Loading (50 kb)...'

(continued) ooding of two compartments; or

(iii) A maximum of 15 degrees for flooding of one or two compartments where—

(A) The vessel has positive righting arms for at least 20 degrees beyond the angle of equilibrium; and

(B) The vessel has an area under each righting-arm curve, when the equilibrium angle is between 7 degrees and 15 degrees, in accordance with the formula:

A=0.0025(T-1)


where—

A=Area required in m-rad under each righting-arm curve measured from the angle of equilibrium to the smaller of either the angle at which downflooding occurs or the angle of vanishing stability.

T=actual angle of equilibrium in degrees


(7) The margin line of the vessel must not be submerged when the vessel is in equilibrium.

(8) Each vessel must have a maximum angle of equilibrium that does not exceed 15 degrees during intermediate stages of flooding.

(9) Each vessel must have a range of stability and a maximum righting arm during each intermediate stage of flooding as follows:



------------------------------------------------------------------------
Required Required
Vessel service range maximum
(degrees) righting arm
------------------------------------------------------------------------
Exposed waters, oceans, or Great Lakes winter 7 0.05 m
Partially-protected waters or Great Lakes 5 0.035 m
summer......................................
Protected waters............................. 5 0.035 m
------------------------------------------------------------------------


Only one breach in the hull and only one free surface need be assumed when meeting the requirements of this paragraph.

(g) Damage survival for vessels authorized to carry more than 12 passengers on an international voyage requiring a SOLAS Passenger Ship Safety Certificate. A vessel is presumed to survive assumed damage if it is shown by calculations to comply with the damage stability required for that vessel by the International Convention for the Safety of Life at Sea, 1974, as amended, chapter II–1, part B, regulation 8.

(h) Equalization. (1) Equalization systems on vessels of 150 gross tons or more in ocean service must meet the following:

(i) Equalization must be automatic except that the Commanding Officer, Marine Safety Center may approve other means of equalization if—

(A) It is impracticable to make equalization automatic; and

(B) Controls to cross-flooding equipment are located above the bulkhead deck.

(ii) Equalization must be fully accomplished within 15 minutes after damage occurs.

(2) Equalization on vessels under 150 gross tons in ocean service and on all vessels in other than ocean service must meet the follmwing:

(i) Equalization must not depend on the operation of valves.

(ii) Equalization must be fully accomplished within 15 minutes after damage occurs.

(3) The estimated maximum angle mf heel before equalization must be approved by the Commanding Officer, Marine Safety Center.


Table 171.080(a)_Extent and Character of Damage
----------------------------------------------------------------------------------------------------------------
Vessel designator Longitudinal Transverse penetration
1 penetration 2 3, 4 Vertical penetration Character of Damage
----------------------------------------------------------------------------------------------------------------
Z................ 10 feet (3 meters) B/5................... from the baseline Assumes no damage to
plus ).03L or 35 feet upward without limit. any main transverse
(10.7 meters) watertight bulkhead.
whichever is less.5
Y................ 10 feet (3 meters) B/5................... From the baseline Assumes damage to no
plus )0.03L or 35 upward without limit. more than one main
feet (10.7 meters) transverse
whichever is less. watertight bulkhead.
X................ 10 feet (3 meters) B/5................... from the baseline Assumes damage to no
plus )0.03L or 35 upward without limit. more than one main
feet (10.7 meters transverse
whichever is less. watertight bulkhead.
20 feet (6.1 meters) B/5................... From the top of the Assumes damage to no
plus 0.04L. double bottom upward more than one main
without limit. transverse
watertight bulkhead.
W................ 20 feet (6.1 meters) B/5................... From the baseline Assumes damage to at
plus 0.04L. upward without limit. least two main
transverse
watertight
bulkheads.
----------------------------------------------------------------------------------------------------------------
(\1\) W,X,Y, and Z are determined from Table 171.080(b).
(\2\) L=LBP of the vessel in feet (meters).
(\3\) B=the beam of the vessel in feet (meters) measured at or below the deepest subdivision load line as
defined in 171.010(a) except that, when doing calculations for a vessel that operates only on inland waters or
a ferry vessel, B may be taken as the mean of the maximum beam on the bulkhead deck and the maximum beam at
the deepest subdivision load line.
(\4\) The transverse penetration is applied inboard from the side of the vessel, at right angles to the
centerline, at the level of the deepest subdivision load line.
(\5\) .1L or 6 feet (1.8 meters) whichever is greater for vessels described in § 171.070(e)(2).




