Uncontrollable Forces

Cannot be controlled by the shiphandler, but must be weighed up and/or exploited

1. Wind
2. Sea State
3. Current
4. Shallow Watter effect/ Squat

Can be controlled by the shiphandler

LATER

Lines

   Anchors

Tugs

                     Engines (propellers)

    Rudder

Controllable Force

Propellers

• Most important FORCE on ship

• Most have ships have 2
• Aircraft Carriers/Patrol Craft have 4
• Frigates have 1

• Result of propeller spinning on its shaft
• Caused by pressure differential between opposites of prop blade

1. Suction Current- Going into propeller
2. Discharge Current (Prop Wash)

• Causes stern to move sideways in the direction of propeller rotation

The slower the ship moves through the water, the greater the effect of side force

CPP

Controllable Pitch Propeller

• Eliminates requirement for reversal of shaft direction
• Rotates prop blades to cause reversal of pitch
• Used aboard ALL US Navy Gas turbine and Diesel Ships
• Normally never affected by Side Force

• Port engine ahead
• CCW
• Sterns walks to left

• Port engine back
• CW
• Stern walks to right

1. Command
2. Reply
3. Report
4. Acknowledgement

1. Direction
2. Ammount of rudder                                                                    Standard =15*                                                                      Full= 30* (25* on YP)                                                    Hard=35* (30* on YP)                                                     
3. Course to steer

Conn: "Come right steer course 130 degrees true"

1. Engine Desired
2. Direction Desired
3. Bell Desired
4. Exact speed and/or revolutions

1. Port back 1/3
2. Starboard Ahead 1/3
3. Left Full Rudder

1. Starboard back 1/3
2. Port Ahead 1/3
3. Right Full Rudder

1. Put rudder over full toward side man went over
2. All engines ahead full
3. When abeam, stop inboard engine
4. Create Lee

Fastet method

1. Put Rudder over full toward side man went over
2. All engines ahead full
3. When heading is 60 degrees off original couse, shift rudder and steady on reciprol of oc
4. Create Lee

Easier, but slower

1. Put rudder over full toward side man went over
2. All engines ahead full
3. Continue at full rudder until on recipriocal of orignal course
4. Steady for a distance that will give a good "run" at the man
5. Full rudder to the man