(a) The regulations in this part are based on the assumption that the nature and stowage of the cargo, ballast, etc., are such as will secure sufficient stability of the vessel and avoid excessive structural stress.

(b) The regulations in this part are also based on the assumption that, where there are other international requirements relating to stability or subdivision applicable to vessels, these requirements have been met.

[CGFR 68-60, 33 FR 10058, July 12, 1968]

(a) The assigning and issuing authority shall satisfy itself that the general structural strength of the vessel is sufficient for the draft corresponding to the freeboard assigned, and when requested shall furnish pertinent strength information to the Commandant.

(b) Vessels built and maintained in conformity with the requirements of a classification society recognized by the Commandant are considered to possess adequate strength for the purpose of the applicable requirements in this subchapter unless deemed otherwise by the Commandant.

[CGFR 68-60, 33 FR 10058, July 12, 1968, as amended by CGFR 68-126, 34 FR 9013, June 5, 1969]

(a) Vessels with mechanical means of propulsion, or lighters, barges, or other vessels without independent means of propulsion, shall be assigned freeboards in accordance with the provisions of §§ 42.13-1 to 42.20-75, inclusive.

(b) Vessels carrying timber deck cargoes may be assigned, in addition to the freeboards required by paragraph (a) of this section, timber freeboards in accordance with the provisions of §§ 42.25-1 to 42.25-20, inclusive.

(c) Vessels designed to carry sail, whether as the sole means of propulsion or as a supplementary means, and tugs, shall be assigned freeboards in accordance with the provisions of §§ 42.13-1 to 42.20-75, inclusive, and such additional freeboards as determined necessary by the Commandant under the procedure of paragraph (f) of this section.

(d) Vessels of wood or of composite construction, or of other materials the use of which the Commandant has approved, or vessels whose constructional features are such as to render the application of the provisions of §§ 42.13-1 to 42.25-20 unreasonable or impracticable, shall be assigned freeboards as determined necessary by the Commandant under the procedure of paragraph (f) of this section.

(e) The requirements in §§ 42.15-1 to 42.15-80, inclusive, shall apply to every vessel to which a minimum freeboard is assigned. Relaxations from these requirements may be granted to a vessel to which a greater than minimum freeboard is assigned provided the safety conditions of the vessel are determined to be satisfactory under paragraph (f) of this section.

(f) In each case specified by paragraphs (c) to (e) inclusive of this section, the assigning authority shall report to the Commandant the specific matters in which the vessel is deficient or requires special freeboard consideration due to design, arrangement, construction materials, propulsive method, or relaxation of requirements in this part. The report shall also furnish background data and recommendations of the assigning authority (including freeboard additions), as will enable the Commandant to reach a decision.

[CGFR 68-60, 33 FR 10058, July 12, 1968, as amended by CGFR 68-126, 34 FR 9013, June 5, 1969]

(a) Length. The length (L) shall be taken as 96 percent of the total length on a waterline at 85 percent of the least molded depth measured from the top of the keel, or as the length from the foreside of the stem to the axis of the rudder stock on that waterline, if that be greater. In vessels designed with a rake of keel the waterline on which this length is measured shall be parallel to the designed waterline.

(b) Perpendiculars. The forward and after perpendiculars shall be taken at the forward and after ends of the length (L). The forward perpendicular shall coincide with the foreside of the stem on the waterline on which the length is measured.

(c) Amidships. Amidships is at the middle of the length (L).

(d) Breadth. Unless expressly provided otherwise, the breadth (B) is the maximum breadth of the vessel, measured amidships to the molded line of the frame in a vessel with a metal shell and to the outer surface of the hull in a vessel with a shell of any other material.

(e) Molded depth. (1) The molded depth is the vertical distance measured from the top of the keel to the top of the freeboard deck beam at side. In wood and composite vessels the distance is measured from the lower edge of the keel rabbet. Where the form at the lower part of the midship section is of a hollow character, or where thick garboards are fitted, the distance is measured from the point where the line of the flat of the bottom continued inwards cuts the side of the keel.

(2) In vessels having rounded gunwales, the molded depth shall be measured to the point of intersection of the molded lines of the deck and sides, the lines extending as though the gunwale were of angular design.

(3) Where the freeboard deck is stepped and the raised part of the deck extends over the point at which the molded depth is to be determined, the molded depth shall be measured to a line of reference extending from the lower part of the deck along a line parallel with the raised part.

