[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: 46CFR174.045]

[Page 170-171]
 
                           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 C_Special Rules Pertaining to Mobile Offshore Drilling Units
 
Sec. 174.045  Intact stability requirements.

    (a) Each unit must be designed so that the wind heeling moments (Hm) 
and righting moments calculated for each of its normal operating 
conditions and severe storm conditions, when plotted on GRAPH 174.045, 
define areas that satisfy the equation:

Area(A)=(K)x(Area (B))

where--

(1) K=1.4 except that if the unit is a column stabilized unit K=1.3;
(2) Area (A) is the area on GRAPH 174.045 under the righting moment 
curve between 0 and the second intercept angle or the angle of heel at 
which downflooding would occur, whichever angle is less; and
(3) Area (B) is the area on GRAPH 174.045 under the wind heeling moment 
curve between 0 and the second intercept angle or the angle of heel at 
which downflooding of the unit would occur whichever angle is less.

    (b) Each righting moment on graph Sec. 174.045 must be positive for 
all angles

[[Page 171]]

greater than 0 and less than the second intercept angle.
    (c) For the purposes of this section, openings fitted with the 
weathertight closing appliances specified in Sec. 174.100(b) are not 
considered as openings through which downflooding could occur if they 
can be rapidly closed and would not be submerged below the units' 
waterline prior to the first intercept angle, except that ventilation 
intakes and outlets for machinery spaces, crew spaces, and other spaces 
where ventilation is normally required are considered as openings 
through which downflooding could occur regardless of location.
    (d) Each unit must be designed so that it can be changed from each 
of its normal operating conditions to a severe storm condition within a 
minimum period of time consistent with the operating manual required in 
Sec. 109.121 of this chapter.
[GRAPHIC] [TIFF OMITTED] TC01MR91.034


[CGD 79-023, 48 FR 51048, Nov. 4, 1983, as amended by CGD 83-071, 52 FR 
6979, Mar. 6, 1987]