Loading (50 kb)...'

(continued)

(b) Except as otherwise provided in these regulations, the height of the sills of access openings in bulkheads at ends of enclosed superstructures shall be at least 15 inches above the deck.

[CGFR 68–60, 33 FR 10060, July 12, 1968]

§ 42.15-15 Positions of hatchways, doorways and ventilators.
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(a) For the purpose of this part two positions of hatchways, doorways and ventilators are defined as follows:

(1) Position 1: Upon exposed freeboard and raised quarter decks, and upon exposed superstructure decks situated forward of a point located a quarter of the vessel's length from the forward perpendicular.

(2) Position 2: Upon exposed superstructure decks situated abaft a quarter of the vessel's length from the forward perpendicular.

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

§ 42.15-20 Cargo and other hatchways.
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(a) The construction and the means for securing the weathertightness of cargo and other hatchways in positions 1 and 2 shall be at least equivalent to the requirements of §§42.15–25 and 42.15–30.

(b) Coamings and hatchway covers to exposed hatchways on decks above the superstructure deck shall comply with the requirements of the assigning authority.

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

§ 42.15-25 Hatchways closed by portable covers and secured weathertight by tarpaulins and battening devices.
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(a) Hatchway coamings. (1) The coamings of hatchways closed by portable covers secured weathertight by tarpaulins and battening devices shall be of substantial construction, and their height above the deck shall be at least as follows:

(i) 23 1/2 inches if in position 1.

(ii) 17 1/2 inches if in position 2.

(b) Hatchway covers. (1) The width of each bearing surface for hatchway covers shall be at least 2 1/2 inches.

(2) Where covers are made of wood, the finished thickness shall be at least 2 3/8 inches in association with a span of not more than 4.9 feet.

(3) Where covers are made of mild steel, the strength shall be calculated with assumed loads not less than 358 pounds per square foot on hatchways in position 1, and not less than 266 pounds per square foot on hatchways in position 2, and the product of the maximum stress thus calculated and the factor 4.25 shall not exceed the minimum ultimate strength of the material. They shall be so designed as to limit the deflection to not more than 0.0028 times the span under these loads.

(4) The assumed loads on hatchways in position 1 may be reduced to 205 pounds per square foot for vessels of 79 feet in length and shall be not less than 358 pounds per square foot for vessels of 328 feet in length. The corresponding loads on hatchways in position 2 may be reduced to 154 pounds per square foot and 266 pounds per square foot respectively. In all cases values at intermediate lengths shall be obtained by linear interpolation.

(c) Portable beams. (1) Where portable beams for supporting hatchway covers are made of mild steel the strength shall be calculated with assumed loads not less than 358 pounds per square foot on hatchways in position 1 and not less than 266 pounds per square foot on hatchways in position 2 and the product of the maximum stress thus calculated and the factor 5 shall not exceed the minimum ultimate strength of the material. They shall be so designed as to limit the deflection to not more than 0.0022 times the span under these loads. For vessels of not more than 328 feet in length the requirements of paragraph (b)(4) of this section are applicable.

(d) Pontoon covers. (1) Where pontoon covers used in place of portable beams and covers are made of mild steel the strength shall be calculated with the assumed loads given in paragraph (b)(3) of this section, and the product of the maximum stress thus calculated and the factor 5 shall not exceed the minimum ultimate strength of the material. They shall be so designed as to limit the deflection to not more than 0.0022 times the span. Mild steel plating forming the tops of covers shall be not less in thickness than 1 percent of the spacing of stiffeners or 0.24 inches if that be greater. For vessels of not more than 328 feet in length the requirements of paragraph (b)(4) of this section are applicable.

(2) The strength and stiffness of covers made of materials other than mild steel shall be equivalent to those of mild steel to the satisfaction of the assigning authority.

(e) Carriers or sockets. (1) Carriers or sockets for portable beams shall be of substantial construction, and shall provide means for the efficient fitting and securing of the beams. Where rolling types of beams are use, the arrangements shall ensure that the beams remain properly in position when the hatchway is closed.

(f) Cleats. (1) Cleats shall be set to fit the taper of the wedges. They shall be at least 2 1/2 inches wide and spaced not more than 23 1/2 inches center to center; the cleats along each side or end shall be not more than 6 inches from the hatch corners.

(g) Battens and wedges. (1) Battens and wedges shall be efficient and in good condition. Wedges shall be of tough wood or other equivalent material. They shall have a taper of not more than 1 in 6 and shall be not less than 1/2-inch thick at the toes.

(h) Tarpaulins. (1) At least two layers of tarpaulin in good condition shall be provided for each hatchway in positions 1 and 2.

