🔍 Key Concepts

• Butterfly valve vs. gate valve design (disc in the flow vs. rising wedge/gate) • How many turns or degrees of movement are needed to go from fully open to fully closed • Typical uses of butterfly valves on cargo and ballast systems

💭 Think About

• Think about which type of valve can be moved from fully open to fully closed with the least amount of motion by the operator • Consider which valve type is best suited for situations where you must shut off or open flow rapidly in an emergency • Ask yourself: does a butterfly valve completely clear the flow path when open, or does something still sit in the stream?

✅ Before You Answer

• Verify which valve type is usually quarter‑turn (90°) vs. multi‑turn operation • Check whether a butterfly valve leaves a disc in the flow even when fully open • Confirm whether a butterfly valve is typically used for on/off and relatively quick operation rather than fine, precise throttling