CPV code 35521100 designates Engines and engine parts for warships in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
35521100 is a leaf code — the most specific level of its branch — so it can be used directly as the main CPV code of a contract notice. If it does not quite fit, check the neighbouring codes under 35521000 (Hull and mechanical spare parts for warships).