An auxiliary generating set is the standby power for the vessel, so its protective chain has to be independent of the control system that starts and loads it. The safety shutdown system covers the protective functions that stop the engine: overspeed, low lubrication pressure, high coolant temperature, high oil temperature and the fuel trip. Testing proves the chain to the fuel actuator, not merely the alarm.
Key facts and acceptance criteria
The table below lists the values that decide whether the system passes at survey and at maintenance. They come from the maker documentation and the applicable rules, not from general practice, and they are the numbers a surveyor checks.
| Parameter | Requirement | Reference |
|---|---|---|
| Overspeed trip | Independent of the starting and loading control | SOLAS II-1/26 |
| Low oil pressure trip | Per the maker trip delay and setpoint | Maker technical manual |
| High coolant temperature | Alarm and trip per the maker arrangement | Maker technical manual |
| Fuel trip device | Approved device acting directly on the fuel | SOLAS II-1/30 |
| Emergency shutdown | Stops the set without relying on the control system | SOLAS II-1/34 |
Regulatory and technical basis
SOLAS Chapter II-1 regulations 26, 30 and 34, the maker technical manual for the genset protection arrangement, and the class survey plan. Trip settings come from the maker and are not adjusted to suit operating conditions.
What the service assessment covers
Seanav Marine provides independent service assessment. The following items define a starting scope for a competent service assessment. The actual test method and acceptance criteria come from the installed equipment documentation and the agreed job scope.
- Overspeed, oil pressure and temperature trip function testing
- Fuel trip device and emergency shutdown chain verification
- Protection relay and sensor calibration check
- As-found trip setting record and comparison with the maker schedule
- Proof that the set can restart cleanly after a trip, within the maker procedure
How the work is planned and executed
- Settings review. Obtain the maker trip schedule and confirm which functions are set to trip and which to alarm, and how the reset is arranged.
- Chain proof. Prove each protective function to the final fuel actuation, including the reset and the condition that allows a restart.
- Restart check. Demonstrate a clean restart after a simulated trip, and confirm the alarm annunciation and the record of the trip cause.
- Certification of settings. Issue the as-found and as-left trip record with the proving results, restoring all approved settings before the set is released.
Failures that must be distinguished before testing
Do not widen a setpoint or suppress an indication without an engineering assessment. The following failure modes have to be separated from a genuine plant fault before a conclusion is drawn, because they are common, they are visible, and they are usually the cheaper explanation.
- Trip settings changed to allow a set to keep running after a marginal cooling fault
- Emergency shutdown chains that rely on the control system that is the thing they are protecting against
- Protection relays that trip correctly but leave the set unable to restart because the reset is not in the agreed place
Equipment and OEM compatibility
Replacement parts and calibration methods must come from the original manufacturer. Seanav Marine works with Caterpillar and Cummins genset protection, Woodward and Kongsberg overspeed trips, Siemens and ABB genset control, and maker-specific engine safety modules. and sources parts through authorised distributor channels.
Frequently asked questions
Why must the auxiliary shutdown system be independent?
The auxiliary set is the vessel’s standby power. If its protection depends on the same control system that could fail, the protection fails with it. The shutdown path therefore uses separate sensing, separate supply and a direct fuel actuation.
Which trips are usually fitted on an auxiliary genset?
Commonly overspeed, low lubrication pressure, high coolant temperature, high oil temperature and a low fuel oil pressure or fuel leak trip. The fitted set comes from the maker and the approved design.
Can a trip be bypassed for a trial run?
Only under a written maker or class-approved procedure with an alternative protective measure in place. A permanent or undocumented bypass is a serious finding and is normally raised as a deficiency.
What does the test record need to show?
The trip function, the as-found and as-left settings, the proving method, the restart condition and a confirmation that the approved settings were restored.
Reference framework
These sources explain the relevant system or regulatory context. They do not replace the installed equipment manual or prove the applicability of a particular rule to every vessel.
service@seanav.org · +971 58 568 1197 · Contact the operations desk
About this guide
Published by Seanav Marine. Editorial and source review: . This general service guide is based on the references shown; it is not a signed vessel-specific engineering procedure. Equipment manuals and the responsible technical personnel determine the job requirements.
For technical assessment or a factual correction, contact Seanav Marine with the equipment identity and supporting documents.