🔍 Key Concepts

• Difference between ullage, innage, outage, and thievage in cargo tank measurements • How tank depth can be measured: from bottom up versus top down • Standard petroleum cargo measurement terms used in tanker operations

💭 Think About

• For each term, ask yourself: does this describe the amount of liquid, the empty space above the liquid, or the method of taking a measurement? • Think about which term would be used when you want to know how full the tank is from the bottom rather than how much space is left at the top. • Recall which word is linked to taking a sample or sounding versus the actual quantity or level in the tank.

✅ Before You Answer

• Identify which term means the empty space from liquid surface to the top of the tank and rule that one out if the question asks for depth of product. • Identify which term is associated with taking a thief sample or measurement method, not the level itself. • Focus on the term that directly refers to the height (depth) of liquid from the bottom reference point inside the tank.