Most delays in spares supply happen before anyone starts sourcing. Five fields usually decide it.

A spares enquiry either arrives with enough information to be priced immediately, or it starts a round of questions back to the vessel. The difference is often a day or more, and it is decided entirely by what was in the original message.

Five fields do most of the work: the maker, the equipment model or type, the serial or rating-plate number, the part number, and the position number from the maker's drawing.

The last one is the field most often left out and the one that resolves the most ambiguity. Makers reuse part numbers across model generations and across variants of the same machine. A part number on its own frequently maps to more than one article. The drawing position, read together with the model and serial number, narrows it to exactly one.

Where the rating plate is corroded or painted over — which is common on older auxiliaries — a photograph of the plate is more useful than someone's best reading of it. The same goes for the part itself: a photograph in situ, with something for scale, resolves questions that a description will not.

It is also worth stating the required delivery date and the port, in the original enquiry rather than after the quote. A part that is available in one location and long-lead in another gets sourced differently depending on where the vessel will be, and knowing that up front avoids quoting the wrong option.