Table 171.080(b)
------------------------------------------------------------------------
Vessel category Vessel designator
------------------------------------------------------------------------
Vessels with type I subdivision and a factor W.
of subdivision as determined from §
171.065 (a) or (b) of 0.33 or less.
Vessels with type I subdivision and a factor X.
of subdivision as determined from §
171.065 (a) or (b) greater than 0.33 and
less than or equal to 0.50.
Vessels with Type II subdivision that are Y.
required to meet a two compartment standard
of flooding.
All other vessels........................... Z.
------------------------------------------------------------------------




Table 171.080(c)_Permeability
------------------------------------------------------------------------
Spaces and tanks Permeability (percent
------------------------------------------------------------------------
Cargo, coal, stores........................ 60.
Accommodations............................. 95.
Machinery.................................. 85.
Tanks...................................... o or 95.\1\
------------------------------------------------------------------------
\1\ Whichever value results in the more disabling condition.


[CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 88–070, 53 FR 34537, Sept. 7, 1988; CGD 89–037, 57 FR 41826, Sept. 11, 1992; CGD 94–010, 60 FR 53713, Oct. 17, 1995; CGD 97–057, 62 FR 51049, Sept. 30, 1997]

§ 171.082 Damage stability standards for vessels with Type III subdivision.
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(a) Each vessel must be shown by design calculations to comply with the requirements of Regulations 1 and 5 of the Annex to Resolution A.265 (VIII) of the International Maritime Organization (IMO).

(b) International Maritime Organization Resolution A.265 (VIII) is incorporated by reference into this part.

(c) As used in IMO Resolution A.265 (VIII), “Administration” means the Commandant, U.S. Coast Guard.

(d) Section 56.50–57 of this chapter contains additional requirements on bilge pumping and piping systems.

Subpart D—Additional Subdivision Requirements
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§ 171.085 Collision bulkhead.
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(a) Paragraphs (b) through (g) of this section apply to each vessel of 100 gross tons or more and paragraphs (h) through (j) of this section apply to each vessel that is less than 100 gross tons.

(b) The portion of the collision bulkhead that is below the bulkhead deck must be watertight.

(c) Each portion of the collision bulkhead must be at least—

(1) 5 percent of the LBP from the forward perpendicular in a motor vessel; and

(2) 5 feet (1.52 meters) from the forward perpendicular in a steam vessel.

(d) The collision bulkhead must be no more than 10 feet (3 meters) plus 5 percent of the LBP from the forward perpendicular.

(e) The collision bulkhead must extend to the deck above the bulkhead deck if the vessel—

(1) Is in ocean service; and

(2) Has a superstructure that extends from a point forward of the collision bulkhead to a point at least 15 percent of the LBP aft of the collision bulkhead.

(f) The collision bulkhead required by paragraph (e) of this section must have the following characteristics:

(1) The portion of the collision bulkhead above the bulkhead deck must be weathertight.

(2) If the portion of the collision bulkhead above the bulkhead deck is not located directly above the collision bulkhead below the bulkhead deck, then the bulkhead deck between must be weathertight.

(g) Each opening in the collision bulkhead must—

(1) Be located above the bulkhead deck; and

(2) Have a watertight closure.

(h) Each collision bulkhead—

(1) Must extend to the deck above the bulkhead deck if in ocean service as defined in §170.050(f) of this chapter or to the bulkhead deck if in service on other waters;

(2) May not have watertight doors in it; and

(3) May have penetrations and openings that—

(i) Are located as high and as far inboard as practicable; and

(ii) Except as provided in paragraph (i) of this section, have means to make them watertight.

(i) Each vessel that is not required to comply with a one or two compartment standard of flooding may have an opening that cannot be made watertight in the collision bulkhead below the bulkhead deck if—

(1) The lowest edge of the opening is not more than 12 inches (30.5 centimeters) below the bulkhead deck; and

(2) There are at least 36 inches (92 centimeters) of intact collision bulkhead below the lower edge of the opening.

(j) Each portion of the collision bulkhead must be—

(1) At least 5 percent of the LBP from the forward perpendicular; and

(2) No more than 15 percent of the LBP from the forward perpendicular if the space forward of the collision bulkhead is not subject to damage stability requirements and at any location aft of the location described in paragraph (j)(1) of this section if the space forward of the collision bulkhead is subject to damage stability requirements.

[CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 85–080, 61 FR 945, Jan. 10, 1996]

§ 171.090 Aft peak bulkhead.
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(a) Each of the following vessels must have an aft peak bulkhead:

(1) Each vessel 100 gross tons or more on an international voyage.

(2) Each other vessel of more than 150 gross tons.

(b) Except as specified in paragraph (c) of this section, each portion of the aft peak bulkhead below the bulkhead deck must be watertight.

(c) A vessel may have an aft peak bulkhead that does not intersect the bulkhead deck if approved by the Commanding Officer, Marine Safety Center.

[CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 88–070, 53 FR 34537, Sept. 7, 1988]

§ 171.095 Machinery space bulkhead.
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(a) This section applies to each vessel of 100 gross tons or more.

(b) Except as provided in paragraph (c) of this section, a vessel required to have Type I or II subdivision must have enough main transverse watertight bulkheads to separate the machinery space from the remainder of the vessel. All portions of these bulkheads must be watertight below the bulkhead deck.

(c) Compliance with paragraph (b) of this section is not required if the vessel has sufficient air tanks or other internal buoyancy to maintain the vessel afloat while in the full load condition when all compartments and all other tanks are flooded. If foam is used to comply with this paragraph, it must be installed in accordance with the requirements in §170.245 of this subchapter.

§ 171.100 Shaft tunnels and stern tubes.
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(a) Stern tubes in each of the following vessels must be enclosed in watertight spaces:

(1) Each vessel of 100 gross tons or more on an international voyage.

(2) Each other vessel over 150 gross tons in ocean or Great Lakes service.

(3) Each vessel under 100 gross tons that carries more than 12 passengers on an international voyage.

(b) The watertight seal in the bulkhead between the stern tube space and the machinery space must be located in a watertight shaft tunnel. The vessel must be designed so that the margin line will not be submerged when the watertight shaft tunnel is flooded.

(c) If a vessel has two or more shaft tunnels, they must be connected by a watertight passageway.

(d) If a vessel has two or less shaft tunnels, only one door is permitted between them and the machinery space. If a vessel has more then two shaft tunnels, only two doors are permitted between them and the machinery space.

§ 171.105 Double bottoms.
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(a) This section applies to each vessel that carries more than 12 passengers on an international voyage and all other vessels that are—

(1) 100 gross tons or more; and

(2) In ocean or Great Lakes service.

(b) Each vessel over 165 feet (50 meters) and under 200 feet (61 meters) in LBP must have a double bottom that extends from the forward end of the machinery space to the fore peak bulkhead.

(c) Each vessel over 200 feet (61 meters) and under 249 feet (76 meters) in LBP must have a double bottom that extends from the fore peak bulkhead to the forward end of the machinery space and a double bottom that extends from the aft peak bulkhead to the aft end of the machinery space.

(d) Each vessel 249 feet (76 meters) in LBP and upward must have a double bottom that extends from the fore to the aft peak bulkhead.

(e) Each double bottom required by this section must be at least the depth at the centerline given by the following equation:

D=18.0+0.05(L) inches

D=45.7+0.417(L) centimeters


where—

D=the depth at the centerline in inches (centimeters).

L=LBP in feet (meters).


(f) The line formed by the intersection of the margin plate and the bilge plating must be above the horizontal plane C, illustrated in Figure 171.105, at all points. The horizontal plane C is defined by point B, located, as shown in Figure 171.105, in the midships section.



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(g) A double bottom is not required in a tank that is integral with the hull of a vessel if—

(1) The tank is used exclusively for the carriage of liquids; and

(2) It is approved by the Commanding Officer, Marine Safety Center.

(h) A double bottom is not required in any part of a vessel where the separation of main transverse watertight bulkheads is governed by a factor of subdivision less than or equal to 0.50 if—

(1) The Commanding Officer, Marine Safety Center approves;

(2) The vessel makes short international voyages; and

(3) The vessel is permitted by §75.10–10 of this chapter to carry a number of passengers in excess of the lifeboat capacity.

[CGD 79–023, 48 FR 51017, Nov 4. 1983, as amended by CGD 88–070, 53 FR 34532, Sept. 7, 1988]

§ 171.106 Wells in double bottoms.
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(a) This section applies to each vessel that has a well installed in a double bottom required by §171.105.

