[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: 46CFR170.170]

[Page 102-103]
 
                           TITLE 46--SHIPPING
 
   CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
 
PART 170--STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS--Table of Contents
 
                       Subpart E--Weather Criteria
 
Sec. 170.170  Calculations required.

    (a) Each vessel must be shown by design calculations to have a 
metacentric height (GM) that is equal to or greater than the following 
in each condition of loading and operation:
[GRAPHIC] [TIFF OMITTED] TC13NO91.043

Where--

P=.005+(L/14,200)\2\ tons/ft\2\ . . . for ocean service, Great Lakes 
winter service, or service on exposed waters.
P=.055+(L/1309)\2\ metric tons/m\2\ . . . for ocean service, Great Lakes 
winter service, or service on exposed waters.
P=.0033+(L/14,200)\2\ tons/ft\2\ . . . for Great Lakes summer service or 
service on partially protected waters.
P=.036+(L/1309)\2\ metric tons/m\2\ . . . for Great lakes summer service 
or service on partially protected waters.
P=.0025+(L/14,200)\2\ tons/ft\2\ . . . for service on protected waters.
P=.028+(L/1309)\2\ metric tons/m\2\ . . . for service on protected 
waters.
L=LBP in feet (meters).
A=projected lateral area in square feet (square meters) of the portion 
of the vessel and deck cargo above the waterline.
H=the vertical distance in feet (meters) from the center of A to the 
center of the underwater lateral area or approximately to the one-half 
draft point.
W=displacement in long (metric) tons.
T=either:
    (1) the lesser of either 14 degrees heel or the angle of heel in 
degrees at which one-half the freeboard to the deck edge is immersed; or
    (2) for a sailing vessel, T = the lesser of either 14 degrees or the 
angle of heel in degrees to the deck edge.
    The deck edge is to be taken as the intersection of the sideshell 
and the uppermost continuous deck below which the sideshell is 
weathertight.

    (b) If approved by the Coast Guard Marine Safety Center or the ABS, 
a

[[Page 103]]

larger value of T may be used for a vessel with a discontinuous weather 
deck or abnormal sheer.
    (c) When doing the calculations required by paragraph (a) of this 
section for a sailing vessel or auxiliary sailing vessel, the vessel 
must be assumed--
    (1) To be under bare poles; or
    (2) If the vessel has no auxiliary propulsion, to have storm sails 
set and trimmed flat.
    (d) The criterion specified in this section is generally limited in 
application to flush deck, mechanically powered vessels of ordinary 
proportions and form that carry cargo below the main deck. On other 
types of vessels, the Coast Guard Marine Safety Center or the ABS 
requires calculations in addition to those in paragraph (a) of this 
section. On a mechanically powered vessel under 328 feet (100 meters) in 
length, other than a tugboat or a towboat, the requirements in 
Sec. 170.173 are applied.

[CGD 79-023, 48 FR 51010, Nov. 4, 1983; 49 FR 37384, Sept. 24, 1984, as 
amended by CGD 88-070, 53 FR 34537, Sept. 7, 1988; CGD 85-080, 61 FR 
944, Jan. 10, 1996; 61 FR 20556, May 7, 1996; CGD 95-028, 62 FR 51217, 
Sept. 30, 1997]