Free OUPV Vessel Seamanship and Maneuvering Questions and Answers 1 — Questions and Answers
Question 1: You are operating a single-screw vessel in a narrow channel, proceeding parallel and close to the starboard bank. Which hydrodynamic forces should you expect to affect your vessel?
- The entire vessel will be pulled directly sideways into the bank.
- The stern will be pushed away from the bank, and the bow will be pulled toward it.
- The bow will be pushed away from the bank, and the stern will be pulled toward it. (Correct answer)
- The vessel's speed will increase significantly without a change in engine RPM.
Correct answer: The bow will be pushed away from the bank, and the stern will be pulled toward it.
This scenario describes the combined phenomena of bank cushion and bank suction. Water displaced by the bow becomes compressed against the nearby bank, creating a high-pressure cushion that pushes the bow away. Simultaneously, the accelerated flow of water into the propeller in the restricted space between the stern and the bank creates a low-pressure area, sucking the stern inward.
Question 2: When anchoring in moderate weather, what is the generally recommended minimum scope, which is the ratio of anchor rode length to the sum of water depth and the vessel's freeboard?
- 5:1 to 7:1 (Correct answer)
- 2:1 to 3:1
- 10:1
- 3:1 to 4:1
Correct answer: 5:1 to 7:1
A scope of 5:1 to 7:1 is the standard recommendation for ensuring the anchor has the proper angle of pull to dig in and hold effectively in typical conditions. A shorter scope might be used for a brief stop in calm weather but is insufficient for reliable holding. A longer scope (10:1 or more) is reserved for heavy weather or poor holding ground.
Question 3: While operating in large following seas, your vessel is suddenly thrown sideways by a wave, becoming parallel to the wave crests and placing it in extreme danger of capsizing. This dangerous situation is known as:
- Pitchpoling
- Broaching (Correct answer)
- Heaving-to
- Surfing
Correct answer: Broaching
Broaching occurs when a vessel's speed matches the wave speed, causing a loss of steerage as it surfs down a wave face. The stern is then pushed by the wave, causing the vessel to yaw uncontrollably and end up beam-on to the seas, where it is vulnerable to being rolled over by the next wave.
Question 4: Which of the following most accurately describes the effect of 'transverse thrust' (or 'propeller walk') on a single-screw vessel with a right-handed propeller?
- In reverse, it tends to push the stern to starboard.
- In forward gear at cruising speed, it strongly pushes the bow to port.
- It has no noticeable effect on vessel handling at low speeds.
- In reverse, it tends to push the stern to port. (Correct answer)
Correct answer: In reverse, it tends to push the stern to port.
A right-handed propeller (which turns clockwise in forward gear when viewed from the stern) creates a sideways force, especially at low speeds. In reverse, this force is most pronounced and consistently 'walks' the stern to port. This predictable effect is often used by skilled operators for close-quarters maneuvering.
Question 5: You are docked starboard side to a pier. A strong wind is blowing directly against your starboard beam, pinning the vessel to the dock. Which of the following is the most effective method to get underway?
- Rig an after bow spring line, turn the rudder hard to starboard, and apply a short burst of forward power to pivot the stern out. (Correct answer)
- Put the engine in full reverse to try and pull the stern away from the dock.
- Rig a forward quarter spring line and use forward power to pull the bow away from the dock first.
- Cast off all lines simultaneously and use full reverse power.
Correct answer: Rig an after bow spring line, turn the rudder hard to starboard, and apply a short burst of forward power to pivot the stern out.
Rigging an after bow spring line (from a bow cleat to a point aft on the dock) creates a pivot point. With the rudder turned away from the dock (starboard) and a brief application of forward power, the propeller's thrust will push the stern away from the pier. Once the stern is clear, the spring line can be released and the vessel can back away.
Question 6: When towing another vessel, what is the primary purpose of maintaining a sag, or 'catenary,' in the towline?
- To keep the line from fouling in the propeller.
- To shorten the effective length of the tow for better control.
- To act as a shock absorber against sudden loads. (Correct answer)
- To reduce the overall drag of the towline in the water.
Correct answer: To act as a shock absorber against sudden loads.
The weight of the towline creates a natural sag known as a catenary. This curve acts as a spring or shock absorber, dampening the shock loads that occur as the two vessels pitch and surge in a seaway. This prevents sudden, powerful jerks that could part the line or damage deck fittings on either vessel.
Free OUPV Vessel Seamanship and Maneuvering Questions and Answers 1
You are operating a single-screw vessel in a narrow channel, proceeding parallel and close to the starboard bank.
Which hydrodynamic forces should you expect to affect your vessel?