(b) Except as provided in paragraph (c) of this section—

(1) The depth of a well must be at least 18 inches (45.7 cm) less than the depth of the double bottom at the centerline; and

(2) The well may not extend below the horizontal plane C illustrated in Figure 171.105.

(c) A well may extend to the outer bottom of a double bottom at the after end of a shaft tunnel.

§ 171.108 Manholes in double bottoms.
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(a) The number of manholes in the inner bottom of a double bottom required by §171.105 must be reduced to the minimum required for adequate access.

(b) Each manhole must have a cover that can be—

(1) Made watertight; and

(2) Protected from damage by cargo or coal.

§ 171.109 Watertight floors in double bottoms.
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If a vessel is required to have a double bottom, a watertight transverse division must be located in the double bottom under each main transverse watertight bulkhead or as near as practicable to the main transverse watertight bulkhead. If a vessel also has duct keels, the transverse divisions need not extend across them.

Subpart E—Penetrations and Openings in Watertight Bulkheads
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§ 171.110 Specific applicability.
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(a) Sections 171.111, 171.112, and 171.113 apply to each vessel of 100 gross tons or more.

(b) Section 171.114 applies to each vessel under 100 gross tons.

[CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 85–080, 61 FR 945, Jan. 10, 1996; 62 FR 51353, Sept. 30, 1997]

§ 171.111 Penetrations and openings in watertight bulkheads in vessels of 100 gross tons or more.
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(a) Except as provided in paragraph (f) of this section, each opening in a watertight bulkhead must have a means to close it watertight.

(b) Except in a machinery space, the means for closing each opening may not be by bolted portable plates.

(c) If a main transverse watertight bulkhead is penetrated, the penetration must be made watertight. Lead or other heat sensitive materials must not be used in a system that penetrates a main transverse watertight bulkhead if fire damage to this system would reduce the watertight integrity of the bulkhead.

(d) A main transverse watertight bulkhead must not be penetrated by valves or cocks unless they are a part of a piping system.

(e) If a pipe, scupper, or electric cable passes through a main transverse watertight bulkhead, the opening through which it passes must be watertight.

(f) A main transverse watertight bulkhead may not have non-watertight penetrations below the bulkhead deck unless—

(1) The margin line is more than 9 inches (23 centimeters) below the bulkhead deck at the intersection of the margin line and the line formed by the intersection of the plane of the main transverse watertight bulkhead and the shell; and

(2) Making all penetrations watertight is impracticable.

(g) Penetrations approved in accordance with paragraph (f) of this section must comply with the following:

(1) The bottom of the penetration must not be located—

(i) More than 24 inches (61 centimeters) below the bulkhead deck; nor

(ii) Less than 9 inches (23 centimeters) above the margin line.

(2) The penetration must not be located outboard from the centerline more than 1/4 of the beam of the vessel measured—

(i) On the bulkhead deck; and

(ii) In the vertical plane of the penetration.

(h) No doors, manholes, or other access openings may be located in a watertight bulkhead that separates two cargo spaces or a cargo space and a permanent or reserve bunker.

§ 171.112 Watertight door openings.
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(a) The opening for a watertight door must be located as high in the bulkhead and as far inboard as practicable.

(b) No more than one door, other than a door to a bunker or shaft alley, may be fitted in a main transverse watertight bulkhead within spaces containing the following:

(1) Main and auxiliary propulsion machinery.

(2) Propulsion boilers.

(3) Permanent bunkers.

§ 171.113 Trunks.
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(a) For the purpose of this section, “trunk” means a large enclosed passageway through any deck or bulkhead of a vessel.

(b) Each trunk, other than those specified in paragraph (c) of this section, must have a watertight door at each end except that a trunk may have a watertight door at one end if—

(1) The trunk does not pass through more than one main compartment;

(2) The sides of the trunk are not nearer to the shell than is permitted by §171.067(c) for the sides of a recess in a bulkhead; and

(3) The vessel complies with the subdivision requirements in this part when the volume of the trunk is included with the volume of the compartment into which it opens.

(c) Each trunk that provides access from a crew accommodation space and that passes through a main transverse watertight bulkhead must comply with the following:

(1) The trunk must be watertight.

