[Code of Federal Regulations]
[Title 46, Volume 2]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR69.113]

[Page 402]
 
                           TITLE 46--SHIPPING
 
   CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
 
PART 69_MEASUREMENT OF VESSELS--Table of Contents
 
                  Subpart C_Standard Measurement System
 
Sec. 69.113  Superstructure tonnage.

    (a) Defined. ``Superstructure tonnage'' means the tonnage of all 
permanent structures, such as forecastle, bridge, poop, deckhouse, and 
break, on or above the line of the uppermost complete deck (or line of 
shelter deck, if applicable).
    (b) Method of calculating tonnage. The tonnage of all structures on 
each level on or above the uppermost complete deck (or shelter deck, if 
applicable) is calculated separately as follows:
    (1) The length of each structure is measured along its centerline at 
mid-height between the line of the inboard face of the framing on one 
end to the line of the inboard face of the framing on the other end. 
(See Sec. 69.123, figure 11.)
    (2) Divide the length under paragaph (b)(1) of this section into an 
even number of equal parts most nearly equal to those into which the 
tonnage length is divided under Sec. 69.109.
    (3) Measure at mid-height the inside breadth at each end and at each 
point of division of the length. Number the breadths successively ``1'', 
``2'', and so forth, beginning at the extreme forward end of the 
structure. If an end of the structure is in the form of a continuous arc 
or curve, the breadth at that end is one-half the nearest breadth. If an 
end is in the form of an arc or curve having a decided flat, the breadth 
at the end is two-thirds of the nearest breadth.
    (4) Multiply the even numbered breadths by four and the odd numbered 
by two, except the first and last breadth, which are multiplied by one.
    (5) Add together the products under paragraph (b)(4) of this section 
and multiply the sum by one-third of the interval between the points at 
which the breadths are taken. The product is the square foot area of the 
structure at mid-height.
    (6) Multiply this area by the average of the heights taken at each 
point of division of the structure between its decks or the line of its 
decks. The product divided by 100 is the tonnage of that structure.
    (c) A structure having steps in its deck or side must be measured in 
parts.
    (d) The superstructure tonnage is the sum of tonnages of each level 
above the line of the uppermost complete deck (or shelter deck, if 
applicable).
    (e) When a structure is located over a cut-away portion of the 
tonnage deck, the structure's height is measured from the under side of 
its overhead deck to the line of the tonnage deck. If the tonnage deck 
has no camber, allow for camber in the overhead deck.
    (f) For structures of a standard geometric shape, a simple geometric 
formula that yields an accurate volume may be used.