Ch. 1 Flashcards
T or F In day-to day work, the most useful unit of measurement for estimating turning circles and other distances is the ship’s own length.
True
In shallow water, a ship’s turning circle is ________.
Larger
An average-size ship turning circle is usually slightly ________ when the ship turns to the right than when she turns left.
Larger
A VLCC’s turning circle to the right is usually ________ her turning circle to the left.
Nearly the same as
When revolutions are increased during a turn the tactical diameter becomes _________.
Smaller
For a given rudder angle and engine speed, the rate of turn _______ as the depth of the water decreases.
Does not change
T or F A ship can be backed and filled in the smallest are when turned to the left.
False
You are aboard an average-size, loaded, aft house tanker proceeding through open roadstead. Wind blowing hard enough to overcome twisting effect. When you back your ship you would expect her to
Head into the wind while she has headway and back into the wind when she has sternway
Assuming there are no extraordinary wind, current, or bank effects, a ship should be swinging moderately to __________ before her engine is put astern.
Port
A bowthruster is sometime preferable to tugs because
It is located at the extreme ends of the vessel
available at all times
Good lateral control
Save on expenses for tugs
What are the disadvantages of bowthrusters
ineffective at high speed less powerful than tug can not slow or hold against current unusable at light drafts require maintenance
Bow thrusters are usually quite effective at speeds up to 5 knots
False
The concept of using the most effective maneuver is important because
- The ship is maneuvered using the minimum number of engine and rudder orders
- Several tasks are accomplished simultaneously
How would you expect the following shiphandling characteristics to change as your ship moves from deep to shallow water
- Tactical diameter will increase
- twisting effect when backed will increase
- Rate of turn no significant change
- Speed loss during large course changes decrease
- speed loss when engine stopped Increase
- Directional stability Increase
How would you expect the following to effect directional stability?
Increased length- more positive
increased beam - less positive
Increased drag - more positive
Decreased UKC - more positive
Increased block coefficient - less positive
more full sections forward - less positive
Increased rudder angle-
Ship trimmed by the head - less positive
increased squat by the head - less positive
T or F Ships with large block coefficients are more likely to trim by the head in shallow water.
True
Which of the following statements is/are true for ships with negative stability?
A larger rudder angle is needed for longer periods of time to start a turn
A larger rudder angle is needed for a longer period of time to steady up after a turn
The ships rate of turn increases when the rudder is put amidships during a turn
T or F The only effective way to slow a ship is to stop the engine and, if necessary, go astern
False
A VLCC makes a hard over turn. You would expect her to lose nearly ______% of her headway when her heading changes by 90 degrees
25%-30%
In a crossing situation where collision exists what might be a good option other than backing in order to slow down?
Make a round turn
A combination pilot ladder/accommodation ladder is required when the distance from the water to the top of the water exceeds ____ feet.
30
T or F A modern container ship has more sail area than a full rigged sailing ship?
True
Mathmatically when will shallow water effect become significant?
Depth = 1.5 x Draft
Mathmatically when will shallow water effect be felt?
Depth = 1.2 x Draft
