Your vessel is fitted with a Controllable Pitch Propeller (CPP). During berthing, the chief mate is on the bridge working with the pilot. Explain how a CPP differs operationally from a fixed pitch propeller and the handling implications.

A. CPP vs FIXED PITCH — OPERATIONAL DIFFERENCES AND HANDLING: FIXED PITCH PROPELLER (FPP): Engine RPM is varied to change thrust. To go astern: engine must be reversed (stopped, then turned in opposite direction). Time to achieve astern thrust: typically 45-90 seconds. The stopping manoeuvre requires engine reversal and has characteristic response time. CONTROLLABLE PITCH PROPELLER (CPP): Engine maintains constant RPM (or near-constant). Thrust direction and magnitude changed by varying pitch angle of propeller blades: (a) Full ahead pitch: maximum forward thrust; (b) Zero pitch: no thrust (propeller spinning but no axial force); (c) Full astern pitch: maximum astern thrust — achieved in seconds, not minutes. HANDLING ADVANTAGES: (1) Very fast response — astern thrust achieved without engine reversal (critical in berthing emergencies); (2) Precise thrust control — small pitch increments for delicate manoeuvring; (3) Engine runs at constant optimum RPM — better fuel efficiency. HANDLING CHARACTERISTICS TO KNOW: (1) At zero pitch the propeller still creates rotational wash — affects bow thruster effectiveness; (2) Large CPP vessels may have significant propeller walk at low pitch; (3) Crash stop procedure: move pitch to full astern — vessel stops faster than FPP because no engine reversal time. CHIEF MATE IMPLICATION: know the pitch control location on the bridge and understand that the pitch lever is the primary manoeuvring control, not the telegraph in the traditional sense.

B. A CPP operates the same as a fixed pitch propeller from the bridge perspective. The pitch adjustment is an internal engineering function and has no bearing on bridge manoeuvring technique.

C. The main advantage of CPP is that the engine can be shut down and the vessel coasted to a stop using pitch alone, without any fuel consumption during the final approach to berth.

D. CPP vessels cannot go astern without reversing the engine. The controllable pitch only adjusts fuel efficiency — astern propulsion is achieved the same way as fixed pitch vessels.

A. BRIDGE ENGINE REMOTE CONTROL — PRINCIPLES AND TESTING: OPERATING PRINCIPLE: Modern vessels have a telegraph system that allows the bridge to command propulsion from three positions: (1) Bridge wing (port and starboard); (2) Bridge centre console (primary); (3) Engine room local control (manual override). The system typically uses an electronic or electro-pneumatic telegraph — the bridge moves the telegraph lever and the engine room control room (or automated system) responds with matching engine movement. REMOTE CONTROL TYPES: (a) Bridge full control: bridge moves engine telegraph → ECR or UMS system automatically adjusts fuel injection, ahead/astern valve, and RPM; (b) Telegraphed control: bridge signals intention, engine room carries out manually; (c) CPP (Controllable Pitch Propeller): blade pitch changes rather than engine RPM — bridge pitch lever directly adjusts thrust. PRE-DEPARTURE TEST: (1) Notify engine room of impending test; (2) Test both bridge wing controls and centre console — move telegraph full range ahead/stop/astern; (3) Confirm ECR repeater matches bridge telegraph position; (4) Test emergency stop function; (5) Confirm steering gear tested (SOLAS V/26 — 12 hours before departure); (6) Log all tests with times; (7) Confirm with chief engineer "engines ready for manoeuvring."

B. Bridge engine control is tested only at drydock. Between drydocks, the engineer officer of the watch is solely responsible for engine operations and the chief mate has no role in engine testing.

C. The bridge telegraph is advisory only. The engine room carries out all engine movements independently — the bridge telegraph is a communication tool, not a control system.

D. Engine testing before departure is done by increasing to full ahead for 5 minutes then stopping. Other tests are the chief engineer's responsibility and are covered by the SMS.

A. UMS ALARM — BRIDGE OOW/CHIEF MATE RESPONSIBILITIES: UMS BACKGROUND: SOLAS II-1/46-54 and the UMS Code (MSC/Circ.645) allow machinery spaces to be operated without continuous manning when the vessel meets prescribed equipment and alarm standards. The engineer is on call, not in the machinery space. OOW BRIDGE ACTIONS ON UMS ALARM: (1) ACKNOWLEDGE the alarm on the bridge alarm panel — this stops the audible alarm but keeps the visual; (2) RECORD: alarm type, time, and acknowledge time in the logbook; (3) CONTACT the duty engineer officer — give the alarm description and location; (4) MONITOR the alarm: if a second alarm follows rapidly (cascade alarms), or if a HIGH PRIORITY alarm activates (blackout, main engine shutdown, steering failure) — take immediate navigational action as appropriate; (5) DO NOT SILENCE AND IGNORE: the alarm system requires that alarms are responded to — an unresponded-to alarm triggers escalation to the next person on the call list; (6) HIGH PRIORITY ALARMS: main engine slowdown/shutdown → notify master, consider navigational implications (vessel now drifting or under reduced power); (7) Document all alarms, response times, and engineer actions taken in the UMS alarm log. CHIEF MATE UNDERSTANDING: must know which alarms require navigational response vs engineering response.

B. All UMS alarms are exclusively the duty engineer's responsibility. The bridge OOW should silence the alarm and wait for the engineer to respond — there is no bridge action required.

C. Wake the master for every UMS alarm. Only the master has authority to decide whether a UMS alarm requires action at night — the OOW should not make this assessment.

D. UMS alarms can be safely ignored for 30 minutes before escalation. The engineer's call response time is 30 minutes under SOLAS and the OOW should not contact the engineer before this period expires.