[Code of Federal Regulations]
[Title 46, Volume 7]
[Revised as of October 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR174.185]

[Page 175-176]
 
                           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. 174.185  Intact stability.

    (a) Each OSV must be shown by design calculations to meet, under 
each condition of loading and operation, the minimal requirements for 
metacentric height (GM) in Sec. 170.170 of this chapter, and in either 
Sec. 170.173 of this chapter or paragraphs (b) through (e) of this 
section.
    (b) The area under each righting arm curve must be at least 0.08 
meter-radians (15 foot-degrees) up to the smallest of the following 
angles:
    (1) The angle of maximum righting arm;
    (2) The downflooding angle; or
    (3) 40 degrees.
    (c) The downflooding angle must not be less than 20 degrees.
    (d) The righting arm curve must be positive to at least 40 degrees.
    (e) The freeboard at the stern must be equal to the freeboard 
calculated to comply with subchapter E of this chapter or to the value 
taken from Table 174.185, whichever is less.
    (f) For paragraphs (b) and (d) of this section, at each angle of 
heel an OSV's righting arm may be calculated considering either--
    (1) The vessel is permitted to trim free until the trimming moment 
is zero; or
    (2) The vessel does not trim as it heels.
    (g) For the purpose of paragraphs (b) and (d) of this section, the 
method of calculating righting arms chosen must be the same for all 
calculations.

[[Page 176]]



              Table 174.185--Minimal Freeboard at the Stern
------------------------------------------------------------------------
                                                              Freeboard
                                                             at stern in
                    LBP in meters (feet)                     millimeters
                                                               (inches)
------------------------------------------------------------------------
Less than 20 (65)..........................................     300 (12)
20 (65) but less than 30 (100).............................     380 (15)
30 (100) but less than 40 (130)............................     400 (18)
40 (130) but less than 50 (155)............................     500 (20)
50 (155) but less than 60 (190)............................     560 (22)
60 (190) but less than 70 (230)............................     610 (24)
70 (230) and greater.......................................     660 (26)
------------------------------------------------------------------------