(2) The tarpaulins shall be waterproof and of ample strength. They shall be of a material of at least a standard weight and quality as approved by the assigning and issuing authority.

(i) Security of hatchway covers. (1) For all hatchways in position 1 or 2, steel bars or other equivalent means shall be provided in order efficiently and independently to secure each section of hatchway covers after the tarpaulins are battened down. Hatchway covers of more than 4.9 feet in length shall be secured by at least two such securing appliances.

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

§ 42.15-30 Hatchways closed by weathertight covers of steel or other equivalent material fitted with gaskets and clamping devices.
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(a) Hatchway coamings. At positions 1 and 2 the height above the deck of hatchway coamings fitted with weathertight hatch covers of steel or other equivalent material fitted with gaskets and clamping devices shall be as specified in §42.15–25(a)(1). The height of these coamings may be reduced, or the coamings omitted entirely, on condition that the assigning authority is satisfied that the safety of the vessel is not thereby impaired in any sea conditions. Where coamings are provided they shall be of substantial construction.

(b) Weathertight covers. (1) Where weathertight covers are of mild steel the strength shall be calculated with assumed loads not less than 358 pounds per square foot on hatchways in position 1, and not less than 255 pounds per square foot on hatchways in position 2, and the product of the maximum stress thus calculated and the factor of 4.25 shall not exceed the minimum ultimate strength of the material. They shall be so designed as to limit the deflection to not more than 0.0028 times the span under these loads. Mild steel plating forming the tops of covers shall be not less in thickness than one percent of the spacing of stiffeners or 0.24 inches if that be greater. The provisions of §42.15–25(b)(4) are applicable for vessels of not more than 328 feet in length.

(2) The strength and stiffness of covers made of materials other than mild steel shall be equivalent to those of mild steel to the satisfaction of the assigning authority.

(c) Means for securing weathertightness. (1) The means for securing and maintaining weathertightness shall be to the satisfaction of the assigning authority.

(2) The arrangements shall ensure that the tightness can be maintained in any sea conditions. For this purpose tests for tightness shall be required at the initial surveys, and may be required at periodical surveys and at annual surveys or at more frequent intervals.

[CGFR 68–60, 33 FR 10061, July 12, 1968, as amended by CGFR 68–126, 34 FR 9014, June 5, 1969]

§ 42.15-35 Machinery space openings.
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(a) Machinery space openings in position 1 or 2 shall be properly framed and efficiently enclosed by steel casings of ample strength, and where the casings are not protected by other structures their strength shall be specifically considered. Access openings in such casings shall be fitted with doors complying with the requirements of §42.15–10(a), the sills of which shall be at least 23 1/2 inches above the deck if in position 1, and at least 15 inches above the deck if in position 2. Other openings in such casings shall be fitted with equivalent covers, permanently attached in their proper positions.

(b) Coamings of any fiddley, funnel, or machinery space ventilators in an exposed position on the freeboard or superstructure deck shall be as high above the deck as is reasonable and practicable. Fiddley openings shall be fitted with strong covers of steel or other equivalent material permanently attached in their proper positions and capable of being secured weathertight.

[CGFR 68–60, 33 FR 10061, July 12, 1968]

§ 42.15-40 Miscellaneous openings in freeboard and superstructure decks.
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(a) Manholes and flush scuttles in position 1 or 2 or within superstructures other than enclosed superstructures shall be closed by substantial covers capable of being made watertight. Unless secured by closely spaced bolts, the covers shall be permanently attached.

(b) Openings in freeboard decks other than hatchways, machinery space openings, manholes, and flush scuttles shall be protected by an enclosed superstructure, or by a deckhouse or companionway of equivalent strength and weathertightness. Any such opening in an exposed superstructure deck or in the top of a deckhouse on the freeboard deck which gives access to a space below the freeboard deck or a space within an enclosed superstructure shall be protected by an efficient deckhouse or companionway. Doorways in such deckhouses or companionways shall be fitted with doors complying with the requirements of §42.15–10(a).

(c) In position 1 the height above the deck of sills to the doorways in companionways shall be at least 23 1/2 inches. In position 2 they shall be at least 15 inches.

[CGFR 68–60, 33 FR 10061, July 12, 1968, as amended by CGFR 68–126, 34 FR 9014, June 5, 1969]

§ 42.15-45 Ventilators.
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(a) Ventilators in position 1 or 2 to spaces below the freeboard decks or decks of enclosed superstructures shall have coamings of steel or other equivalent material, substantially constructed and efficiently connected to the deck. Where the coaming of any ventilator exceeds 35 1/2 inches in height it shall be specially supported.

