Monitoring Systems

Monitoring systems are the ship’s continuous health check, and their value depends on the measurement chain being trusted. An alarm list that no longer matches the system, a temperature sensor fitted to the wrong depth or a viscometer that has drifted all produce confident wrong answers, and those are more dangerous than no answer at all. The guides below set out what each measurement is for, what it must be compared against, and how each one is proved.

Key facts and acceptance criteria

The values below decide whether a system passes at survey and at maintenance. They come from the maker documentation and the applicable rules, not from general practice.

Guides in this group

• Alarm Monitoring Systems (AMS) — Engine room alarm monitoring systems: alarm list verification, priority and delay settings, deadband testing, call system and alarm history records.
• Cylinder Temperature Monitoring Systems — Cylinder temperature monitoring: exhaust gas and jacket coolant temperature sensing, cylinder condition trending and alarm setpoint verification.
• Bearing Temperature Monitoring Systems — Bearing temperature monitoring: probe and RTD sensor verification, setpoint and trip proving, thermal imaging checks and bearing fault indication.
• Pressure Monitoring Systems — Pressure monitoring systems: lube oil, fuel oil, air, steam and hydraulic pressure transmitters, switch calibration, alarm and trip proving.
• Refrigeration Plant Monitoring Systems — Refrigeration plant monitoring: suction and discharge pressure, refrigerant temperature and level, capacity control, alarm and defrost control testing.
• Fuel Monitoring and Viscosity Control Systems — Fuel viscosity and flow monitoring: inline viscometer calibration, fuel conditioning and heating control, flow measurement, density compensation and alarms.
• Shaft Power and Torque Monitoring — Shaft power and torque monitoring: torque meter calibration, torsional vibration checks, thrust and power measurement, trend analysis and alarm testing.
• Exhaust Gas Temperature Monitoring Systems — Exhaust gas temperature monitoring: per cylinder exhaust gas deviation, turbocharger and injection condition trending, alarm and trip verification.
• Bearing Wear and Crankcase Pressure Monitoring — Bearing wear and crankcase pressure monitoring: wear debris detection, sump pressure and depression monitoring, oil mist and bearing condition trending.
• Crankcase Oil Mist Detection Systems — Crankcase oil mist detection: sampling head service, concentration calibration, alarm and shutdown proving, and crankcase atmosphere safety management.

How Seanav Marine services this group

Each guide in this group follows the same method, so the work is predictable and the record is comparable between visits and between vessels.

1. Scope confirmation. The vessel particulars, the equipment identity, the maker documentation, the class survey plan and the access window are established before anyone boards.
2. As-found capture. The existing configuration, settings and condition are recorded before anything is changed, so the record shows what was found and not only what was done.
3. Proof against criteria. The functions are proved against the maker and class acceptance criteria, not against an operational impression, and the test conditions are recorded with the results.
4. Restore and document. The approved settings are restored, the critical proving tests are repeated, and the report is issued with the as-found and as-left values and the outstanding defects.

A service report records the work performed and the observed results. It does not by itself issue or renew a statutory certificate, and it does not imply direct OEM agency or universal class approval.

Scope, parts and attendance depend on the equipment identity, the access, the engineer availability and the confirmed job. Send the vessel name and IMO number, the port, the ETA and ETD, the equipment maker and model, the fault description and any alarm screenshots or logs.

Frequently asked questions

How do you know a monitoring measurement can be trusted?

By proving the measurement chain rather than the reading. Simulate the input, verify the alarm and the action, and then cross-check the result against an independent measurement or the maker reference data.

Why does an alarm list matter so much?

Because the watchkeeper response plan is written around it. If the priorities, delays and texts on the system differ from the approved list, the response plan no longer matches what the panel shows.

Can a sensor be replaced with an equivalent make?

Only if the maker documentation permits it and the measurement characteristics are equivalent. A substitute that reads differently is not equivalent, and it breaks the comparison with the baseline and the maker limit.

Reference framework

These sources explain the relevant regulatory context. They do not replace the installed equipment manual or prove the applicability of a particular rule to every vessel.

• IMO: SOLAS convention and chapter scope
• IMO: MSC resolutions and circulars
• IACS: Unified Requirements index

Related: Marine automation directory · Contact the operations desk

service@seanav.org · +971 58 568 1197 · Contact the operations desk