46 C.F.R. § 153.979 Gauging with a sounding tube.
Title 46 - Shipping
(a) No person may remove the cover of a sounding tube unless he has authorization from the person in charge of cargo transfer. (b) The person in charge of cargo transfer may not authorize removal of the cover from a sounding tube gauge unless all tank pressure has been relieved through the tank's venting system.
Title 46: Shipping
PART 153—SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS
Subpart C—Operations
Cargo Transfer Procedures
§ 153.979 Gauging with a sounding tube.

