General construction services of harbours and similar waterworks

**Includes:** - construction, repair, alteration and restoration services for: • harbour bottoms and harbour channels, breakwaters, quays, piers, jetties, docks, wharves and similar structures • riverworks and canal construction for water transport traffic • locks, floodgates, sluices, lifts, dry docks, slipways, barrages and other hydromechanical structures - dredging services, rock and silt removal and other water-associated construction services - underwater work (by divers, frogmen or other techniques) and various hydraulic engineering services

**Excludes:** - laying of submarine cables, cf. 54242 - pile driving services, cf. 54511