Which is the BEST way for a twin-screw...

🔍 Key Concepts

• Twin-screw maneuvering: How inboard vs. outboard propellers affect movement when alongside a pier • Spring lines: Difference between a forward‑spring and after‑spring and what each does to the vessel’s pivot point • Propeller wash and suction near the pier: Which propeller you most want to keep clear of the pier to avoid damage or sucking the stern in

💭 Think About

• Think about which line (forward‑spring or after‑spring) will let the stern swing away from the pier when an engine is used against it • Ask yourself: if the inboard propeller is the one closest to the pier, which engine (inboard or outboard) should be turning to move the stern out without risking contact? • Consider how using just one engine (inboard vs. outboard) changes the turning moment around the spring line and how that helps clear the inboard screw

✅ Before You Answer

• Identify clearly which propeller is inboard (closest to the pier) and which is outboard (away from the pier) in this situation • Determine what effect a forward-spring has when you go slow ahead on an engine: what part of the vessel moves, bow or stern? • Verify which option uses an engine that is away from the pier while the line used holds the bow in and lets the stern swing clear

Which is the BEST way for a twin-screw vessel to clear the inboard propeller and maneuver off a pier?

Hold the forward-spring line and go slow ahead on both engines

Hold the after-spring line and go slow astern on the outboard engine

Hold the forward-spring line and go slow ahead on the inboard engine

Hold the forward-spring line and go slow ahead on the outboard engine

🔍 Key Concepts

💭 Think About

✅ Before You Answer