Scope starts with equipment identity, not a stock list.
We do not present a public warehouse catalogue or claim availability before the RFQ is reviewed. Instead, the supply route begins with the maker, model, part reference, technical evidence, quantity and required port or handover point. The reason is not caution for its own sake. On this equipment the model designation usually narrows a component to a family, and something else — a serial number, a build or arrangement number, a suffix, the builder named on the plate where the design house is a different company — narrows it to the machine in front of you. A catalogue that answers before that is answering a different question. The groups below and the maker pages are two ways into the same enquiry, and they are not interchangeable. A group page is the right entry when the equipment is known by what it does and the plate is unhelpful, painted over or out of reach: it asks what the component has to be identified by. A maker page is the right entry when the nameplate reads cleanly and the designation is the strongest thing you hold: it starts from the type and works outwards to what is normally requested against it. Neither is a stock list, and one request can sit under a group heading here and a designation there without becoming two. Where the difficulty is the number rather than the equipment, how marine part numbers are structured explains why several can all be correct at once.
Engine-room systems
Main and auxiliary engine parts, turbocharger components, pumps, compressors, separators, filters, heat exchangers and sealing items. Requests here turn on the plate and the position: which engine, which cylinder or bank the component came off, and whether a word like exhaust valve or piston means one item or a complete assembly. Running gear, fuel injection and turbocharging each have their own identity rules, and the guides cover them one system at a time. This is the layer that either drives the ship or keeps the thing that drives it alive, and it divides further than one page can hold: engine spare parts for the machine as a whole, piston, liner and cylinder parts for an overhaul of the running gear, turbocharger spare parts where the rotor, cartridge and nozzle ring are read from the turbocharger plate and not the engine plate, separator spare parts for purifier bowls, disc stacks and their service kits, compressor spare parts for starting-air and service-air machines, boiler and burner spare parts where the boiler plate and the burner plate are two separate plates, oily water separator parts where the plant and its oil content monitor are two separate items, heat exchanger and freshwater generator parts where the type code names the frame but never the plate count, and deck equipment and steering gear parts where the machine carries its own plate rather than the ship's. If two of those plates are within reach and it is not obvious which one owns the component, photograph both.
Fluid and process equipment
Pumps, valves, pipe-system components, filters, gaskets, seals, gauges and process instrumentation. What decides a line in this group is the duty rather than the model name: the same pump casing is built with different impeller materials, seal faces and clearances for sea water, fresh water, fuel or bilge service, and a valve is specified by line size, pressure rating and the medium it passes as much as by its maker. These are the systems that serve the drive rather than produce it, and they are where one component honestly belongs in two places at once. A mechanical seal sits inside pump spare parts when it is renewed during a pump overhaul and inside filters, gaskets and seals when it is ordered as a consumable against a service interval; the cover joint under a strainer belongs to the pipe run in valves and pipe-system components and to the consumable list in the same breath. That overlap is resolved on the enquiry, not on the page: the line is quoted against the equipment it came off, so as long as the pump or the valve is named it does not matter which heading you arrived under. For a mixed box of small sealing and bearing items rather than one machine, seals, gaskets and bearings is closer.
Instrumentation and safety
Gas detection equipment, thermometers, transmitters, sensors, control components and evidence-led replacement requests. Certification is part of the item here rather than paperwork that follows it: a detector approved for a fixed installation is approved with the sensor it was type-tested with, and a request has to name the target gas and the measuring range alongside the instrument before a cell can be identified at all. This is the layer that measures and protects, so what brings a buyer here is usually a reading rather than a broken part: a channel that will not calibrate, a thermometer disagreeing with the one beside it, an alarm tripping on a plant that has not changed. Say which of those it is, and what the instrument is wired into: the same sensing element is sold in several housings. Sensors, gas detectors and thermometers carries the identity rules for the instrument, and where a class or flag requirement is attached, the supply documentation is worth settling inside the same enquiry.
Electrical and automation
Marine electrical, automation and navigation-related equipment references where a correct technical identity can be established. Two components with the same rating are routinely not interchangeable on this side of the vessel — a contactor differs by coil voltage, a voltage regulator by sensing mode, a breaker by the trip unit and the settings the switchboard was coordinated to — so an electrical line is answered from the nameplate and the installation together. The practical consequence is that a photograph of the device is rarely enough: the panel label, the circuit it feeds and the drawing position carry as much of the identity as the component body does, and on a breaker the trip unit is often a separate order line from the frame. Electrical and control components sets out what each group is identified by, and the marine electrical spare parts guide works the same ground system by system.
HVAC and environmental systems
Refrigeration, ventilation, BWTS and environmental-system requirements with maker and system context. These systems are usually assembled from several makers under one system name, so the component plate matters more than the package plate: the compressor, the controller, the valves and the treatment unit each carry their own identity, and a request written against the system rather than the component is the most common reason one of these lines needs a second round. The name on the enclosure belongs to whoever integrated the package, and the part you need was almost certainly built by somebody else; open the door and read the plate on the item. Refrigeration and air handling is covered in the HVAC and refrigeration sourcing guide, scrubber and ballast-treatment equipment in the exhaust-gas cleaning guide.
Deck, steering and service items
Deck, steering, mechanical and service-kit requirements supported by references, drawings or photos. Much of this equipment predates any electronic parts record on board, so a photographed drawing position, a page from the original manual or an old order line is often the strongest evidence available — and it is usually enough to begin. Outside the machinery space the plate is also the part most likely to be gone: painted over, corroded flat, or replaced during a conversion by a plate describing something else. Then the useful evidence is cumulative rather than singular — the removed component beside an object of known size, the casting marks, the drawing sheet number, the wording of the last purchase — and sending an RFQ without a part number sets out what that package looks like. The RFQ evidence checklist is the shorter version, to work through while the component is in front of you.