(b) Ventilators passing through superstructures other than enclosed superstructures shall have substantially constructed coamings of steel or other equivalent material at the freeboard deck.

(c) Ventilators in position 1 the coamings of which extend to more than 14.8 feet above the deck, and in position 2 the coamings of which extend to more than 7.5 feet above the deck, need not be fitted with closing arrangements unless specifically required by the assigning authority.

(d) Except as provided in paragraph (c) of this section ventilator openings shall be provided with efficient weathertight closing appliances. In vessels of not more than 328 feet in length the closing appliances shall be permanently attached; where not so provided in other vessels, they shall be conveniently stowed near the ventilators to which they are to be fitted. Ventilators in position 1 shall have coamings of a height of at least 35 1/2 inches above the deck; in position 2 the coamings shall be of a height at least 30 inches above the deck.

(e) In exposed positions, the height of coamings may be required to be increased to the satisfaction of the assigning authority.

[CGFR 68–60, 33 FR 10061, July 12, 1968, as amended by CGFR 68–126, 34 FR 9014, June 5, 1969]

§ 42.15-50 Air pipes.
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(a) Where air pipes to ballast and other tanks extend above the freeboard or superstructure decks, the exposed parts of the pipes shall be of substantial construction; the height from the deck to the point where water may have access below shall be at least 30 inches on the freeboard deck and 17 1/2 inches on the superstructure deck. Where these heights may interfere with the working of the vessel, a lower height may be approved, provided the assigning authority is satisfied that the closing arrangements and other circumstances justify a lower height. Satisfactory means permanently attached, shall be provided for closing the openings of the air pipes.

[CGFR 68–60, 33 FR 10062, July 12, 1968, as amended by CGFR 68–126, 34 FR 9014, June 5, 1969]

§ 42.15-55 Cargo ports and other similar openings.
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(a) Cargo ports and other similar openings in the sides of vessels below the freeboard deck shall be fitted with doors so designed as to ensure watertightness and structural integrity commensurate with the surrounding shell plating, to the satisfaction of the assigning authority. The arrangements shall be subject to tightness tests at the initial survey and at such subsequent surveys or more frequent intervals as deemed necessary. The number of such openings shall be the minimum compatible with the design and proper working of the vessel.

(b) Unless permitted by the Commandant the lower edge of such openings shall not be below a line drawn parallel to the freeboard deck at side, which has at its lowest point the upper edge of the uppermost load line.

[CGFR 68–60, 33 FR 10062, July 12, 1968, as amended by CGFR 68–126, 34 FR 9014, June 5, 1969]

§ 42.15-60 Scuppers, inlets, and discharges.
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(a) Discharges led through the shell either from spaces below the freeboard deck or from within superstructures and deckhouses on the freeboard deck fitted with doors complying with the requirements of §42.15–10 shall be fitted with efficient and accessible means for preventing water from passing inboard. Normally, each separate discharge shall have one automatic nonreturn valve with a positive means of closing it from a position above the freeboard deck. Where, however, the vertical distance from the summer load waterline to the inboard end of the discharge pipe exceeds 0.01L, the discharge may have two automatic nonreturn valves without positive means of closing: Provided, That the inboard valve is always accessible for examination under service conditions; where that vertical distance exceeds 0.02L a single automatic nonreturn valve without positive means of closing may be accepted subject to the approval of the assigning authority. The means for operating the positive action valve shall be readily accessible and provided with an indicator showing whether the valve is open or closed.

(b) In manned machinery spaces main and auxiliary sea inlets and discharges in connection with the operation of machinery may be controlled locally. The controls shall be readily accessible and shall be provided with indicators showing whether the valves are open or closed.

(c) Scuppers and discharge pipes originating at any level and penetrating the shell either more than 17 1/2 inches below the freeboard deck or less than 23 1/2 inches above the summer load waterline shall be provided with a nonreturn valve at the shell. This valve, unless required by paragraph (a) of this section, may be omitted if the piping is of thickness as specified in Part 56 in Subchapter F (Marine Engineering) of this chapter.

(d) Scuppers leading from superstructures or deckhouses not fitted with doors complying with the requirements of §42.15–10 shall be led overboard.

(e) All valves and shell fittings required by this section shall be of steel, bronze, or other approved ductile material. Valves of ordinary cast iron or similar material are not acceptable. All pipes to which this section refers shall be of steel or other equivalent material to the satisfaction of the assigning authority.

