Question 1113 Deck General

The correct answer is A) an above-deck datum such as the top of the ullage pipe. Ullage refers to the empty space in a tank, and on tankers, ullages are measured from an above-deck datum, typically the top of the ullage pipe. This is the standard practice specified in regulations and industry standards for taking accurate ullage measurements on tankers. The other options are incorrect because: B) the tank ceiling is not the standard reference point, C) the tank top is too low to serve as the reference, and D) a thievage mark below the deck edge is not the typical measurement point used.