(f) Depth for freeboard (D). (1) The depth for freeboard (D) is the molded depth amidships, plus the thickness of the freeboard deck stringer plate, where fitted, plus

T(L−S)/L if the exposed freeboard deck is sheathed; where: T is the mean thickness of the exposed sheathing clear of deck openings; and S is the total length of superstructures as defined in paragraph (j)(4) of this section.

(2) The depth for freeboard (D) in a vessel having a rounded gunwale with a radius greater than 4 percent of the breadth (B) or having topsides of unusual form is the depth for freeboard of a vessel having a midship section with vertical topsides and with the same round of beam and area of topside section equal to that provided by the actual midship section.

(g) Block coefficient. The block coefficient (Cb) is given by

Cb=Δ/L.B.d1 where Δ is the volume of the molded displacement of the vessel, excluding bossing, in a vessel with a metal shell, and is the volume of displacement to the outer surface of the hull in a vessel with a shell of any other material, both taken at a molded draft of d1; and, d1 is 85 percent of the least molded depth.

(h) Freeboard. The freeboard assigned is the distance measured vertically downward amidships from the upper edge of the deck line to the upper edge of the related load line.

(i) Freeboard deck. (1) The freeboard deck is normally the uppermost complete deck exposed to weather and sea, which has permanent means of closing all openings in the weather part thereof, and below which all openings in the sides of the vessel are fitted with permanent means of watertight closing. In a vessel having a discontinuance freeboard deck, the lowest line of the exposed deck and the continuation of that line parallel to the upper part of the deck is taken as the freeboard deck. At the option of the owner and subject to the approval of the assigning authority a lower deck may be designated as the freeboard deck, provided it is a complete and permanent deck continuous in a fore and aft direction at least between the machinery space and peak bulkheads and continuous athwartships. When this lower deck is stepped the lowest line of the deck and the continuation of that line parallel to the upper part of the deck is taken as the freeboard deck.

(2) When a lower deck is designated as the freeboard deck, that part of the hull which extends above the freeboard deck is treated as a superstructure so far as concerns the application of the conditions of assignment and the calculation of freeboard. It is from this deck that the freeboard is calculated.

(j) Superstructure. (1) A superstructure is a decked structure on the freeboard deck, extending from side to side of the vessel or with the side plating not being inboard of the shell plating more than 4 percent to the breadth. (B). A raised quarter deck is regarded as a superstructure.

(2) An enclosed superstructure is a superstructure with:

(i) Enclosing bulkheads of efficient construction;

(ii) Access openings, if any in these bulkheads fitted with doors complying with the requirements of § 42.15-10; and,

(iii) All other openings in sides or ends of the superstructure fitted with efficient weathertight means of closing.

Note:

A bridge or poop shall not be regarded as enclosed unless access is provided for the crew to reach machinery and other working spaces inside the superstructures by alternative means, which are available at all times when bulkhead openings are closed.

(3) The height of a superstructure is the least vertical height measured at side from the top of the superstructure deck beams to the top of the freeboard deck beams.

(4) The length of a superstructure (S) is the mean length of the part of the superstructure which lies within the length (L).

(k) Flush deck vessel. A flush deck vessel is one which has no superstructure on the freeboard deck.

(l) Weathertight. Weathertight means that in any sea conditions water will not penetrate into the vessel.

[CGFR 68-60, 33 FR 10058, July 12, 1968, as amended by CGFR 68-126, 34 FR 9013, June 5, 1969; 43 FR 31928, July 24, 1978]

(a) The deck line is a horizontal line 12 inches in length and 1 inch in breadth. It shall be marked amidships on each side of the vessel, and its upper edge shall normally pass through the point where the continuation outwards of the upper surface of the freeboard deck intersects the outer surface of the shell (as illustrated in Figure 42.13-20(a)), provided that the deck line may be placed with reference to another fixed point on the vessel on condition that the freeboard is correspondingly corrected. The location of the reference point and the identification of the freeboard deck shall in all cases be indicated on the International Load Line Certificate (1966), and, as applicable, on all other load line certificates issued pursuant to this part 42.

Figure 42.13-20(a)—Deck Line [CGFR 68-60, 33 FR 10059, July 12, 1968, as amended by CGFR 68-126, 34 FR 9014, June 5, 1969]

(a) The load line mark shall consist of a ring 12 inches in outside diameter and 1 inch wide which is intersected by a horizontal line 18 inches in length and 1 inch in breadth, the upper edge of which passes through the center of the ring. The center of the ring shall be placed amidships and at a distance equal to the assigned summer freeboard measured vertically below the upper edge of the deck line (as illustrated in Figure 42.13-25(a)).