[CGFR 68–60, 33 FR 10062, July 12, 1968, as amended by CGFR 68–126, 34 FR 9014, June 5, 1969]

§ 42.15-65 Side scuttles.
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(a) Side scuttles to spaces below the freeboard deck or to spaces within enclosed superstructures shall be fitted with efficient hinged inside deadlights arranged so that they can be effectively closed and secured watertight.

(b) No side scuttle shall be fitted in a position so that its sill is below a line drawn parallel to the freeboard deck at side and having its lowest point 2.5 percent of the breadth (B) above the load waterline, or 19 1/2 inches, which ever is the greater distance.

(c) The side scuttles, together with their glasses, if fitted, and deadlights, shall be of substantial and approved construction.

[CGFR 68–60, 33 FR 10062, July 12, 1968]

§ 42.15-70 Freeing ports.
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(a) Where bulwarks on the weather portions of freeboard or superstructure decks form wells, ample provision shall be made for rapidly freeing the deck of water and for draining them. Except as provided in paragraphs (b) and (c) of this section, the minimum freeing port area (A) on each side of the vessel for each well on the freeboard deck shall be that given by the following formulae in cases where the sheer in way of the well is standard or greater than standard. The minimum area for each well on superstructure decks shall be one-half of the area given by the formulae.

(1) Where the length of bulwark (l) in the well is 66 feet or less A=7.6+0.115l (square feet)

(2) Where l exceeds 66 feet A=0.23l (square feet)

(3) l need in no case be taken as greater than 0.7L.

(4) If the bulwark is more than 3.9 feet in average height the required area shall be increased by 0.04 square feet per foot of length of well for each foot difference in height. If the bulwark is less than 3 feet in average height, the required area may be decreased by 0.04 square feet per foot of length for each foot difference in height.

(b) In vessels with no sheer the area calculated according to paragraph (a) of this section shall be increased by 50 percent. Where the sheer is less than the standard the percentage shall be obtained by linear interpolation.

(c) Where a vessel is fitted with a trunk which does not comply with the requirements of §42.20–55(a)(5) or where continuous or substantially continuous hatchway side coamings are fitted between detached superstructures the minimum area of the freeing port openings shall be calculated from Table 42.15–70(c):


Table 42.15-70(c)
------------------------------------------------------------------------
Area of freeing ports in
Breadth of hatchway or trunk in relation relation to the total area
to the breadth of vessel of the bulwarks
------------------------------------------------------------------------
40 percent or less........................ 20 percent.
75 percent or more........................ 10 percent.
------------------------------------------------------------------------


Note: The area of freeing ports at intermediate breadths shall be obtained by linear interpolation.

(d) In vessels having superstructures which are open at either or both ends, adequate provision for freeing the space within such superstructures shall be provided to the satisfaction of the assigning authority.

(e) The lower edges of the freeing ports shall be as near the deck as practicable. Two-thirds of the freeing port area required shall be provided in the half of the well nearest the lowest point of the sheer curve.

(f) All such openings in the bulwarks shall be protected by rails or bars spaced approximately 9 inches apart. If shutters are fitted to freeing ports, ample clearance shall be provided to prevent jamming. Hinges shall have pins or bearings of noncorrodible material. If shutters are fitted with securing appliances, these appliances shall be of approved construction.

[CGFR 68–60, 33 FR 10062, July 12, 1968, as amended by CGFR 68–126, 34 FR 9014, June 5, 1969]

§ 42.15-75 Protection of the crew.
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(a) The strength of the deckhouses used for the accommodation of the crew shall be to the satisfaction of the assigning authority.

(b) Efficient guard rails or bulwarks must be fitted on all exposed parts of the freeboard and superstructure decks as follows:

(1) The height of the bulwarks or guard rails must be at least 39 1/2 inches from the deck, provided that where this height would interfere with the normal operation of the vessel, a lesser height may be approved if the Commandant and the assigning authority are satisfied that adequate protection is provided.

(2) On each vessel that is initially surveyed for load line assignment after January 1, 1976, and that is exclusively engaged in towing operations, the minimum bulwark or rail height on the freeboard deck may be reduced to 30 inches provided the assigning authority is satisfied that adequate grabrails are provided around the periphery of the deckhouse.

(3) Portable rails may be used when operating conditions warrant their use.

(c) The opening below the lowest course of the guard rails shall not exceed 9 inches. The other courses shall be not more than 15 inches apart. In the case of vessels with rounded gunwales the guard rail supports shall be placed on the flat of the deck.

(d) Satisfactory means (in the form of guard rails, life lines, gangways or underdeck passages, etc.) shall be provided for the protection of the crew in getting to and from their quarters, the machinery space and all other parts used in the necessary work of the vessel.

