Inboard diesel engine: when is a nautical licence required within six miles?

Within six miles and on inland waters, a licence is required for an aspirated diesel above 2,000 cm³ or above 30 kW; for a turbocharged diesel, above 1,300 cm³ or above 30 kW. Exceeding either applicable threshold is enough.

Aspirated and turbocharged diesels have different limits

Article 39(1)(b) distinguishes naturally aspirated and turbocharged diesels. Within six miles and on inland waters, displacement must exceed 2,000 cm³ for an aspirated diesel or 1,300 cm³ for a turbocharged one; power above 30 kW (40.8 CV) is an independent trigger in either case. Exceeding the applicable displacement threshold or the power threshold is enough to require a licence.

Check the engine papers to establish whether it is turbocharged or naturally aspirated. Do not apply the 2,000 cm³ limit to every diesel: a turbocharged engine has a 1,300 cm³ threshold. The number must be strictly greater; exactly 2,000 or 1,300 cm³ does not exceed the relevant limit. If the paperwork does not identify the engine type, ask the Port Authority before navigating.

For example, a 2,100 cm³ naturally aspirated diesel at 28 kW requires a licence because it exceeds 2,000 cm³; a 1,000 cm³ turbo diesel at 32 kW requires one because it exceeds 30 kW, even below 1,300 cm³. An engine below both applicable thresholds does not trigger this specific rule. Beyond six miles, a licence is required regardless.

Read the engine’s official data

Identify the make, model and serial number. Check displacement, power and whether the engine is turbocharged separately in the boat certificate and manufacturer records; compare each figure with its own threshold. Also verify the distance from the coast and whether you are on inland waters. Resolve mismatches before departure.

Quiz Patente Ufficiale helps you review common rules through chapters, quizzes and error review. It does not cover nautical specifications or verify an installed engine; use the official documents and MIT guidance.

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