DWO Ship Handling 3 — Questions and Answers
Question 1: When using an anchor to assist in turning a vessel in a confined space, which technique is employed?
- Letting go both anchors simultaneously
- Dropping one anchor and using it as a pivot point (Correct answer)
- Dragging both anchors at slow speed
- Using the anchor chain as a brake only
Correct answer: Dropping one anchor and using it as a pivot point
By letting go one anchor with a short scope, the vessel can use it as a pivot point to swing the stern around in a confined area.
Question 2: The 'transfer' during a turning maneuver refers to:
- The lateral distance moved perpendicular to the original course (Correct answer)
- The speed lost during the turn
- The distance traveled along the original heading
- The angle between original and new course
Correct answer: The lateral distance moved perpendicular to the original course
Transfer is the perpendicular (lateral) distance the ship's center moves from the original track during a turn.
Question 3: A vessel experiences 'bank suction' when:
- The anchor drags along the seabed
- The stern is attracted toward a nearby bank or shoal (Correct answer)
- The bow is pushed away from a canal bank
- Water is drawn into the engine cooling system
Correct answer: The stern is attracted toward a nearby bank or shoal
Bank suction occurs when the low-pressure area under the stern is attracted toward the near bank, causing the stern to sheer toward it.
Question 4: When overtaking another vessel in a narrow channel, the overtaking vessel should expect:
- The overtaken vessel to speed up
- Interaction forces that attract the two vessels toward each other (Correct answer)
- The overtaken vessel to move to starboard
- No hydrodynamic interaction at safe passing distance
Correct answer: Interaction forces that attract the two vessels toward each other
As two vessels pass in close proximity, interaction forces create suction that tends to draw the vessels toward each other.
Question 5: In the event of a main engine failure at sea, what is the immediate priority for ship handling?
- Broadcast a MAYDAY immediately
- Maintain course using sails if available
- Ensure the vessel is in a safe position and prevent drifting into danger (Correct answer)
- Anchor immediately regardless of depth
Correct answer: Ensure the vessel is in a safe position and prevent drifting into danger
The immediate priority is to assess the vessel's position relative to hazards and take actions to prevent grounding or collision while engineers work to restore power.
Question 6: What is the purpose of 'heaving to' in heavy weather?
- To stop the vessel completely using both anchors
- To position the vessel so it rides comfortably with minimal forward movement (Correct answer)
- To increase speed through head seas
- To deploy the sea anchor from the stern
Correct answer: To position the vessel so it rides comfortably with minimal forward movement
Heaving to presents the vessel at an angle to wind and sea that minimizes rolling and pitching while maintaining near-stationary position.
Question 7: When backing a twin-screw vessel, how is directional control primarily achieved?
- By rudder angle alone
- By differential use of the two propellers (Correct answer)
- By bow thruster operation
- By alternating ahead and astern bells
Correct answer: By differential use of the two propellers
On twin-screw vessels, steering when backing is primarily accomplished by varying the speed and direction of each propeller independently.
DWO Ship Handling 3
When using an anchor to assist in turning a vessel in a confined space, which technique is employed?