(e) Deck cargo carried on any vessel shall be so stowed that any opening which is in way of the cargo and which gives access to and from the crew's quarters, the machinery space and all other parts used in the necessary work of the vessel, can be properly closed and secured against the admission of water. Effective protection for the crew in the form of guard rails or life lines shall be provided above the deck cargo if there is no convenient passage on or below the deck of the vessel.

[CGFR 68–60, 33 FR 10062, July 12, 1968, as amended by CGFR 68–126, 34 FR 9014, June 5, 1969; CGD 74–164, 41 FR 1470, Jan. 8, 1976]

§ 42.15-80 Special conditions of assignment for Type “A” vessels.
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(a) Machinery casings. Machinery casings on Type “A” vessels as defined in §42.09–5(b) must be protected by an enclosed poop or bridge of at least standard height, or by a deckhouse of equal height and equivalent strength, except that machinery casings may be exposed if there are no openings giving direct access from the freeboard deck to the machinery space. A door complying with the requirements of §42.15–10 is permitted in the machinery casing if it leads to a space or passageway which is as strongly constructed as the casing and is separated from the stairway to the engine room by a second weathertight door of steel or equivalent material.

(b) Gangway and access. (1) An efficiently constructed fore and aft permanent gangway of sufficient strength shall be fitted on Type “A” vessels at the level of the superstructure deck between the poop and the midship bridge or deckhouse where fitted, or equivalent means of access shall be provided to carry out the purpose of the gangway, such as passages below deck. Elsewhere, and on Type “A” vessels without a midship bridge, arrangements to the satisfaction of the assigning authority shall be provided to safeguard the crew in reaching all parts used in the necessary work of the ship.

(2) Safe and satisfactory access from the gangway level shall be available between separates crew accommodations and also between crew accommodations and the machinery space.

(c) Hatchways. Exposed hatchways on the freeboard and forecastle decks or on the tops of expansion trunks on Type “A” vessels shall be provided with efficient watertight covers of steel or other equivalent material.

(d) Freeing arrangements. (1) Type “A” vessels with bulwarks shall have open rails fitted for at least half the length of the exposed parts of the weather deck or other effective freeing arrangements. The upper edge of the sheer strake shall be kept as low as practicable.

(2) Where superstructures are connected by trunks, open rails shall be fitted for the whole length of the exposed parts of the freeboard deck.

[CGFR 68–60, 33 FR 10063, July 12, 1968, as amended by CGFR 68–126, 34 FR 9014, June 5, 1969; CGD 79–153, 48 FR 38647, Aug. 25, 1983]

Subpart 42.20—Freeboards
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§ 42.20-3 Freeboard assignment: Type “A” vessels.
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(a) A Type “A” vessel is assigned a freeboard not less than that based on Table 42.20–15(a)(1) provided that the vessel meets the flooding standard in §42.20–6.

(b) A vessel that meets the requirements of Subpart D, F, or G of Part 172 of this chapter is considered by the Coast Guard as meeting the flooding standard referenced in paragraph (a) of this section.

[CGD 79–153, 48 FR 38647, Aug. 25, 1983 as amended by CGD 79–023, 49 FR 26593, June 28, 1984]

§ 42.20-5 Freeboard assignment: Type “B” vessels.
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(a) Each Type “B” vessel is assigned a freeboard from Table 42.20–15(b)(1) that is increased or decreased by the provisions of this section.

(b) Each Type “B” vessel that has a hatchway in position 1, must have the freeboard assigned in accordance with paragraph (a) of this section increased by the amount given in Table 42.20–5(b) unless the hatch cover complies with:

(1) Section 42.15–25(d); or

(2) Section 42.15–30.


Table 42.20-5(b)_Freeboard Increase Over Tabular Freeboard for Type
``B'' Vessels With Hatch Covers Not Complying With § 42.15-25(d) or
§ 42.15-30.
[Metric]
------------------------------------------------------------------------
Length of ship (meters) Freeboard increase 1 (millimeters)
------------------------------------------------------------------------
\2\108 50
109 52
110 55
111 57
112 59
113 62
114 64
115 68
116 70
117 73
118 76
119 80
120 84
121 87
122 91
123 95
124 99
125 103
126 108
127 112
128 116
129 121
130 126
131 131
132 136
133 142
134 147
135 153
136 159
137 164
138 170
139 175
140 181
141 186
142 191
143 196
144 201
145 206
146 210
147 215
148 219
149 224
150 228
151 232
152 236
153 240
154 244
155 247
156 251
157 254
158 258
159 261
160 264
161 267
162 270
163 273
164 275
165 278
166 280
167 283
168 285
169 287
170 290
171 292
172 294
173 297
174 299
175 301
176 304
177 306
178 308
179 311
180 313
181 315
182 318
183 320
184 322
185 325
186 327
187 329
188 332
189 334
190 336
191 339
192 341
193 343
194 346
195 348
196 350
197 353
198 355
199 357
\3\200 358
------------------------------------------------------------------------
\1\ Freeboards at intermediate lengths of ship shall be obtained by
linear interpolation.
\2\ 108 and below.
\3\ Ships above 200 meters in length are subject to individual
determination by the Commandant.