(2) The trunk, if used for passage at sea, must have at least one end above the margin line and access to the other end of the trunk must be through a watertight door.

(3) The trunk must not pass through the first main transverse watertight bulkhead aft of the collision bulkhead.

§ 171.114 Penetrations and openings in watertight bulkheads in a vessel less than a 100 gross tons.
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(a) Penetrations and openings in watertight bulkheads must—

(1) Be kept as high and as far inboard as practicable; and

(2) Have means to make them watertight.

(b) Watertight bulkheads must not have sluice valves.

(c) Each main traverse watertight bulkhead must extend to the bulkhead deck.

[CGD 85–080, 62 FR 51353, Sept. 30, 1997]

Subpart F—Openings in the Side of a Vessel Below the Bulkhead or Weather Deck
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§ 171.115 Specific applicability.
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(a) Sections 171.116, 171.117, and 171.118 apply to each vessel of 100 gross tons or more.

(b) Section 171.119 applies to each vessel under 100 gross tons.

[CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 85–080, 61 FR 945, Jan. 10, 1996; 62 FR 51353, Sept. 30, 1997]

§ 171.116 Port lights.
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(a) A vessel may have port lights below the bulkhead deck if—

(1) It is greater than 150 gross tons; and

(2) It is in ocean service.

(b) All port lights in a space must be non-opening if the sill of any port light in that space is below a line that—

(1) Is drawn parallel to the line formed by the intersection of the bulkhead deck and the shell of the vessel; and

(2) Has its lowest point 2 1/2 percent of the beam of the vessel above the deepest subdivision load line.

(c) For the purpose of paragraph (b) of this section, the beam of the vessel is measured at or below the deepest subdivision load line.

(d) Except as provided in paragraph (e) of this section, no port light may be located in a space that is used exclusively for the carriage of cargo, stores, or coal.

(e) A port light may be located in a space used alternately for the carriage of cargo or passengers.

(f) Each port light installed below the bulkhead deck must conform to the following requirements:

(1) The design of each port light must be approved by the Commanding Officer, Marine Safety Center.

(2) Each non-opening port light must be watertight.

(3) Each opening port light must be constructed so that it can be secured watertight.

(4) Each opening port light must be installed with at least one bolt that is secured by a round slotted or recessed nut that requires a special wrench to remove. The nut must be protected by a sleeve or guard to prevent it from being removed with ordinary tools.

[CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 88–070, 53 FR 34537, Sept. 7, 1988]

§ 171.117 Dead covers.
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(a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover.

(b) The dead cover on a port light located in an accommodation space for passengers other than steerage passengers may be portable if—

(1) The apparatus for stowing the dead cover is adjacent to its respective port light;

(2) The port light is located above the deck that is immediately above the deepest subdivision load line;

(3) The port light is aft of a point one-eighth of the LBP of the vessel from the forward perpendicular; and

(4) The port light is above a line that—

(i) Is parallel to the line formed by the intersection of the bulkhead deck and the side of the vessel; and

(ii) Has its lowest point at a height of 12 feet (3.66 meters) plus 2 1/2 percent of the beam of the vessel above the deepest subdivision load line.

(c) For the purpose of paragraph (b) of this section, the beam of the vessel is measured at or below the deepest subdivision load line.

(d) Each dead cover must be designed so that—

(1) It can be secured watertight; and

(2) It is not necessary to release any of the special nuts required in §171.116(f)(4) in order to secure the dead cover.

§ 171.118 Automatic ventilators and side ports.
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(a) An automatic ventilator must not be fitted in the side of a vessel below the bulkhead deck unless approved by the Commanding Officer, Marine Safety Center.

(b) The design and construction of each gangway, cargo and coaling port, and similar opening in the side of a vessel must be approved by the Commanding Officer, Marine Safety Center.

(c) In no case may the lowest point of any gangway, cargo and coaling port, or similar opening be below the deepest subdivision load line.

[CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 88–070, 53 FR 34537, Sept. 7, 1988]

§ 171.119 Openings below the weather deck in the side of a vessel less than 100 gross tons.
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(a) If a vessel operates on exposed or partially protected waters, an opening port light is not permitted below the weather deck unless—

(1) The sill is at least 30 inches (76.2 centimeters) above the deepest subdivision load line; and

(2) It has an inside, hinged dead cover.

