69.65—Calculation of volumes.
(a)
Volumes V and Vc used in calculating gross and net tonnages, respectively, must be measured and calculated according to accepted naval architectural practices for the spaces concerned.
(1)
If the number and location of sections originally used in making other calculations which relate to the form of the vessel (such as displacement volumes and center of buoyancy) are reasonably available, Simpson's first rule may be applied using those sections.
(2)
If the number and location of stations originally used are not reasonably available or do not exist and the hull is of conventional design with faired lines, Simpson's first rule may be applied using a number and location of stations not less than those indicated in § 69.109(g)(1).
(3)
If the hull is of standard geometric shape, a simple geometric formula that yields a more accurate volume may be used.
(4)
If the lines of the hull are not fair, the volume may be measured by using a combination of methods under this section.
(c)
The volume of structures above the upper deck may be measured by applying the superstructure provisions in § 69.113 or by any accepted method or combinations of methods.
(1)
To the inner side of the shell or structural boundary plating, in vessels constructed of metal; and
(2)
To the outer surface of the shell or to the inner side of structural boundary surfaces, in all other vessels.
(e)
When determining the volume of a cargo space, measurements must be taken without consideration for insulation, sparring, or ceiling fitted within the space.
(g)
Calculations must be made on a worksheet and must be sufficiently detailed to permit easy review. The measurement procedures used must be identified on the worksheet.