[English]
------------------------------------------------------------------------
Length of ship (feet) Freeboard increase \1\ (inches)
------------------------------------------------------------------------
\2\350 2.0
360 2.3
370 2.6
380 2.9
390 3.3
400 3.7
410 4.2
420 4.7
430 5.2
440 5.8
450 6.4
460 7.0
470 7.6
480 8.2
490 8.7
500 9.2
510 9.6
520 10.0
530 10.4
540 10.7
550 11.0
560 11.4
570 11.8
580 12.1
590 12.5
600 12.8
610 13.1
620 13.4
630 13.6
640 13.9
650 14.1
\3\660 14.3
------------------------------------------------------------------------
\1\ Freeboards at intermediate lengths of ship be obtained by linear
interpolation.
\2\ 350 and below.
\3\ Ships above 660 feet in length are subject to individual
determination by the Commandant.


(c) Any Type “B” vessel that is greater than 100 meters (328 feet) in length and any hopper dredge meeting the requirements in Subpart C of Part 44 of this chapter may have a reduced freeboard from that assigned under Table 42.20–15(b)(1) in accordance with paragraph (d) or paragraph (e) of this section if—

(1) The measures provided for the protection of the crew are adequate;

(2) The freeing arrangements are adequate; and

(3) The hatchway covers in positions 1 and 2 comply with the provisions of §42.15–30 and have adequate strength, special care being given to their sealing and securing arrangements.

(d) The freeboards for a Type “B” vessel which comply with paragraph (c) of this section may be reduced up to 60 percent of the total difference between the freeboards in Table 42.20–15(b)(1) and Table 42.20–15(a)(1) provided that the vessel meets the flooding standard in §42.20–7.

(e) The freeboards for a Type “B” vessel which complies with paragraph (c) of this section may be reduced up to the total difference between the freeboard tables referenced in paragraph (d) of this section provided that the vessel meets the flooding standard in §42.20–8 and the provisions of §42.15–80 (a), (b) and (d) as if it were a Type “A” vessel.

[CGD 79–153, 48 FR 38647, Aug. 25, 1983, as amended by CGD 76–080, 54 FR 36976, Sept. 6, 1989]

§ 42.20-6 Flooding standard: Type “A” vessels.
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(a) Design calculations must be submitted that demonstrate that the vessel will remain afloat in the conditions of equilibrium specified in §42.20–12 assuming the damage specified in §42.20–11 as applied to the following flooding standards:

(1) If the vessel is over 150 meters (492 feet) in length it must be able to withstand the flooding of any one compartment, except the machinery space.

(2) If the vessel is over 225 meters (738 feet) in length, it must be able to withstand the flooding of any one compartment, treating the machinery space as a floodable compartment.

(b) When doing the calculations required in paragraph (a) of this section, the following permeabilities must be assumed:

(1) 0.95 in all locations except the machinery space.

(2) 0.85 in the machinery space.

[CGD 79–153, 48 FR 38648, Aug. 25, 1983]

§ 42.20-7 Flooding standard: Type “B” vessel, 60 percent reduction.
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(a) Design calculations must be submitted that demonstrate that the vessel will remain afloat in the conditions of equilibrium specified in §42.20–12 assuming the damage specified in §42.20–11 as applied to the following flooding standards:

(1) If the vessel is 225 meters (738 feet) or less in length, it must be able to withstand the flooding of any one compartment, except the machinery space.

(2) If the vessel is over 225 meters (738 feet) in length, it must be able to withstand the flooding of any one compartment, treating the machinery space as a floodable compartment.

(b) When doing the calculations required in paragraph (a) of this section, the following permeabilities must be assumed:

(1) 0.95 in all locations except the machinery space.

(2) 0.85 in the machinery space.

[CGD 79–153, 48 FR 38648, Aug. 25, 1983]

§ 42.20-8 Flooding standard: Type “B” vessel, 100 percent reduction.
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(a) Design calculations must be submitted that demonstrate that the vessel will remain afloat in the conditions of equilibrium specified in §42.20–12 assuming the damage specified in §42.20–11 as applied to the following flooding standards:

(1) If the vessel is 225 meters (738 feet) or less in length, it must be able to withstand the flooding of any two adjacent fore and after compartments excluding the machinery space;

(2) If the vessel is over 225 meters (738 feet) in length, the flooding standard of paragraph (a)(1) of this section must be applied, treating the machinery space, taken alone, as a floodable compartment.