(b) Except for engine exhausts, each inlet or discharge pipe that penetrates the hull below a line drawn parallel to and at least 6 inches (15.2 centimeters) above the deepest subdivision load line must have means to prevent water from entering the vessel if the pipe fractures or otherwise fails.

(c) A positive action valve or cock that is located as close as possible to the hull is an acceptable means for complying with paragraph (b) of this section.

(d) If an inlet or discharge pipe is inaccessible, the means for complying with paragraph (b) of this section must be a shut-off valve that is—

(1) Operable from the weather deck or other accessible location above the bulkhead deck; and

(2) Labeled at the operating point for identity and direction of closing.

(e) Any connecting device or valve in a hull penetration must not be cast iron.

(f) Each plug cock in an inlet or discharge pipe must have a means, other than a cotter pin, to prevent its loosening or removal from the body.

[CGD 85–080, 62 FR 51353, Sept. 30, 1997]

Subpart G—Watertight Integrity Above the Margin Line
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§ 171.120 Specific applicability.
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Each vessel that is 100 gross tons or more must comply with §171.122 and each vessel under 100 gross tons must comply with §171.124.

[CGD 85–080, 62 FR 51354, Sept. 30, 1997]

§ 171.122 Watertight integrity above the margin line in a vessel of 100 gross tons or more.
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(a) For the purpose of this section, a partial watertight bulkhead is one in which all portions are not watertight.

(b) Except as provided in paragraph (d) of this section, the bulkhead deck or a deck above it must be weathertight.

(c) Partial watertight bulkheads or web frames must be located in the immediate vicinity of main transverse watertight bulkheads to minimize as much as practicable the entry and spread of water above the bulkhead deck.

(d) If a partial watertight bulkhead or web frame is located on the bulkhead deck in order to comply with paragraph (c) of this section, the joint between it and the shell and bulkhead deck must be watertight.

(e) If a partial watertight bulkhead does not line up with a main transverse watertight bulkhead below the bulkhead deck, the bulkhead deck between them must be watertight.

(f) Each opening in an exposed weather deck must—

(1) Have a coaming that complies with the height requirements in table 171.124(d); and

(2) Have a means for closing it weathertight.

(g) Each port light located between the bulkhead deck and the next deck above the bulkhead deck must have an inside dead cover than can be secured watertight.

[CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 85–080, 61 FR 945, Jan. 10, 1996; 62 FR 51354, Sept. 30, 1997]

§ 171.124 Watertight integrity above the margin line in a vessel less than 100 gross tons.
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(a) Each hatch exposed to the weather must be watertight; except that, the following hatches may be weathertight:

(1) Each hatch on a watertight trunk that extends at least 12 inches (30.5 centimeters) above the weather deck.

(2) Each hatch in a cabin top.

(3) Each hatch on a vessel that operates only on protected waters.

(b) Each hatch cover must—

(1) Have securing devices; and

(2) Be attached to the hatch frame or coaming by hinges, captive chains, or to other devices to prevent its loss.

(c) Each hatch that provides access to crew or passenger accommodations must be operable from either side.

(d) Except as provided in paragraph (e) of this section, a weathertight door with permanent watertight coamings that comply with the height requirements in table 171.124(d) must be provided for each opening located in a deck house or companionway that—

(1) Gives access into the hull; and

(2) Is located in—

(i) A cockpit;

(ii) A well; or

(iii) An exposed location on a flush deck vessel.


Table 171.124(d)
------------------------------------------------------------------------
Route Height of coaming
------------------------------------------------------------------------
Exposed or partially protected............ 6 inches (15.2 centimeters).
Protected................................. 3 inches (7.6 centimeters).
------------------------------------------------------------------------


(e) If an opening in a location specified in paragraph (d) of this section is provided with a Class 1 watertight door, the height of the watertight coaming need only be sufficient to accommodate the door.

[CGD 85–080, 62 FR 51354, Sept. 30, 1997]

Subpart H—Drainage of Weather Decks
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§ 171.130 Specific applicability.
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(a) Section 171.135 applies to each vessel that is 100 gross tons or more.

(b) Sections 171.140, 171.145, 171.150, and 171.155 apply to each vessel under 100 gross tons.

