Internal structural examination
Internal structural examination means an examination of the vessel while afloat or in drydock and consists of a complete examination of the vessel's main strength members, including the major internal framing, the hull plating, voids, and ballast tanks, but not including cargo, sewage, or fuel oil tanks.
46 CFR § 114.400
Terms used in this subchapter are defined in paragraph (b) of this section. The number in parenthesis after certain terms describing areas on a vessel refers to the applicable column and row number where that area is listed in Tables 116.415 (b) and (c) of part 116 of this subchapter.