Shiphandling

Question 1

When turning in shallow water the diameter of the turn will ______ ? By how much?

Answer 1

<p>Increase. By twice the diameter.</p>

Question 2

What happens to rate of turn in shallow water verses deep water?

Answer 2

<p>Remains constant, though turning circle (tactical) diameter increases in shallow water.</p>

Question 3

Is transverse thrust while moving ahead more noticeable on a small or large ship

Answer 3

<p>Small, until almost no effect on ULCC and VLCC sized ships.</p>

Question 4

If accelerating will turning circle diameter be larger or smaller than at constant RPMs.

Answer 4

Smaller. (Rule of thumb: Starting DIW with turns for 6 kts, turning circle will be 1/2 size of circle starting at 6 kts with constant RPM)

Question 5

At what speed through the water does a bow thruster become effective?

Answer 5

Two knots.

Question 6

At what depth do shallow water effects take place?

Answer 6

Depth of 1.2 to 1.4 of draft

Question 7

In shallow water does ship become more directionally stable? Steering improves?

Answer 7

Yes

Question 8

Does turning circle diameter increase or decrease with shallow water effects?

Answer 8

Increase

Question 9

Does the ship twist more or less when backed in shallow water?

Answer 9

More

Question 10

Does a ship carry further or shorter in shallow water?

Answer 10

Further

Question 11

What direction from the wind does the bow tend when backing?

Answer 11

Bow falls away and ship will back into the wind. Due to pivot point moving aft.

Question 12

As a ship reduces speed it will tend to turn in what direction relative to the wind?

Answer 12

It will turn into the wind.

Question 13

What creates the pivot point?

Answer 13

The couple between the forward momentum of the vessel and the longitudinal resistance created by the water.

Question 14

Where is the pivot point when the vessel is at a constant speed?

Answer 14

Approximately 1/4 of the ships length from the bow.

Question 15

How does the pivot point location effect turning levers?

Answer 15

The moment of force times the length to the pivot point creates the turning lever.

Question 16

How does the excessive use of astern bells effectively put a ship ‘out of control’?

Answer 16

Leaves the ship exposed to transverse thrust, wind, tide, and bank or shallow water effect.

Question 17

How can loss of rudder control be overcome at slow speeds?

Answer 17

By using the ‘Kick Ahead’ or ‘Pumping the Rudder’ technique.

Question 18

When using the ‘Kick Ahead’ or ‘Pumping the Rudder’ technique what is important to keep in mind about rudder position?

Answer 18

Insure rudder is hard over to prevent unwanted increases in ahead motion.

Question 19

Which is more effective for ‘pumping the rudder’ or a ‘kick ahead’? A steam ship or a diesel ship?

Answer 19

A diesel ship because it comes up to speed faster.

Question 20

What safety should be used with a turbine plant?

Answer 20

Leave dead slow ahead as long as possible because plant can be slow to come on line.

Question 21

What creates transverse thrust?

Answer 21

1. Helical discharge on the port side of the rudder. 2. Upward flow from the hull puts more pressure on the downward sweeping blades.

Question 22

What direction does a right hand prop move the bow when rotating ahead?

Answer 22

Port

Question 23

What direction does a left hand prop move the bow when turning ahead?

Answer 23

starboard

Question 24

What direction does a right hand prop move the stern when turning astern?

Answer 24

Port

Question 25

What direction does a left hand prop move the stern when turning astern?

Answer 25

Starboard

Question 26

When turning ahead what direction does a right hand prop turn when viewed from astern?

Answer 26

Clockwise

Question 27

When turning ahead what direction does a left handed propeller turn when viewed from astern?

Answer 27

Counter clockwise

Question 28

What percentage of applied power will be transverse thrust?

Answer 28

5-10%

Question 29

What is the wedge effect?

Answer 29

The movement of water, from astern wheel wash, down between the ship and a solid face acting as a cushion. By backing you create a water wedge between the pier face and the vessel.

Question 30

In what direction is does the transverse thrust of a left handed controllable pitch propeller move the stern when backing?

Answer 30

To port like a right handed fixed propeller.

Question 31

Does transverse thrust increase or decrease when shrouded by a nozzle?

Answer 31

Decrease

Question 32

Where is the pivot point when dead in the water.

Answer 32

At center of underwater mass, approximately amidships depending on trim.

Question 33

Where is pivot point when initially moving ahead?

Answer 33

1/8 the ship length from the bow.

Question 34

Where is pivot point while turning when moving ahead at a constant speed?

Answer 34

1/3 of ships length from the bow.

Question 35

What is the type resistance which develops a ship to moving bodily sideways through the water?

Answer 35

Lateral Resistance

Question 36

Why are turning circles at different speeds approximately the same diameter?

Answer 36

1. Because lateral resistance and rudder force find a balance. 2. Only the rate of turn changes 3. Speed entering a turn does not increase the turning ability.

Question 37

How much of a speed reduction can be expected in a turn with constant RPMs? Why?

Answer 37

30-50% loss, due to the increase of lateral resistance due to the increase of exposed side shell.

Question 38

At what RPM is the minimum radius achieved in a standing turn?

Answer 38

Dead in the water to dead slow ahead

Question 39

What are the three different directional stability conditions?

Answer 39

1. Stable - Steadies up when rudder is put amidships 2. Neutral - Continues a swing at a steady rate with rudder amidships 3. Negative - Swings at increasing rate with rudder amidships