Current as of: Oct. 2009
(a) Defined. ``Under-deck tonnage'' means the tonnage of the space below the line of the tonnage deck, as that volume is calculated under this section.
(b) Method of calculating tonnage. Under-deck tonnage is calculated by applying Simpson's first rule using the tonnage length and the areas of the transverse sections prescribed by this section.
(c) Identifying the tonnage deck. In vessels with two or less decks, the tonnage deck is the uppermost complete deck. In vessels with more than two decks, the tonnage deck is the second deck from the keel as determined in paragraph (d) of this section.
(d) Enumerating the decks to identify the second deck from the keel. Only decks without openings that permit space below to be exempt from inclusion in under-deck tonnage are enumerated. Partial decks are not considered decks for the purpose of enumerating decks. However, the presence of engine and boiler casings, peak tanks, or cofferdams that penetrate a deck do not disqualify the deck from being enumerated.
(e) Identifying the line of the tonnage deck. (1) If the tonnage deck runs in a continuous line from stem to stern, the line of the tonnage deck is the longitudinal line at the underside of the tonnage deck.
(2) If the tonnage deck runs at different levels from stem to stern, the line of the tonnage deck is the longitudinal line of the underside of the lowest portion of that deck parallel with the upper portions of that deck. (See Sec. 69.123, figures 1 and 2.) Spaces between the line of the tonnage deck and the higher portions of that deck are not included in under-deck tonnage.
(f) Tonnage length. (1) ``Tonnage length'' means the length of a horizontal straight line measured at the centerline of the vessel from the point forward where the line of the tonnage deck intersects the line of the inboard faces of the ordinary side frames to the point aft where the line of the tonnage deck intersects the inboard face of the transom frames or cant frames. (See Sec. 69.123, figure 3.)
(2) For a vessel having a headblock or square end with framing which extends from the tonnage deck to the bottom of the vessel, the tonnage length terminates on the inboard face of the head block or end framing. When a headblock extends inboard past the face of the end side frames or when the headblock plates are excessive in length, the tonnage length terminates at the extreme end of the vessel less a distance equal to the thickness of an ordinary side frame and shell plating. (See Sec. 69.123, figure 4.)
(3) For a vessel having a square bow or stern and tonnage deck with camber, the effect of the camber on the tonnage length must be considered. The tonnage length must be measured below the tonnage deck at a distance equal to one-third of round camber and one-half of straight pitch camber.
(g) Division of vessel into transverse sections. (1) Except as under paragraph (m)(1)(iii) of this section, the tonnage length is divided into an even number of equal parts as indicated in the following table:------------------------------------------------------------------------
50 ft. or less.........
Over 50 ft. but not
exceeding 100 ft.3...................................
Over 100 ft. but not
exceeding 150 ft.4...................................
Over 150 ft. but not
exceeding 200 ft.5...................................
Over 200 ft. but not
exceeding 250 ft.6...................................
Over 250 ft............
(2) Transverse sections are cut at each end of the tonnage length and at each point of division of the tonnage length. Intervals and one-third intervals between the points of division are measured to the nearest thousandth of a foot. (See Sec. 69.123 figures 5 and 6.)
(h) Depths of transverse sections. (1) Transverse section depths are measured at each point of division of the tonnage length at the centerline of the vessel from a point below the line of the tonnage deck equal to one-third of the camber or to one-half of the pitch of the beam down to the upper side of the ordinary frames, floors, longitudinals, or tank top of a cellular double bottom, as the case may be.
(2) When a depth falls at a point where the tank top of a double bottom has a straight fall from centerline to the wings, the depth terminates at one-half of the height of fall. (See Sec. 69.123 figure 8.)
(3) When a depth falls at a point where the tank top of a double bottom rises from the centerline to the wings, the depth terminates at one-half the dead rise. (See Sec. 69.123, figure 9.)
(4) The depth at the midpoint of the tonnage length or, when a vessel is measured in parts, the depth at the midpoint of each part determines the number of equal parts into which each depth is divided, as follows:
(i) If the midpoint depth is 16 feet or less, each depth is divided into four equal parts. If the midpoint depth exceeds 16 feet, each depth is divided into six equal parts. (See Sec. 69.123, figure 7.)
(ii) The interval between the points of division of a depth and one-third intervals are carried to the nearest hundredth of a foot.
(i) Breadths of transverse sections. (1) Transverse section breadths are measured horizontally at each point of division of each depth and also at the upper and lower points of each depth. Breadths are measured to the inboard face of the ordinary frames or to the line of the ordinary frames. Breadths are measured parallel to each other and at right angle to the vessel's centerline. (See Sec. 69.123, figure 7.)
(2) Upper breadths are not reduced by measuring to deck-beam brackets. In cases of camber when an upper breadth passes through the deck (see Sec. 69.123, figure 7), the breadth is measured to the line of the side frames at the under side of the deck projected vertically up to the height of the upper breadth.
