Two-stroke outboard: what displacement triggers a nautical licence?

Within six miles and on inland waters, a licence is required if the engine exceeds 30 kW or its displacement threshold: over 750 cm³ for a carbureted 2-stroke and over 900 cm³ for direct injection.

Fuel system sets the displacement limit

Article 39(1)(b) distinguishes carbureted two-strokes from direct-injection two-strokes: displacement must exceed 750 cm³ for the former and 900 cm³ for the latter. Within six miles and on inland waters, a licence is required if displacement exceeds the applicable limit or power exceeds 30 kW (40.8 CV). Exceeding either threshold is sufficient.

“Above” means strictly greater: exactly 750 cm³ for a carbureted engine and exactly 900 cm³ for direct injection do not exceed their displacement limits. The power test is separate: power above 30 kW triggers the licence even below the displacement limit; displacement above its limit triggers it at or below 30 kW too. Check the fuel system in the engine papers. If the records are incomplete or conflict, ask the Port Authority to confirm the classification.

For example, a carbureted 800 cm³ 2-stroke at 28 kW requires a licence because it exceeds 750 cm³; a direct-injection 800 cm³ 2-stroke at 32 kW requires one because it exceeds 30 kW, even though it is below 900 cm³. An engine that exceeds neither its displacement limit nor 30 kW does not trigger this specific requirement. Beyond six miles, a licence is required regardless.

Read the engine plate and certificate

Find the engine model and serial number, then check displacement, maximum power in kW and fuel system separately. Compare each figure with its applicable threshold and check the planned navigation area: beyond six miles a licence is required regardless of the engine. If the unit has multiple motors or conflicting records, ask the Port Authority how to assess the installed configuration.

Quiz Patente Ufficiale helps with chapters, exam quizzes and error review on common rules. It does not interpret an outboard’s plate or issue a nautical licence; compare the engine documents with the MIT page.

Quiz Patente Ufficiale helps you review road theory with category B chapters, exam quizzes and mistake review.