Hooyer Flashcards
What is the scale size of manned model ships?
25:1
On manned models ship’s speed is _____ times faster.
five
About what point does rotational motion occur?
The pivot point
Does the movement of the pivot point change the lever arm for rotational force?
As the distance between the applied force and the pivot point increases, the lever arm increases and decreases. The correct answer is: Yes
Define momentum:
The quantity of motion measured by the product of mass and velocity.
M = m’ x v
also
F = m’ x v
Displacement varies with the ______ of the ship’s dimensions.
- Square
- Cube
- Fourth Power
Hooyer p. 9 The correct answer is: Number 2 Cube
Wetted area varies with the _______ of the ship’s demesions. 1. Square 2. Cube 3. Fourth Power
Hooyer p. 9 The correct answer is: Number 1 Square
What is the best method to control momentum?
Keep speed down
At low speed _____________ is responisble for most of the underwater resistance met by the vessel.
frictional resistance Hooyer p. 10
At higher speeds _________ absorbs the ship’s energy
wave making system Hooyer p. 10
Both longitudinal and lateral resistance act as forces and play a role in determining the position of the ___________.
pivot point Hooyer p. 11
Along with the magnitude of a force the ________ of a force is important.
leverage Hooyer p. 11
What are the four motions?
Longitudinal, Rotational, Lateral, Relative Hooyer p. 11
RoReLoLa
After a ship comes out of current the ___________ motion manifests itself as momentum.
relative
It is easier to stop _________. 1. rotational motion 2. lateral motion
Hooyer p. 12 The correct answer is: Number 2 lateral motion
Doppler logs may show speed _______
- through the water
- over the ground
- Both
Hooyer p. 13 The correct answer is: both
__________ is used with the foreship doppler to determine stern motion
Rate of turn indicator
Doppler logs become unreliable under ______ knots.
- one
- two
- three
- four
Hooyer p. 13 The correct answer is: Number 1 one
Angle of approach can be assessed with the _________.
compass repeater on the bridge wing. Hooyer p. 14
When navigating in a current, the speed of a head current is the difference between the doppler indicated _____ and _____.
STW and SOG
In general terms 100hp is equal to _____ ton(s) bollard pull
- 0.5
- 1
- 1.5
- 2
Hooyer p. 15 The correct answer is: Number 2 1
Longitudinal resistance is equal to _______ of propulsion force under constant speed.
- 25%
- 30%
- 35%
- 40%
Hooyer p. 15 The correct answer is: Number 1 25%
Transverse force of propeller when working astern is equal to ________ of applied power.
- 1-2%
- 2-5%
- 5-10%
- 7-15%
Hooyer p. 15 The correct answer is: Number 3 5-10%
The motion of a ship can be seen as a combination of _________, __________, and __________ motions
- Longitudinal
- Lateral
- Rotational
- Relative
Hooyer p. 16 The correct answer is:
longitudinal, lateral, and Rotational
Is the location of the pivot point constant?
Hooyer p. 16 The correct answer is: No
Does frictional drag have an effect on the location of the pivot point?
Hooyer p. 17 The correct answer is: No
What dictates the location of the pivot point?
The opposition between the center of gravity and longitudinal resitance Hooyer p. 17
In what trim condition is the pivot point most likely to be in the center of the vessel?
When on an even keel. Hooyer p. 17
What is the drift angle?
The angular difference between the heading and course over ground.
When a vessel is turning what happens to the location of the pivot point relative to its location on a steady heading?
It moves towards midships Hooyer p.17
When Making Headway it shifts aft.
What limits drift angle in a turn
The lateral resistance of the exposed side shell Hooyer p. 18
If two tugs of equal power are working at even distance from midships on a ship that is DIW what type of motion will occur? 1. Lateral 2. Rotational
Hooyer p. 18 The correct answer is: Number 1 Lateral
What can be deduced from rotation of the ship when two tugs are pushing with equal power at equal distance from midships.
The ship has longitudinal motion and therefor the pivot point has moved Hooyer p. 19