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Washington / SEAPA Pilots > Hooyer > Flashcards

Hooyer Flashcards

1
Q

The position of the __________ plays a crucial role in explaining ship behavior.

A

Pivot point

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2
Q

True / False
We can not move a ship sideways without rotational motion.

A

True
pg 8

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3
Q

The moment of a force about a point is the product of that force and ____________________.

A

The perpendicular on its line of action.

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4
Q

Momentum is the quantity of motion measured by the product of mass and __________.

A

Velocity
Pg 8

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5
Q

True / False
Frictional drag has relatively less retarding effect on bigger ships.

A

True
Big ships sustain speed because of the relatively small wetted area and lower frictional drag.
Pg 9

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6
Q

When ship’s momentum acts as a force the ___________ is the pt of impact of that force.

A

Center of gravity

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7
Q

The magnitude of longitudinal and lateral resistance depends on what?
(Two things)

A

Ships speed and shape
Pg. 11
They are directly proportionate to ship’s prop force at a constant speed.

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8
Q

Force exerted a ship will result in motion only after _______ has been overcome.

A

Inertia
Pg 11

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9
Q

True / False
A beam wind meets lateral resistance where a beam current does not.

A

True
Pg. 11

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10
Q

When birthing big tankers the sim is to obtain a singular ___________ motion and prevent __________ motion the moment of making contact on the dock.

A

Lateral motion
Rotational motion
Pg. 12
Easier to check lateral motion.

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11
Q

Rudder and propeller produces a combination of ______ motions. A. 1 B.2
C.3 D. 4

A

C. 3
Pg.12

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12
Q

What are the three motions a propeller and rudder produce?

A

Lateral, longitudinal and rotational
Pg. 12

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13
Q

The direction of ________ motion of the ship determines to a very large extent the position of the pivot pt.

A

Longitudinal
Pg. 13

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14
Q

1 ton of bollard pull = ________ HP

A

100 HP

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15
Q

Longitudinal resistance = _____ % of propulsion force under constant speed.

A

25 %

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16
Q

Transverse force of propeller working astern = _____ % of applied stern power.

A

5 - 10 % applied stern power.

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17
Q

Rotational motion is about a ____________ axis and is influenced by ship’s shape, motion, magnitude and point of impact of various forces.

A

Vertical the top of the vertical axis can be considered the pivot pt spot.

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18
Q

True / False
Frictional drag has no effect on the position of the pivot point.

A

True
Pg. 17

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19
Q

The position of G is indicated by _____________ .

A

Trim. Only when on even draft is the G at the center.
Pg. 17

20
Q

When a ship makes a turn what happens to the pivot point?

A

The pressure pushes the pivot point closer to amidships.

21
Q

What does the pressure aft of the pivot point do to the drift angle?

A

Limits the drift angle.

22
Q

On a directionally stable ship what happens to the turn when the rudder is placed amidships?

A

The turn will stop or slow down.

23
Q

Two tugs push on a ship under headway (fwd motion) which tug has more leverage?

A

The aft tug and creates rotational motion.

24
Q

True / False
As long as the center of wind pressure (P) is not above the Center of Underwater Resistance the wind will turn the ship.

A

True

25
Q

How can transverse winder force be counteracted when forward momentum is causing an angle with intended course?

A

Use transverse force aft - rudder force.
Pg. 20

26
Q

True / False
Rudder force has no effective leverage when backing.

A

True
Pg. 20

27
Q

True / False
When making Steinway the bow has a tendency to seek the wind.

A

False, the stern seeks the wind.
Pg. 20

28
Q

True / False
Transverse thrust of a right hand propeller can easily be overcome by a strong wind on the starboard bow.

A

True
Pg. 20

29
Q

When making a turn underway lateral resistance forward that develops on the exposed bow as the swing sets in acts in the ________ direction as the transverse component of rudder force.

A

Opposite direction .
Pg. 21

30
Q

When the ship is dead in the water what causes it to resist acceleration?

A

Inertia
Pg. 21

31
Q

The longitudinal propulsion force is concurrently working to overcome _________ when part of this force is converted into transverse rudder force.
A. Longitudinal Inertia B. Lateral Inertia C. Rotational Inertia D. All of the above.

A

D. All of the above
Pg. 21

32
Q

True / False
The rudder force overcomes lateral inertia of the vessel sooner than propeller force overcomes longitudinal inertia.

A

True.
Pg. 21

33
Q

With a ship DIW the pivot point for a L to B ratio of 8 is _____ when initially having fwd motion.

A

1/8 L from the bow.
Pg. 21

34
Q

The rudder works at max leverage when ____________.

A

Vessel is starting from DIW

35
Q

When the underwater resistance reaches a magnitude of about 1/4 of the prop force the pp moves away from the fwd position proportionally at _____ x the magnitude of force.

A

1 x magnitude

36
Q

If the pp initially is 1/8 where does it move back to when the resistance reaches 1/4 of the prop force? When turning at a constant speed?

A
  1. 1/4 L
  2. 11/32 L
37
Q

When on a straight course with no lateral resistance where is the pp? What happens in a turn? What happens to the lever arm?

A
  1. 1/4L
  2. It’s pushed back to 11/32L
  3. It’s shortened
    Pg -22
38
Q

A ship under way under rudder turning has its pp where?

A

1/3 L
Pg 22

39
Q

The position of the actual pp is determined by
A. L/B ratio
B. Longitudinal motion
C. Trim
D. All of the above

A

D. All of the above

40
Q

From a position DIW with full rudder it is easier to overcome ________ inertia then ________ inertia.

A

1.Rotational
2. Longitudinal

41
Q

_______ inertia helps us make a tight turn.

A

Longitudinal pg 23

42
Q

The magnitude of the rotational momentum introduced upon a ship depends on what?

A

Ships mass
P 23

43
Q

True or false
Once rotational momentum has developed the influence of a newly introduced force acting on the ship has no immediate affect on pivot point.

A

True
P24

44
Q

The quickest way to stop a swing of a loaded tanker going astern is ________.

A

Bow thruster or tug due to rotational inertia to overcome by prop force.
P 24

45
Q

On ships with relatively big propellers a turn in what direction is smaller?

A

Port
P25

46
Q

Larger diameter propellers of low speed revolutions have more/less transverse thrust when working astern?

A

More p25

Washington / SEAPA Pilots (4 decks)

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