(b) When doing the calculations required in paragraph (a) of this section, the following permeabilities must be assumed:

(1) 0.95 in all locations except the machinery space.

(2) 0.85 in the machinery space.

[CGD 79–153, 48 FR 38648, Aug. 25, 1983]

§ 42.20-9 Initial conditions of loading.
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When doing the calculations required in §§42.20–6(a), 42.20–7(a) and 42.20–8(a), the initial condition of loading before flooding must be assumed to be as specified in this section:

(a) The vessel is assumed to be loaded to its summer load waterline with no trim.

(b) When calculating the vertical center of gravity, the following assumptions apply:

(1) The cargo is assumed to be homogeneous.

(2) Except as specified in paragraph (b)(3) of this section, all cargo compartments are assumed to be fully loaded. This includes compartments intended to be only partially filled. In the case of liquid cargoes, fully loaded means 98 percent full.

(3) If the vessel is intended to operate at its summer load waterline with empty compartments, these empty compartments are assumed to be empty rather than fully loaded if the resulting height of the vertical center of gravity is not less than the height determined in accordance with paragraph (b)(2) of this section.

(4) Fifty percent of the total capacity of all tanks and spaces fitted to contain consumable liquids or stores must be assumed to be distributed to accomplish the following:

(i) Each tank and space fitted to contain consumable liquids or stores must be assumed either completely empty or completely filled.

(ii) The consumables must be distributed so as to produce the greatest possible height above the keel for the center of gravity.

(5) Weights are calculated using the following values for specific gravities:


Salt water—1.025

Fresh water—1.000

Oil fuel—0.950

Diesel oil—0.900

Lube oil—0.900


[CGD 79–153, 48 FR 38648, Aug. 25, 1983]

§ 42.20-10 Free surface.
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When doing the calculations required in §§42.20–6(a), 42.20–7(a) and 42.20–8(a), the effect of free surface of the following liquids must be included:

(a) For each type of consumable liquid, the maximum free surface of at least one transverse pair of tanks or a single centerline tank must be included. The tank or combination of tanks must be that resulting in the greatest free surface effect.

(b) For cargo liquids, unless the compartment is assumed to be empty as required by §42.20–9(b)(3), the free surface of those compartments containing liquids is calculated at an angle of heel of not more than 5 degrees.

[CGD 79–153, 48 FR 38649, Aug. 25, 1983]

§ 42.20-11 Extent of damage.
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When doing the calculations required by §§42.20–6(a), 42.20–7(a) and 42.20–8(a), the following must be assumed:

(a) The vertical extent of damage in all cases must be assumed to be from the baseline upward without limit.

(b) The transverse extent of damage is assumed to be equal to B/5 or 11.5 meters (37.7 feet), whichever is less. The transverse extent is measured inboard from the side of the ship perpendicularly to the center line at the level of the summer load waterline.

(c) If damage of a lesser extent than that specified in paragraph (a) or (b) of this section results in a more severe condition, the lesser extent must be assumed.

(d) The following assumptions apply to the transverse damage specified in paragraph (b) of this section for a stepped or recessed bulkhead:

(1) A transverse watertight bulkhead that has a step or recess located within the transverse extent of assumed damage may be considered intact if the step or recess is not more than 3.05 meters (10 feet) in length.

(2) If a transverse watertight bulkhead has a step or recess of more than 3.05 meters (10 feet) in length, within the transverse extent of assumed damage, the two compartments adjacent to this bulkhead must be considered as flooded.

(3) If within the transverse extent of damage, a transverse bulkhead has a step or recess more than 3.05 meters (10 feet) in length that coincides with the double bottom tank top or the inner boundary of a wing tank, respectively, all adjacent compartments within the transverse extent of assumed damage must be considered to be flooded simultaneously.

(e) If a wing tank has openings into adjacent compartments, the wing tank and adjacent compartments must be considered as one compartment. This provision applies even where these openings are fitted with closing appliances except:

(1) Valves fitted in bulkheads between tanks which are controlled from above the bulkhead deck.

(2) Secured manhole covers fitted with closely spaced bolts.

(f) Only transverse watertight bulkheads that are spaced apart at least 1/3(L) 2/3 or 14.5 meters (0.495(L) 2/3 or 47.6 feet), whichever is less, may be considered effective. If transverse bulkheads are closer together, then one or more of these bulkheads must be assumed to be non-existent in order to achieve the minimum spacing between bulkheads.

