[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: 46CFR174.045]

[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)[ge](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 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

[[Page 171]]

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]