The Dutch shipbuilding and marine equipment industries are part of a maritime cluster of about 17 200 Dutch maritime companies that also includes ports, the offshore industry, shipping, dredging, maritime services, fishing, inland shipping, naval activities and the watersports industry. In 2017, the maritime cluster accounted for 3.1% of gross domestic product (GDP) of the Netherlands. In the 1980s, the Dutch shipbuilding industry started to focus on high-tech, specialised vessels. Dutch shipyards produce a variety of vessel types, including dry cargos, dredgers, offshore service vessels, tugs, work/repair vessels, tankers, gas carriers, superyachts, cruise ships, passenger ferries, fully cellular containers, bulk carriers and roll-on/roll-off vessels. The Dutch Maritime Strategy 2015-2025 lists policy priorities and actions to promote the maritime and logistics sectors. The strategy takes into account global economic, demographic, geopolitical, ecological and security policy trends affecting the Dutch maritime sector.