Figure 42.13-25(a)—Load line mark and lines to be used with this mark [CGFR 68-60, 33 FR 10059, July 12, 1968]

(a) The lines which indicate the load line assigned in accordance with the regulations in this part shall be horizontal lines 9 inches in length and 1 inch in breadth which extend forward of, unless expressly provided otherwise, and at right angles to, a vertical line 1 inch in breadth marked at a distance 21 inches forward of the center of the ring (as illustrated in Figure 42.13-25(a)).

(b) The following load lines shall be used:

(1) The summer load line indicated by the upper edge of the line which passes through the center of the ring and also by a line marked S.

(2) The winter load line indicated by the upper edge of a line marked W.

(3) The winter North Atlantic load line indicated by the upper edge of a line marked WNA.

(4) The tropical load line indicated by the upper edge of a line marked T.

(5) The fresh water load line in summer indicated by the upper edge of a line marked F. The fresh water load line in summer is marked abaft the vertical line. The difference between the fresh water load line in summer and the summer load line is the allowance to be made for loading in fresh water at the other load lines.

(6) The tropical fresh water load line indicated by the upper edge of a line marked TF, and marked abaft the vertical line.

(c) If timber freeboards are assigned, the timber load lines shall be marked in addition to ordinary load lines. These lines shall be horizontal lines 9 inches in length and 1 inch in breadth which extend abaft unless expressly provided otherwise, and are at right angles to, a vertical line 1 inch in breadth marked at a distance 21 inches abaft the center of the ring (as illustrated in Figure 42.13-30(c)).

Figure 42.13-30(c)—Timber load line mark and lines to be used with this mark

(d) The following timber load lines shall be used:

(1) The summer timber load line indicated by the upper edge of a line marked LS.

(2) The winter timber load line indicated by the upper edge of a line marked LW.

(3) The winter North Atlantic timber load line indicated by the upper edge of a line marked LWNA.

(4) The tropical timber load line indicated by the upper edge of a line marked LT.

(5) The fresh water timber load line in summer indicated by the upper edge of a line marked LF and marked forward of the vertical line.

Note:

The difference between the fresh water timber load line in summer and the summer timber load line is the allowance to be made for loading in fresh water at the other timber load lines.

(6) The tropical fresh water timber load line indicated by the upper edge of a line marked LTF and marked forward of the vertical line.

(e) Where the characteristics of a vessel, or the nature of the vessel's service or navigational limits make any of the seasonal lines inapplicable, these lines may be omitted.

(f) Where a vessel is assigned a greater than minimum freeboard so that the load line is marked at a position corresponding to, or lower than, the lowest seasonal load line assigned at minimum freeboard in accordance with the present Convention, only the fresh water load line need be marked.

(g) On sailing vessels only the fresh water load line and the winter North Atlantic load line need be marked (as illustrated in Figure 42.13-30(g)).

Figure 42.13-30(g)—Load line mark on sailing vessel and lines to be used with this mark

(h) Where a winter North Atlantic load line is identical with the winter load line corresponding to the same vertical line, this load line shall be marked W.

(i) Additional load lines required by other international conventions in force may be marked at right angles to and abaft the vertical line specified in paragraph (a) of this section.

[CGFR 68-60, 33 FR 10059, July 12, 1968, as amended by CGFR 68-126, 34 FR 9014, June 5, 1969]

(a) The mark of the assigning authority by whom the load lines are assigned may be indicated alongside the load line ring above the horizontal line which passes through the center of the ring, or above and below it. This mark shall consist of not more than four initials to identify the assigning authority's name, each measuring approximately 4 1/2 inches in height and 3 inches in width.

[CGspan 68-60, 33 span 10060, July 12, 1968]

(a) The ring, lines and letters shall be painted in white or yellow on a dark ground or in black on a light ground. They shall also be permanently marked on the sides of the vessels to the satisfaction of the assigning authority. The marks shall be plainly visible and, if necessary, special arrangements shall be made for this purpose.

[CGFR 68-60, 33 FR 10060, July 12, 1968, as amended by CGFR 68-126, 34 FR 9014, June 5, 1969]

(a) The International Load Line Certificate (1966) shall not be delivered to the vessel until § 42.07-5 has been fully complied with under the authority and provisions of subparts 42.07 and 42.09 of this part.

[CGFR 68-60, 33 FR 10060, July 12, 1968, as amended by CGFR 68-126, 34 FR 9014, June 5, 1969]