🔍 Key Concepts

• motions of a floating MODU (heave, roll, and pitch) and how each affects depth readings • how a sounding tape actually gets its reading (what part of the tape or bob shows the level) • the purpose of lowering and recovering the tape quickly when the vessel or unit is moving in a seaway

💭 Think About

• Think about which kind of motion changes the vertical distance between the keel and the sea surface, and how that might affect the apparent liquid level in a tank or space. • Consider whether quickly lowering and raising the tape would change how much the tube is exposed, or whether it is more about getting a reading before a certain type of motion can distort it. • Ask yourself which motion—roll, pitch, or heave—would most directly cause the measured depth to go up and down even if the actual tank content stayed the same.

✅ Before You Answer

• Identify which of the answer choices refers specifically to vertical motion of the MODU, not just tilting side‑to‑side or fore‑and‑aft. • Confirm whether sparks are a realistic concern with a normal sounding tape in this context or if that is a distraction. • Decide which factor (open time of tube vs. motion effects) would be the primary reason instructors emphasize lowering and retrieving the tape smartly on a floating unit.