[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: 46CFR172.195]

[Page 155]
 
                           TITLE 46--SHIPPING
 
   CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
 
PART 172_SPECIAL RULES PERTAINING TO BULK CARGOES--Table of Contents
 
    Subpart G_Special Rules Pertaining to a Ship That Carries a Bulk 
       Liquefied Gas Regulated Under Subchapter O of This Chapter
 
Sec. 172.195  Survival conditions.

    A vessel is presumed to survive assumed damage if it meets the 
following conditions in the final stage of flooding:
    (a) Final waterline. The final waterline, in the final condition 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, 
or an opening that is closed by means of a weathertight door or hatch 
cover. This opening does not include an opening closed by a--
    (1) Watertight manhole cover;
    (2) Flush scuttle;
    (3) Small watertight cargo tank hatch cover that maintains the high 
integrity of the deck;
    (4) A Class 1 door in a watertight bulkhead within the 
superstructure;
    (5) Remotely operated sliding watertight door; or
    (6) A side scuttle of the non-opening type.
    (b) Heel angle. The maximum angle of heel must not exceed 30 
degrees.
    (c) Range of stability. Through an angle of 20 degrees beyond its 
position of equilibrium after flooding, a tankship must meet the 
following conditions:
    (1) The righting arm curve must be positive.
    (2) The maximum righting arm must be at least 3.94 inches (10 cm).
    (3) Each submerged opening must be weathertight.
    (d) Progressive flooding. If pipes, ducts, or tunnels are within the 
assumed extent of damage, arrangements must be made to prevent 
progressive flooding to a space that is not assumed to be flooded in the 
damaged stability calculations.
    (e) Buoyancy of superstructure. The buoyancy of any superstructure 
directly above the side damage is to be disregarded. The unflooded parts 
of superstructures beyond the extent of damage may be taken into 
consideration if they are separated from the damaged space by watertight 
bulkheads and no progressive flooding of these intact spaces takes 
place.
    (f) Metacentric height. After flooding, the tank ship's metacentric 
height must be at least 2 inches (50 mm) when the vessel is in the 
upright position.
    (g) Equalization arrangements. Equalization arrangements requiring 
mechanical aids such as valves or cross-flooding lines may not be 
considered for reducing the angle of heel. Spaces joined by ducts of 
large cross-sectional area are treated as common spaces.
    (h) Intermediate stages of flooding. If an intermediate stage of 
flooding is more critical than the final stage, the tank vessel must be 
shown by design calculations to meet the requirements in this section in 
the intermediate stage.