Why the generator is checked separately
A marine generator is a small diesel engine of its own, independent of the main engine, and it is the most neglected system on most boats. At anchor the air-conditioning, watermaker, fridge and charging all run off it; on charter and gulet boats it runs almost constantly. When it fails, all comfort at anchor stops, so it needs its own assessment before purchase.
What we check on the generator
- Hours and service trail: hour meter, regular oil/filter service, any overhaul due.
- Cooling and impeller: raw-water pump, heat exchanger, water at the exhaust, signs of overheating.
- Wet exhaust and water lock: leaks, carbon build-up, back-flooding risk.
- Sound shield: insulation condition, vibration mounts.
- Electrical output: voltage and frequency stability under load, panel and transfer switch.
- Load test: where possible, air-conditioning/watermaker are switched on to see real behaviour under load.
For charter and gulet
On a commercial boat a generator failure is lost income: no air-conditioning at anchor means an unhappy charter guest. The survey shows the impeller, overhaul or sound-insulation work due soon, graded A-B-C. Plan it with the electrical survey and fleet services.
What the hour meter does and doesn't tell you
The hour meter alone does not show condition. A generator run for long hours at light load can be in worse shape than a high-hours one that was properly loaded: light load leaves unburnt fuel in the cylinders and soot in the exhaust (wet stacking).
- Hour meter matching the hours on service invoices.
- Soot and oily deposits at the exhaust outlet.
- Smoke colour and noise in the first minute from cold.
- Frequency holding steady under load.
An oil analysis tells more about the generator's internal condition than the hour meter; samples can be taken with the main engines.
How the load test is done
Running the generator off load is not enough. We bring air-conditioning, water heater and chargers on in steps and hold the load for at least 20-30 minutes. A clamp meter reads current, the panel gives voltage and frequency, and a thermal camera scans the exhaust elbow, alternator connections and the inside of the enclosure.
If frequency sags or voltage hunts under load, the cause may be the fuel system, the regulator, or a generator too small for the boat's load; the report says which is likely.
FAQ
Is the generator part of the survey?
Basic checks (running, cooling, exhaust, output) are included in the pre-purchase survey. Deep engine measurement (compression/blow-by) is coordinated with an independent engine technician.
When do I get the report?
Within 2-3 working days: 70+ pages in English, photo-documented, findings graded A-B-C.