Controllable Pitch Propeller

Question 1

State the locations and functions of the HPU and OD box in the CPP system.

Answer 1

Hydraulic Powerpack Unit (HPU): Contains hydraulic oil required to change CPP pitch and is the central controller of the CPP system. Location - Port and Stbd Shaft Alley

Oil Distribution (OD) box: Distributes hydraulic oil to CPP hub.
Location - Port and Stbd Shaft Alley

Question 2

State the locations and functions of the gravity tank and drain in the CPP system.

Answer 2

Gravity Tank: Maintains static pressure in the hydraulic oil to counter outside S/W pressure, preventing S/W from entering CPP system.
Location - Port & Stbd OPS platform

Drain: When the CPP system is running, leaking hydraulic oil is collected in the drain to prevent net loss of oil. This is crucial as the hydraulic oil system is a closed system.
Location - Port & Stbd Shaft Alley

Question 3

State the functions of the pumps in the CPP system.

Answer 3

P1 and P2: Main pumps in the CPP system, pressurize the hydraulic oil to adjust the propeller blades and change CPP pitch.
P3: Maintains a certain level in the gravity tank so that it can deliver the desired static pressure.
P5: Returns the hydraulic oil in the drain to the CPP system when the oil in the drain reaches a certain level which is determined by a sensor.

Question 4

Describe the flow of hydraulic oil from the HPU to the CPP.

Answer 4

HPU ⇒ P1 & P2 ⇒ OD box ⇒ Shaft ⇒ CPP hub

Question 5

State Tiers 1 & 2 of Control Points and their locations for the CPP p/ps.

Answer 5

Tier 1: Pump starter panels in the Shaft Alley
Tier 2: SCMMS in MCR

Question 6

State Tiers 1 to 4 of Control Points and their locations for the CPP Pitch.

Answer 6

Tier 1: HPU in Shaft Alley
Tier 2: CPP LOP on M/E LOP in E/R
Tier 3: PCMS in MCR
Tier 4: Throttle Lever at MCR/Bridge

Question 7

State the 5 pre-start checks before starting the CPP.

Answer 7

1. Check hydraulic tank oil level with the black dipstick at the centre of the HPU
2. Ensure emergency hose connection valve v22 is closed
3. Check and open valve to all gauges and sensors
4. Set local/remote switch on pump starter panel to:
   “LOCAL” position for LOP (Pump Starter Panel) starting of pumps
   “REMOTE” position for SCMMS (pg 16) starting of pumps
5. Set P3 and P5 pumps to “RUN” position

Question 8

State the 5-step start up procedure of the CPP on the HPU and CPP LOP.

Answer 8

1. Set P1/P2 to “LOCAL”
2. Switch P1/P2 to “START”
3. Check oil pressure displayed on CPP HPU
   4i. HPU: Set HPU to “LOCAL”,
   4ii. CPP LOP: Set HPU to “REMOTE”, CPP LOP to “LOCAL”
4. With shaft at standstill, manoeuvre through buttons while observing pitch on pitch scale.

Question 9

State the 4-step start up procedure of the CPP on the PCMS and the Throttle Lever.

Answer 9

1. Set P1/P2 to “REMOTE”, HPU to “REMOTE”, CPP LOP to “REMOTE”
   2a. PCMS: Set PCMS to “SEMI”
   2b. Throttle Lever: Set PCMS to “AUTO”
2. On SCMMS pg 16, click on P1/P2, and F1/Start.
3. With shaft at standstill, manoeuvre through buttons/lever while observing pitch on pitch scale.

Question 10

State the 2 locations where shutdown can occur and their shutdown procedures.

Answer 10

At CPP LOP:
1. Set HPU “REMOTE”, CPP LOP “LOCAL”
2. With shaft at standstill, manoeuvre through buttons/lever until zero pitch. Observe zero pitch indicator light.
3. Set P1/P2 PSP to “LOCAL”
4. Switch P1/P2 “STOP”

At PCMS:
1. Set P1/P2 PSP “REMOTE”, HPU “REMOTE”, CPP LOP “REMOTE”, PCMS “SEMI”
2. With shaft at standstill, manoeuvre through buttons/lever until zero pitch. Observe via SCMMS pg 16.
3. On SCMMS pg 16, click on P1/P2 F2/Stop.

Question 11

Whats the difference between the “parallel” configuration and the “cross” configuration?

Answer 11

What does once pressurized is now being depressurized and vice versa.

Question 12

State the parameters of the CPP System:
Pitch setting time
P1/P2 max working p
P3 static p
Auxiliary s/w p/p p
Servo (S) p/p capacity
Booster (B) p/p capacity
OD box high oil temp
Propeller diameter
Propeller blades
Direction of Port M/E Propeller input and output
Direction of Stbd M/E Propeller input and output

Answer 12

Pitch setting time: 18s to get from full ahead to full astern with P1+P2
P1/P2 max working p: 70 bar/7 Mpa (1-5 bar when running but not pitching)
P3 static p: 1.5 bar
Auxiliary s/w p/p p: 1-2 bar
Servo (S) p/p capacity: 18 ℓ/min
Booster (B) p/p capacity: 31 ℓ/min
OD box high oil temp: 65°C
Propeller diameter: 3000mm
Propeller blades: 5
Port M/E -> Propeller: CW input -> ACW output
Stbd M/E -> Propeller : ACW input -> CW output

Question 13

Explain which pumps have servo and booster pumps.
Explain servo and booster pumps.

Answer 13

Both p1 and p2 are dual gear p/ps, and will have both servo and booster pumps
Booster p/p will cut in when the system deems that it cannot go from ahead to astern in 18s and increase the hydraulic oil pressure. Otherwise, only servo p/p will run.

Question 14

State the 3 things the auxiliary S/W p/p cools and the S/W cooling start-up procedure.

Answer 14

Hydraulic oil in the system
Shaft seal
Plummer box bearing

1. Open the following valves:
   Inlet/Outlet valve for p/p
   Suction valve in shaft alley (lever type)
   O/B valve
2. Switch the auxiliary s/w p/p to “START” on its LOP

Question 15

State the 4 step procedure to control pitch of the CPP in an emergency.

Answer 15

1. Open the suction valve located below the HPU
2. Isolate the controller box valve
3. Open left top and right bottom to go ahead OR left bottom and right top to go astern
4. Manually turn the hand crank

Question 16

State the drain tank capacity and drain pump capacity.

Answer 16

Drain tank capacity: 40L
Drain pump capacity: 13L/min

Question 17

State the power pack oil tank capacity and the gravity oil tank capacity.

Answer 17

Power pack oil tank capacity: 600L
Gravity oil tank capacity: 55L