[CGD 79–153, 48 FR 38649, Aug. 25, 1983]

§ 42.20-12 Conditions of equilibrium.
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The following conditions of equilibrium are regarded as satisfactory:

(a) Downflooding. The final waterline after flooding, taking into account sinkage, heel, and trim, is below the lower edge of any opening through which progressive flooding can take place. Such openings include air pipes, ventilators, and openings which are closed by means of weathertight doors (even if they comply with §42.15–10) or covers (even if they comply with §42.15–30 or §42.15–45(d)) but may exclude those openings closed by means of:

(1) Manhole covers and flush scuttles which comply with §42.15–40;

(2) Cargo hatch covers which comply with §42.09–5(b);

(3) Hinged watertight doors in an approved position which are secured closed while at sea and so logged; and

(4) Remotely operated sliding watertight doors, and side scuttles of the non-opening type which comply with §42.15–65.

(b) Progressive flooding. If pipes, ducts, or tunnels are situated within the assumed extent of damage penetration as defined in §42.20–11 (a) and (b), progressive flooding cannot extend to compartments other than those assumed to be floodable in the calculation for each case of damage.

(c) Final angle of heel. The angle of heel due to unsymmetrical flooding does not exceed 15 degrees. If no part of the deck is immersed, an angle of heel of up to 17 degrees may be accepted.

(d) Metacentric height. The metacentric height of the damaged vessel, in the upright condition, is positive.

(e) Residual stability. Through an angle of 20 degrees beyond its position of equilibrium, the vessel must meet the following conditions:

(1) The righting arm must be positive.

(2) The maximum righting arm must be at least 0.1 meter (4 inches).

(3) The area under the righting arm curve within the 20 degree range must not be less than 0.0175 meter-radians (0.689 inch-radians).

(4) Each submerged opening must be weathertight (e.g. a vent fitted with a ball check valve).

(f) Intermediate stages of flooding. The Commandant is satisfied that the stability is sufficient during intermediate stages of flooding.

[CGD 79–153, 48 FR 38649, Aug. 25, 1983]

§ 42.20-13 Vessels without means of propulsion.
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(a) A lighter, barge, or other vessel without independent means of propulsion is assigned a freeboard in accordance with the provisions of this subpart as modified by paragraphs (b), (c), and (d) of this section.

(b) A barge that meets the requirements of §42.09–5(b) may be assigned Type “A” freeboard if the barge does not carry deck cargo.

(c) An unmanned barge is not required to comply with §42.15–75, §42.15–80(b), or §42.20–70.

(d) An unmanned barge that has only small access openings closed by watertight gasketed covers of steel or equivalent material on the freeboard deck, may be assigned a freeboard 25 percent less than that calculated in accordance with this subpart.

[CGD 79–153, 48 FR 38649, Aug. 25, 1983]

§ 42.20-15 Freeboard tables.
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(a) Type “A” vessel. (1) The tabular freeboard for Type “A” vessel shall be determined from Table 42.20–15(a)(1):


Table 42.20-15(a)(1)_Freeboard Table for Type ``A'' Vessels
------------------------------------------------------------------------
Freeboard
Length of vessel (feet) \1\
(inches)
------------------------------------------------------------------------
80........................................................... 8.0
90........................................................... 8.9
100.......................................................... 9.8
110.......................................................... 10.8
120.......................................................... 11.9
130.......................................................... 13.0
140.......................................................... 14.2
150.......................................................... 15.5
160.......................................................... 16.9
170.......................................................... 18.3
180.......................................................... 19.8
190.......................................................... 21.3
200.......................................................... 22.9
210.......................................................... 24.5
220.......................................................... 26.2
230.......................................................... 27.8
240.......................................................... 29.5
250.......................................................... 31.1
260.......................................................... 32.8
270.......................................................... 34.6
280.......................................................... 36.3
290.......................................................... 38.0
300.......................................................... 39.7
310.......................................................... 41.4
320.......................................................... 43.2
330.......................................................... 45.0
340.......................................................... 46.9
350.......................................................... 48.8
360.......................................................... 50.7
370.......................................................... 52.7
380.......................................................... 54.7
390.......................................................... 56.8
400.......................................................... 58.8
410.......................................................... 60.9
420.......................................................... 62.9
430.......................................................... 65.0
440.......................................................... 67.0
450.......................................................... 69.1
460.......................................................... 71.1
470.......................................................... 73.1
480.......................................................... 75.1
490.......................................................... 77.1
500..........................................................79.0 (continued)