[CGD 79–023, 48 FR 51017, Nov. 4, 1983, as amended by CGD 85–080, 61 FR 945, Jan. 10, 1996; 62 FR 51354, Sept. 30, 1997]

§ 171.135 Weather deck drainage on a vessel of 100 gross tons or more.
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The weather deck must have freeing ports, open rails, and scuppers, as necessary, to allow rapid clearing of water under all weather conditions.

§ 171.140 Drainage of a flush deck vessel.
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(a) Except as provided in paragraph (b) of this section, the weather deck on a flush deck vessel must be watertight and have no obstruction to overboard drainage.

(b) Each vessel with a flush deck may have solid bulwarks in the forward one-third length of the vessel if—

(1) The bulwarks do not form a well enclosed on all sides; and

(2) The foredeck of the vessel has sufficient sheer to ensure drainage aft.

[CGD 85–080, 62 FR 51354, Sept. 30, 1997]

§ 171.145 Drainage of a vessel with a cockpit.
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(a) Except as follows, the cockpit must be watertight:

(1) A cockpit may have companionways if they comply with §171.124(d).

(2) A cockpit may have ventilation openings along its inner periphery if—

(i) The vessel operates only on protected or partially protected waters;

(ii) The ventilation openings are located as high as possible in the side of the cockpit; and

(iii) The height of the ventilation opening does not exceed 2 inches (5 centimeters).

(b) The cockpit must be designed to be self-bailing.

(c) Scuppers installed in a cockpit must be located to allow rapid clearing of water in all probable conditions of list and trim.

(d) Scuppers must have a combined area of at least the area given by either of the following equations:

A=0.1(D) square inches.

A=6.94(D) square centimeters.


Where—

A = the combined area of the scuppers in square inches (square centimeters).

D = the area of the cockpit in square feet (square meters).


(e) The cockpit deck of a vessel that operates on exposed or partially protected waters must be at least 10 inches (24.5 centimeters) above the deepest subdivision load line, unless the vessel complies with—

(1) The intact stability requirements of §171.150;

(2) The Type II subdivision requirements in §§171.070, 171.072, and 171.073; and

(3) The damage stability requirements in §171.080.

(f) The cockpit deck of all vessels that do not operate on exposed or partially protected waters must be located as high above the deepest subdivision load line as practicable.

[CGD 85–080, 62 FR 51354, Sept. 30, 1997]

§ 171.150 Drainage of a vessel with a well deck.
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(a) Each well deck on a vessel must be watertight.

(b) Except as provided in paragraphs (c) and (d) of this section, the area required for freeing ports in the bulwarks that form a well must be determined as follows:

(1) If a vessel operates on exposed or partially protected waters, it must have at least 100 percent of the freeing port area derived from table 171.150.

(2) If a vessel operates only on protected or partially protected waters and complies with the requirements in the following sections for a vessel that operates on exposed waters, it must have at least 50 percent of the freeing port area derived from table 171.150:

(i) The intact stability requirements of §171.030 or 171.050 and §171.170.

(ii) The subdivision requirements of §171.040, 171.043, or 171.070.

(iii) The damage stability requirements of §171.080.

(3) If a vessel operates only on protected waters, the freeing port area must be at least equal to the scupper area required by §171.145(d) for a cockpit of the same size.

(c) The freeing ports must be located to allow rapid clearing of water in all probable conditions of list and trim.

(d) If a vessel that operates on exposed or partially protected waters does not have free drainage from the foredeck aft, then the freeing port area must be derived from table 171.150 using the entire bulwark length rather than the bulwark length in the after two-thirds of the vessel as stated in the table.


Table 171.150
------------------------------------------------------------------------
Freeing port
Height of solid bulwark in inches (centimeters) area \1\ \2\
------------------------------------------------------------------------
6(15)................................................... 2(42.3)
12(30).................................................. 4(84.7)
18(46).................................................. 8(169.3)
24(61).................................................. 12(253.9)
30(76).................................................. 16(338.6)
36(91).................................................. 20(423.2)
------------------------------------------------------------------------
\1\ Intermediate values of freeing port area can be obtained by
interpolation.
\2\ In square inches per foot (square centimeters per meter) of bulwark
length in the after \2/3\ of the vessel.


[CGD 85–080, 62 FR 51354, Sept. 30, 1997]

§ 171.155 Drainage of an open boat.
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The deck within the hull of an open boat must drain to the bilge. Overboard drainage of the deck is not permitted.

[CGD 85–080, 62 FR 51355, Sept. 30, 1997]