How many spares you must carry: class and flag minimum stock

How many spare parts a ship must carry aboard is a question that draws too many confident, contradictory answers. Some of the requirement is hard, some is only the expectation of a charterer or insurer, and the rest is common sense dressed up as tradition. Separating those three layers lets you carry what you need, not half a warehouse just in case. Here is how to sort it out.

What is genuinely required

Historically, minimum spare parts lists for propulsion machinery came from SOLAS and the detailed lists of the classification societies. Today the picture is more layered: several societies have moved their own lists from required to recommended, so the hard obligation depends on the flag, the class and the notations assigned. An unattended-machinery or single-propulsion notation usually raises the required stock, because there is less redundancy. Rather than assume, check what binds your specific ship - it is one line in the class rules, not a general principle.

What is expected, though not mandatory

Even where class has relaxed the requirement, the expectation remains. Port state control, the ISM audit, vetting and the insurer all look at whether the ship can clear a typical failure itself without waiting on a delivery. The absence of a part that everyone carries is a remark in the report and an argument at a claim, even if it was not formally required. This layer is soft but real - and it usually decides the sensible minimum above the letter of the rule.

Arrange stock by criticality

• Critical: parts whose failure stops propulsion, steering or safety, and whose delivery takes time. Here the stock is beyond debate, regardless of the letter of the rule.
• Important: items that stretch a breakdown into days if missing - worth holding, with the quantity matched to delivery time in your trading area.
• Ordinary: widely available, short lead time - no sense freezing the store in them; sound reordering is enough.

Stock is a system, not a pile

Merely having the part is not enough - it has to be findable, current and serviceable. Minimum and maximum levels, a criticality ranking, used items reordered the moment they come out rather than at the next refit, and a check on shelf-life dates where they apply (rubber, electronics, elastomers). Dead stock of superseded numbers and expired seals looks fine on the inventory and is worthless in a breakdown. The spare parts list is a living document, not a once-a-year stocktake.

How this works with us

We will not replace your class rule, but we help turn the list of required and critical parts into a real stock: selection by type and serial number, quantity matched to delivery time in your area, certificates where they are needed, and sound reordering of used items. Send the list - we quote all of it, with OEM and approved-replacement lead times side by side.