(3) Bottom breadths are measured only as far as the flat of the floor extends. (See Sec. 69.123, figures 7 and 10.) When bottom frames rise immediately from the flat keel, bottom breadths are equal to the breadth of the flat keel. Where there is no double bottom and where there is dead rise of the bottom out to the sides of the vessel, bottom breadths are equal to the part of the bottom plating not affected by dead rise.
(4) Bottom breadths falling in way of a double bottom, the top of which rises or falls from certerline to the wings, are measured between the inboard faces of the frame brackets which connect the double bottom with the frames. (See Sec. 69.123, figures 8 and 9.)
(j) Measuring spaces having ceiling. The maximum allowance for terminating measurements on ceiling is three inches on the bottom frames or tank top and three inches on each side frame. When ceiling is less than three inches thick, only the actual thickness is allowed. When ceiling is fitted on a platform directly above the bottom frames, depths are measured down through the platform to the upper side of the frames and the allowable ceiling on the platform is then deducted.
(k) Area of transverse sections. (1) A transverse section at an end of the tonnage length may not yield area, except in vessels (such as barges) with an upright bow or stern.
(2) The breadths of each transverse section are numbered from above, the upper being ``1'', the second down being ``2'', and so on to the lowest.
(3) Multiply the even numbered breadths by four and the odd numbered breadths by two, except for the first and last breadths, which are multiplied by one.
(4) Add together the products from paragraph (k)(3) of this section.
(5) Multiply the sum from paragraph (k)(4) of this section by one-third of the interval between the breadths. The product is the area of the transverse section.
(l) Tonnage. (1) Number the transverse sections successively ``1'', ``2'', and so forth, beginning at the bow.
(2) Multiply the area of the even numbered sections by four and the area of the odd numbered sections by two, except the first and last sections, which are multiplied by one.
(3) Add together the products from paragraph (l)(2) of this section and multiply the sum by one-third of the interval between the sections. The product is the volume under-deck.
(4) The volume under-deck is divided by 100 and is, subject to exemptions, the under-deck tonnage.
(m) Steps in double bottom. (1) The tonnage length of a vessel having a step exceeding six inches in height in its double bottom is divided into longitudinal parts at the step. Each part is subdivided as follows to determine the number of transverse sections:
(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]
State Laws: Watercraft
|Alabama||Alabama Code > Title 33 > Chapter 5 - Registration And Operation Of Vessels|
|Alabama Code > Title 33 > Chapter 6 - Discharge Of Litter And Sewage From Watercraft|
|Alabama Code > Title 33 > Chapter 6A - Recreational Vessel And Residence Boat Sewage Discharges Regulated|
|Alaska||Alaska Statutes Chapter 05.25 - Watercraft|
|Alaska Statutes Chapter 30.30 - Abandoned And Derelict Vessels|
|Arizona||Arizona Laws > Title 5 > Chapter 3 - Boating And Water Sports|
|California||California Harbors and Navigation Code > Division 3 - Vessels|
|California Harbors and Navigation Code > Division 4 - Masters, Crews And Cargoes|
|California Harbors and Navigation Code > Division 5 - Pilots For Monterey Bay And The Bays Of San Francisco, San Pablo, And Suisun|
|Connecticut||Connecticut General Statutes > Title 15 > Chapter 268 - Boating|
|Delaware||Delaware Code Title 23 > Chapter 21 - Motorboats|
|Delaware Code Title 23 > Chapter 22 - Boating Safety|
|Delaware Code Title 23 > Chapter 23 - Operation Of A Vessel Or Boat While Under The Influence Of Intoxicating Liquor And/Or Drugs|
|Delaware Code Title 23 > Chapter 24 - Exemptions From Civil Liability For Rendering Vessel Traffic Information Services|
|Florida||Florida Statutes > Title XXIV - Vessels|
|Florida Regulations Chapter 61B-60 - Yacht and Ship Brokers|
|Florida Regulations > Division 68D - Vessel Registration and Boating Safety|
|Idaho||Idaho Code Title 67 > Chapter 70 - Idaho Safe Boating Act|
|Illinois||Illinois Compiled Statutes > 625 ILCS 45 - Boat Registration and Safety Act|
|Indiana||Indiana Code > Title 9 > Article 31 - Watercraft Titling And Registration|
