[Code of Federal Regulations]
[Title 46, Volume 7]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR174.207]

[Page 176-177]
 
                           TITLE 46--SHIPPING
 
   CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
 
PART 174_SPECIAL RULES PERTAINING TO SPECIFIC VESSEL TYPES--Table of 
Contents
 
      Subpart G_Special Rules Pertaining to Offshore Supply Vessels
 
Sec. 174.207  Damaged stability criteria.

    (a) Extent of damage. Damage must consist of penetrations having the 
dimensions specified by table 174.207(a) of this section, except that, 
if the most disabling penetrations are smaller than the penetrations 
specified by the table, damage must consist of the smaller penetrations.
    (b) Permeability of spaces. The permeability of a floodable space 
must be as specified by Table 174.207(b) of this section.
    (c) Survival conditions. An OSV is presumed to survive assumed 
damage if it meets the following conditions in the final stage of 
flooding:
    (1) Final waterline. The final waterline, in the final stage of 
sinkage, heel, and trim, must be below the lower edge of an opening 
through which progressive flooding may take place, such as an air pipe, 
a tonnage opening, an

[[Page 177]]

opening closed by a weathertight door or hatch-cover, or a tank vent 
fitted with a ball check-valve. This opening does not include an opening 
closed by a--
    (i) Watertight manhole-cover;
    (ii) Flush scuttle;
    (iii) Small hatch-cover for a watertight cargo-tank that maintains 
the high integrity of the deck;
    (iv) Watertight door in compliance with Sec. 174.210 of this 
subpart; or
    (v) Side scuttle of the non-opening type.
    (2) Angle of heel. The angle of heel must not exceed 15 degrees.
    (3) Range of stability. Through an angle of 20 degrees beyond its 
position of equilibrium after flooding, an OSV must meet the following 
conditions:
    (i) The righting arm curve must be positive.
    (ii) The righting arm must be at least 100 millimeters (4 inches).
    (iii) Each submerged opening must be weathertight. (A tank vent 
fitted with a ball check-valve is weathertight.)
    (4) Progressive flooding. Piping, ducts, or tunnels within the 
assumed extent of damage must be either--
    (i) Equipped with arrangements, such as stop check-valves, to 
prevent progressive flooding of the spaces with which they connect; or
    (ii) Assumed in the calculations required by paragraph (a) of this 
section to permit progressive flooding of the spaces with which they 
connect.
    (d) Buoyancy of superstructure. For paragraph (a) of this section, 
the buoyancy of any superstructure directly above the side damage must 
be considered in the most unfavorable condition.

                   Table 174.207(a)--Extent of Damage
------------------------------------------------------------------------

------------------------------------------------------------------------
                          Collision Penetration
Longitudinal extent (vessels with LBP not   .1L or 1.8 meters (6 feet):,
 greater than 45 meters [143 feet]).         whichever is greater in
                                             length.
Longitudinal extent (vessels with LBP       3 meters (10 feet) + .03L.
 greater than 45 meters [143 feet]).
Transverse extent*........................  760 millimeters (30 inches).
Vertical extent...........................  From baseline upward without
                                             limit.
------------------------------------------------------------------------
*The transverse penetration applies inboard from the side of the vessel,
  at right angles to the centerline, at the level of the deepest load
  waterline.


                Table 174.207(b)--Permeability of Spaces
------------------------------------------------------------------------
             Spaces and tanks                       Permeability
------------------------------------------------------------------------
Storerooms................................  60 percent.
Accommodations............................  95 percent.
Machinery.................................  85 percent.
Voids and passageways.....................  95 percent.
Dry-bulk tanks............................  0 (*) or 95 percent.
Consumable-liquid tanks...................  0 (*) or 95 percent.
Other liquid tanks........................  0 (*) 0 (**) or 95 percent.
------------------------------------------------------------------------
*Whichever results in the more disabling condition.
**If tanks are partly filled, the permeability must be determined from
  the actual density and amount of liquid carried.