46 CFR §154.1340

1. (a)Each cargo tank must have devices that measure the temperature:
   1. (1)At the bottom of the tank; and
   2. (2)Near the top of the tank and below the maximum liquid level allowed under § 154.1844.
2. (b)Each device required by paragraph (a) must have a readout at the cargo control station.
3. (c)Except for independent tanks type C, each cargo containment system for a design temperature colder than −55 °C (−67 °F) must have temperature measuring devices that meet the following:
   1. (1)The number and location of the devices must be specially approved by the Commandant (CG-OES).
   2. (2)The devices must be within the cargo tank's insulation or on the adjacent hull structure.
   3. (3)Each device must show the temperature continuously or at regular intervals of one hour or less.
   4. (4)Each device must actuate an audible and visual alarm at the cargo control station and a remote group alarm in the wheelhouse before the temperature of the steel of the adjacent hull structure is cooled below the lowest temperature allowed for the steel under § 154.172.
4. (d)For each cargo tank with a design temperature colder than −55 °C (−67 °F), the number and arrangement of the devices that show the temperature of the tank during cool down procedures must be specially approved by the Commandant (CG-OES).