Under way, with the thermographer on board. A ship’s main switchboard, propulsion supplies and hotel services only carry their real load at sea, so that is when a poor connection shows. The survey works round the ship’s routine, with the crew opening panels one at a time, and each finding is located by switchboard, panel and circuit for the ship’s engineers.
Why at sea and not in port?
Thermography finds a poor connection by the heat it gives off when current flows through it. Alongside, a ship may be on shore power or running fewer generators, and in dry dock most of the installation is carrying little or nothing. Under way, the generators, propulsion supplies, galley, HVAC and accommodation are all working. That is the load the survey needs to see (see what load a survey needs).
What the survey should cover
- Main and emergency switchboards: incomers, bus sections, breakers and outgoing ways.
- Propulsion and HV equipment: imaged through infrared windows where they are fitted, or as far as the ship’s procedures allow. Nothing is opened that the chief engineer has not agreed (see when infrared windows are worth fitting).
- Motor control centres and starters for pumps, fans, compressors and steering gear, with the equipment running.
- Hotel services: galley and laundry supplies, HVAC and refrigeration panels, and the distribution boards serving accommodation decks.
Working round the ship’s routine
A building has an FM manager and a permit system. A ship has a chief engineer, an electro-technical officer and a watch system. The survey plan is agreed with them before departure: which spaces, in what order, and at what times of day the relevant equipment is busiest. Galley supplies are imaged around meal service; engine room switchboards when the ship is at sea speed. Covers come off one at a time, opened by the ship’s authorised crew, and go back on before the next one comes off (see who opens the panels).
What changes on a ship
- Load moves. Generators are brought on and off line as demand changes, so the report records the operating state with each image.
- Warm surroundings. Engine room ambient is high and some equipment runs warm by design. Findings are judged against a matching reference, not against the room.
- Reflections. Bare metal and polished panel fronts reflect heat from nearby machinery, so suspect readings are checked from a second angle.
- Motion. A rolling ship makes steady imaging harder, so the thermographer takes the time to get a sharp, measurable image rather than a quick one.
What the ship gets
A report that locates each finding by switchboard, panel, circuit and phase, with the measured temperature, the difference in °C from its reference and the operating state at the time. Ti inspects and reports; the ship’s engineers or the owner’s contractor decide on and carry out any work, usually at the next suitable port call or planned maintenance window (see after a survey finds a hot connection).
Why load matters
On a London data centre build, commissioning thermography by our team found 16 busbar sections reading above 80 °C under test load, the highest 103.5 °C at a tap-off unit. They showed because the system was carrying load when it was imaged. A ship is the same: survey it while it is working.
Frequently asked questions
Can the survey be done in dry dock instead?
Dry dock is a good time to fix findings, but a poor time to find them, because the installation is lightly loaded. Survey at sea first, then use the dry dock or port call to put things right.
How long does a ship survey take?
It depends on the size of the ship and how much of the installation is in scope. On larger passenger ships the thermographer may sail for a full passage between ports, working round the ship’s routine.
Does the survey interrupt the ship’s operation?
No. Thermography is non-contact and is carried out with systems running. Panels are opened only by the ship’s authorised crew, one at a time, where it is safe.
Related reading
- What a thermography survey can’t detect
- Refrigeration plant and cold store panels
- Compressed air plant in an electrical survey
- Data centre electrical thermography
- Switchgear thermography
- Annual PPM electrical thermography
- 7 electrical risks thermography finds
Ti Thermal Imaging’s surveys are carried out by ITC Level 3 thermographers, and Ti is a Level 3 certified company. Our work has featured on BBC News and ITV.
Talk to us: +44 20 3885 7464 · sales@thermalimaging.co.uk · contact page
About the author: Rachael Browning, General Manager, Ti Thermal Imaging.