🔍 Key Concepts

• Ullage and how it relates to liquid depth in the tank • How to find the vertical center of gravity (VCG) of the liquid in the tank from the tank plan or hydrostatic tables • How to compute a vertical moment once you know weight and its vertical lever arm

💭 Think About

• From the given ullage of 3.0 feet, what is the actual liquid depth in P-Tank #1 based on the tank’s reference dimensions? • Once you know the liquid depth, where is the vertical center of that liquid above the tank baseline or reference point? • How do you use the tank’s weight of liquid at that filling and the VCG to calculate a vertical moment?

✅ Before You Answer

• Verify the correct liquid depth = tank reference height − ullage (check the tank calibration or capacity plan). • Confirm you are using the correct weight of liquid in P-Tank #1 at that ullage from the capacity/ULLAGE table. • Make sure the vertical moment = weight × vertical distance (lever arm) and that units are in foot-tons.