 59.4 53.0 47.4 42.4 37.9 33.9\n520 88.4 78.4 69.9 62.4 55.9 50.2 45.1 40.5 36.4\n530 91.8 81.6 72.9 65.3 58.7 52.9 47.7 43.0 38.8\n540 95.2 84.8 75.9 68.1 61.4 55.5 50.2 45.4 41.2\n550 98.4 87.8 78.8 70.9 64.0 58.0 52.6 47.8 43.4\n560 101.6 90.8 81.6 73.6 66.6 60.5 55.0 50.1 45.6\n570 104.8 93.8 84.4 76.3 69.2 62.9 57.3 52.3 47.8\n580 107.9 96.8 87.2 78.9 71.7 65.3 59.6 54.5 49.9\n590 111.0 99.7 90.0 81.5 74.2 67.7 61.9 56.7 52.0\n600 114.0 102.5 92.6 84.0 76.5 69.9 64.0 58.8 54.0\n610 117.0 105.3 95.2 86.5 78.9 72.1 66.2 60.8 56.0\n620 120.0 108.0 97.8 88.9 81.2 74.4 68.3 62.8 58.0\n630 122.9 110.7 100.4 91.3 83.5 76.6 70.4 64.8 59.9\n640 125.7 113.4 102.9 93.7 85.8 78.7 72.4 66.8 61.7\n650 128.6 116.1 105.4 96.1 88.0 80.8 74.4 68.7 63.6\n660 131.4 118.7 107.8 98.3 90.1 82.8 76.3 70.6 65.3\n670 134.2 121.2 110.2 100.6 92.2 84.8 78.3 72.4 67.1\n680 136.9 123.8 112.8 102.9 94.3 86.8 80.2 74.2 68.9\n690 139.6 126.3 115.0 105.1 96.4 88.8 82.1 76.0 70.6\n700 142.3 128.8 117.3 107.3 98.5 90.8 83.9 77.8 72.3\n710 144.9 131.3 119.6 109.4 100.5 92.7 85.7 79.5 73.9\n720 147.5 133.7 121.8 111.5 102.5 94.6 87.5 81.2 75.5\n730 150.1 136.1 124.0 113.6 104.5 96.5 89.3 82.9 77.1\n740 152.7 138.5 126.2 115.7 106.5 98.3 91.5 84.5 78.7\n750 155.3 140.8 128.5 117.8 108.4 100.1 92,8 86.1 80.3\n760 157.8 143.1 130.6 119.7 110.3 101.9 94.4 87.8 81.7\n770 160.2 145.4 132.7 121.7 112.1 103.6 96.0 89.3 83.2\n780 162.6 147.6 134.8 123.7 113.9 105.3 97.6 90.8 84.7\n790 165.1 149.9 136.9 125.6 115.7 107.0 99.2 92.3 86.1\n800 167.5 152.1 138.9 127.4 117.4 108.6 100.8 93.8 87.4\nL = 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.\nD = The vertical distance in feet from the top of the flat keel of the vessel to the line of the second deck.\nEXAMPLE (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.\nEXAMPLE (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:\nL Table L/D = 15 Actual L/D = 15.17 Table L/D = 16\nTable 420 30.4 25.2\nActual 424.80 r a s\nTable 430 33.3 27.9\nInterpolation:\nr = 30.4 + 0.48 (33.3−30.4) = 31.79\ns = 25.2 + 0.48 (27.9−25.2) = 26.50\na = r−0.17 (r−s) = 31.79−0.17 (31.79−26.50) = 30.89 inches\n(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:\n(i) Vessels assigned only one gross and one net register tonnage under § 69.175(c).\n(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.\n(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.\n(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).)\n(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.\n(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.\n(c) Freeboard deck mark. A vessel assigned two gross and two net register 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.\n(d) The line of the second deck. The line of the second deck must not be marked on the side of the vessel, except in the case of a freeboard deck line mark placed at the location of the second deck if the second deck is the actual freeboard deck for purposes of a vessel's load line assignment.\n(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.","path":["Title 46—Shipping","CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY","SUBCHAPTER G—DOCUMENTATION AND MEASUREMENT OF VESSELS","PART 69—MEASUREMENT OF VESSELS","Subpart D —Dual Regulatory Measurements System"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-46.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:22Z","sha256":"41474b99cdb8f8de02bdd6c6409a2dfac15eb058ae4561c69b0253690c0bd328","source_id":"us-cfr","stale":true,"prev":"us/46-cfr-69.175","next":"us/46-cfr-69.179"},"notice":"GroundRules: Original legal text. Not legal advice."}