46 C.F.R. Subpart A—General
Title 46 - Shipping
(a) This part applies to passenger vessels inspected under subchapter K or H of this chapter. (b) Specific sections of this part also apply to nautical school ships, sailing school vessels and oceanographic vessels. The applicable sections are listed in subparts C and D of part 173 of this chapter. [CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 83–005, 51 FR 923, Jan. 9, 1986; CGD 95–012, 60 FR 48052, Sept. 18, 1995; 60 FR 50120, Sept. 28, 1995; CGD 85–080, 61 FR 944, Jan. 10, 1996] (a) Cockpit means an exposed recess in the weather deck extending no more than one-half of the vessel's length over deck (LOD) measured over the weather deck. (b) Deepest subdivision load line means the waterline that corresponds to the deepest draft permitted by the applicable subdivision requirements in this part. (c) Equivalent plane bulkhead means a bulkhead that is— (1) Used in lieu of a recessed or stepped bulkhead when doing the subdivision calculations required in this part; and (2) Located as shown in Figure 171.010(a). (d) Ferry means a vessel that— (1) Operates in other than ocean or coastwise service; (2) Has provisions only for deck passengers or vehicles, or both; (3) Operates on a short run on a frequent schedule between two points over the most direct water route; (4) Offers a public service of a type normally attributed to a bridge or tunnel. (e) Freeing port means any direct opening through the vessel's bulwark or hull to quickly drain overboard water which has been shipped on exposed decks. (f) Floodable length means the length of a shell to shell segment of the vessel that, when flooded, will sink and trim the vessel until the margin line is tangent to the waterline. (g) Flush deck means a continuous weather deck located at the uppermost sheer line of the hull. (h) International voyage has the same meaning provided for the term in §70.05–10 of this chapter. (i) Machinery space means, unless otherwise prescribed by the Commandant for unusual arrangements, the space extending from the molded base line to the margin line and between the main transverse watertight bulkheads bounding the following spaces: (1) Each space containing main and auxiliary propelling machinery. (2) Each space containing propulsion boilers. (3) Each space containing permanent coal bunkers. (j) Open boat means a vessel not protected from entry of water by means of a complete deck, or by a combination of a partial weather deck and superstructure which is seaworthy for the waters upon which the vessel operates. (k) Passenger space means a space which is provided for the accommodation and use of passengers, other than a baggage, store, provision or mail room. (l) Recessed bulkhead means a bulkhead that is recessed as shown by bulkhead B in Figure 171.010(b). (m) Small passenger vessel means a vessel of less than 100 gross tons— (1) Carrying more than 6 passengers, including at least one passenger for hire; (2) That is chartered with the crew provided or specified by the owner or owner's representative and carrying more than 6 passengers; (3) That is chartered with no crew provided or specified by the owner or owner's representative and carrying more than 12 passengers; or (4) That is a submersible vessel carrying at least one passenger for hire. (n) Short international voyage means an international voyage where— (1) A vessel is not more than 200 nautical miles (370 kilometers) from a port or place in which the passengers and crew could be placed in safety; and (2) The total distance between the last port of call in the country in which the voyage began and the final port of destination does not exceed 600 nautical miles (1111 kilometers). (o) Scupper means a pipe or tube of at least 30 millimeters (1.25 inches) in diameter leading down from a deck or sole and through the hull to drain water overboard. (p) Stepped bulkhead means a bulkhead that is stepped as shown by bulkhead A in Figure 171.010(b). (q) Well deck means a weather deck fitted with solid bulwarks that impede the drainage of water over the sides or an exposed recess in the weather deck extending one-half or more of the length of the vessel (LOD) measured over the weather deck. [CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 85–080, 61 FR 944, Jan. 10, 1996] (a) A vessel with a continuous bulkhead deck and sufficient sheer. If the average value of the sheer at the forward perpendicular (FP) and the after perpendicular (AP) is at least 12 inches (30.5 cm), the margin line must be located no less than 3 inches (7.6 cm) below the upper surface of the bulkhead deck at side as illustrated in Figure 171.015(a). (b) A vessel with a continuous bulkhead deck and insufficient sheer. If the average value of the sheer at the forward perpendicular (FP) and the after perpendicular (AP) is less than 12 inches (30.5 cm), the margin line must be a parabolic curve with the following characteristics: (1) The parabolic curve must be at least 3 inches (7.6 cm) below the upper surface of the bulkhead deck at the FP and AP. (2) The parabolic curve must be at least the distance given in Table 171.015 below the surface of the bulkhead deck amidships. (3) Intermediate values not shown in Table 171.015 must be interpolated. (4) Figure 171.015(b) illustrates a margin line drawn in this manner. (c) A vessel with a discontinuous bulkhead deck. A continuous margin line must be drawn that is no more than 3 inches (7.6 cm) below the upper surface of the bulkhead deck at side as illustrated in Figure 171.015(c). (d) A vessel with a discontinuous bulkhead deck where the side shell is carried watertight to a higher deck. A continuous margin line must be drawn as illustrated in Figure 171.015(d). (a) One compartment standard of flooding. A vessel is designed to a one compartment standard of flooding if the margin line is not submerged when the total buoyancy between each set of two adjacent main transverse watertight bulkheads is lost. (b) Two compartment standard of flooding. A vessel is designed to a two compartment standard of flooding if the margin line is not submerged when the total buoyancy between each set of three adjacent main transverse watertight bulkheads is lost.
Title 46: Shipping
PART 171—SPECIAL RULES PERTAINING TO VESSELS CARRYING PASSENGERS
Subpart A—General
§ 171.001 Applicability.
§ 171.010 Definitions.
§ 171.015 Location of margin line.
Table 171.015------------------------------------------------------------------------ Required position of Average value of sheer at FP and AP in inches margin line below top of (cm) deck amidships in inches (cm)------------------------------------------------------------------------12 (30.5)..................................... 3 (7.6)6 (15.2)...................................... 6 (15.2)0............................................. 9 (22.8)------------------------------------------------------------------------
§ 171.017 One and two compartment standards of flooding.