|Indiana Code > Title 25 > Article 28 - Boat Pilots|
|Kansas||Kansas Statutes > Chapter 32 > Article 11 - Boating And Water Activities|
|Maine||Maine Revised Statutes > Title 10 > Chapter 204-B - Watercraft Manufacturers, Distributors And Dealers|
|Maine Revised Statutes > Title 10 > Chapter 212-A - Maine Marina And Boatyard Storage Act|
|Maine Revised Statutes > Title 10 > Chapter 627 - Vessels|
|Maine Revised Statutes > Title 12 > Chapter 935 - Watercraft And Airmobiles|
|Maine Revised Statutes Title 23 > Chapter 412 - Waterborne Transportation|
|Massachusetts||Massachusetts General Laws > Part I > Title XIV > Chapter 90B - Motorboats And Other Vessels|
|Michigan||Michigan Laws > Chapter 123 > Act 68 of 1957 - Regulation Of Houseboats|
|Michigan Laws > Chapter 445 > Act 88 of 1989 - Watercraft And Outboard Motor Manufacturers, Distributors, And Dealers|
|Minnesota||Minnesota Statutes Chapter 86B - Water Safety, Watercraft, and Watercraft Titling|
|Missouri||Missouri Laws > Title XIX > Chapter 306 - Watercraft Regulation and Licensing--State Water Patrol|
|Nevada||Nevada Revised Statutes > Chapter 488 - Watercraft|
|New Hampshire||New Hampshire Revised Statutes > Chapter 270-A - Use Of Houseboats|
|New Hampshire Revised Statutes > Chapter 270-B - Abandoned Boats|
|New Hampshire Revised Statutes > Chapter 270-D - Boating And Water Safety On New Hampshire Public Waters|
|New Hampshire Revised Statutes > Chapter 270-E - Vessel Registration And Numbering|
|New Mexico||New Mexico Statutes Chapter 66 > Article 12 - Boating|
|New Mexico Statutes Chapter 66 > Article 13 - Boating While Intoxicated|
|New York||New York Laws - General Business > Article 38 - Vessel Dealer Agreements|
|New York||New York Laws > General Business > Article 38 - Vessel Dealer Agreements|
|North Carolina||North Carolina General Statutes Chapter 75A - Boating and Water Safety|
|North Dakota||North Dakota Code > Chapter 20.1-13 - Boating Regulation|
|North Dakota Code > Chapter 20.1-13.1 - Intoxication Testing of Boat Operators|
|North Dakota Code > Chapter 20.1-17 - Aquatic Nuisance Species|
|Ohio||Ohio Code > Title 15 > Chapter 1547 - Watercraft And Waterways|
|Ohio Code > Title 15 > Chapter 1548 - Watercraft Certificates Of Title|
|Ohio Code > Title 45 > Chapter 4585 - Actions Relating To Watercraft|
|Oregon||Oregon Statutes > Title 61 - Small Watercraft|
|Rhode Island||Rhode Island General Laws > Chapter 46-8. Registration of Outboard Motors|
|Rhode Island General Laws > Chapter 46-9. Pilots â€“ Rhode Island Sound, Narragansett Bay, Sakonnet River, and Tributaries|
|Rhode Island General Laws > Chapter 46-9.1. Pilotsâ€“Block Island Sound|
|Rhode Island General Laws > Chapter 46-22. Regulation of Boats|
|Rhode Island General Laws > Chapter 46-22.1. Uniform Boat Title Act|
|Rhode Island General Laws > Chapter 46-22.2. Alcohol Boating Safety Act|
|Rhode Island General Laws > Chapter 46-27. Personal Watercraft Safety Act|
|South Carolina||South Carolina Code > Title 29 > Chapter 9 - Liens On Ships And Vessels|
|South Carolina Code > Title 50 > Chapter 21 - Equipment And Operation Of Watercraft|
|South Carolina Code > Title 50 > Chapter 23 - Watercraft And Outboard Motors|
|South Carolina Code > Title 50 > Chapter 25 - Boating And Surfing At Particular Localities|
|South Dakota||South Dakota Laws > Title 32 > Chapter 03A - Title, Registration And Taxation Of Boats|
|South Dakota Laws > Title 32 > Chapter 07B - Regulation Of Boat Dealers|
|South Dakota Laws > Title 42 > Chapter 8 - Watercraft|
|Tennessee||Tennessee Code > Title 69 > Chapter 9 - Boating Regulation|
|Texas||Texas Civil Statutes > Title 132 > Chapter 19 - Boat Or Motor Manufacturers, Distributors, And Dealers|
|Utah||Utah Code > Title 73 > Chapter 18 - State Boating Act|
|Utah Code > Title 73 > Chapter 18 - Boating - Litter and Pollution Control|
|Utah Code > Title 73 > Chapter 18 - Water Safety|
|Utah Code > Title 73 > Chapter 18 - Financial Responsibility of Motorboat Owners and Operators Act|
|Vermont||Vermont Statutes > Title 25 > Chapter 1 - Operation of Vessels|
|Virginia||Virginia Code Title 29.1 > Chapter 7 - Boating Laws|
|Virginia Code Title 29.1 > Chapter 8 - Watercraft Dealer Licensing Act|
|Virginia Code Title 62.1 > Chapter 18 - Protection of Aids to Navigation|
|Wisconsin||Wisconsin Statutes > Chapter 30 > Subchapter V - Regulation Of Boating|