Units of measure on ship stores lists: PCS, SET, LGH, CL and more

What does UOM mean on a ship stores list?

UOM means unit of measure: the unit in which one line of the list is counted and priced. "2 PCS" is two single pieces, "2 SET" is two complete sets and "2 CL" is two coils. The unit is part of the ordering specification, so a quantity written without it can be read in more than one way.

In IMPA-coded catalogues each code has its own unit, shown next to the description. Because the unit is attached to the code, the sensible habit is to write four things on every requisition line: IMPA code, description, unit and quantity. The IMPA Marine Stores Guide is built around the six-digit code, as explained in what an IMPA code is. The unit comes with that code, not from the seller's preference.

Which units appear most often?

Most lines are counted in pieces, with sets, lengths, sheets, coils, pairs and kilograms making up much of the rest. The table lists the abbreviations you will meet most often and what one ordered unit means.

Other units that appear in ship stores data include RLS (roll), SHT (sheet), CAN, BTL (bottle), TIN, DRM (drum), LTR (litre), TUB, CT (carton) and DOZ (dozen). Check the unit shown for each code, because the same product type can be counted differently in different sections.

Why do a coil, a length and a metre differ for rope and pipe?

They are three different ways to count the same material, and the quantity changes by a large factor between them. A coil is a full reel of rope or hose as supplied, a length is one standard length of pipe or bar, and a metre is a single metre cut from stock. The number on the list means nothing until you know which one it refers to.

• Rope. Mooring rope in the Guide is usually priced per coil, where a coil has a stated length (a catalogue description may read, for instance, "x 220 mtr"). Ordering "220" of a coil unit would mean 220 coils. If you want a particular number of metres, the unit must be MTR and the supplier must agree to cut it.
• Pipe and tube. These are normally counted per length, and a length is a fixed size from the mill or stockist, commonly several metres. Check the stated length before converting a metre requirement into a number of lengths.
• Cables and wire. These may be sold per metre or per drum or coil. Ask whether a cut length carries a different price or minimum.

Rope size also has two common conventions, diameter in millimetres and circumference in inches, which is a separate source of mix-ups. Write the unit of size next to the number.

What are the common abbreviation variants?

The same unit is often abbreviated in more than one way, and the variants are spelling differences, not different units. Common pairs are PR and PRS for pair, ROL and RLS for roll, PCE and PCS for piece, TN and TIN for tin, ST and SHT for sheet, and CA and CAN for can.

Where lists follow the UN/ECE Recommendation 20 trade code list, the codes look different again. That list uses MTR for metre, KGM for kilogram and LTR for litre, while many ship stores lists write KGS for kilograms. Treat KGS and KGM as the same thing in this context, but ask if a list gives KGS where the product is really sold by the piece, because a mass unit against a count unit is a real mismatch, not a spelling one. Bread listed per kilogram on one list and per piece on another is the standard example.

Be careful when a column is just called "Unit" or "Pack". It may be the selling pack rather than the IMPA unit.

How do you avoid ordering the wrong quantity?

Write the unit on every line, compare the unit on the quotation with your requisition, and state any pack or length you rely on in words. Most wrong deliveries come from a unit that was assumed, not from a wrong product.

1. Quote code, description, unit and quantity together, one item per line.
2. Spell out multi-piece units. For a SET or PKT, write the contents if they matter ("socket set, 1/2 in drive, 10 to 32 mm, 16 pieces" is clearer than "1 SET").
3. State rope and hose lengths. Write the coil length and the size convention, for example "mooring rope, 8 in circumference, 220 m coil".
4. Convert deliberately. If you need 600 m of rope and the unit is a 220 m coil, say whether you want three coils, whether the surplus is acceptable or whether you need cutting.
5. Re-read the quotation. Check that the unit price and the unit match the requisition before you accept.
6. Confirm any change. If a supplier replaces a coil with metres, or a box with single pieces, ask for a revised quotation rather than adjusting the numbers yourself.

What should you do when a unit is unclear?

Ask before you order. Send the supplier the code, the written description and what you actually need to receive, for example total metres, number of pairs or number of cans, and let them confirm the unit in writing. In an RFQ this costs a short message, and a wrong coil count costs far more.

You can search by product name in the ShipsBay catalogue to see how a given item is described, build your list in the RFQ cart, or send an existing list as a document. Whatever route you use, check the unit on each line of the quotation before accepting it.