Shipping 161 History 116 Ships 101 Commerce 30 Merchant marine 24 Hydrodynamics 20 Merchant ships 20 Sailing ships 20 Coastwise shipping 19 Shipbuilding 19 Congresses 18 Transportation 17 Discovery and exploration 16 Biography 15 Description and travel 15 Harbors 15 Voyages and travels 15 Economic aspects 14 Shipwrecks 13 Navigation 12 Ship resistance 12 Naval architecture 9 Safety measures 9 Ship propulsion 9 Voyages around the world 9 Freight and freightage 8 History, Naval 8 Safety regulations 8 Ship models 8 World War, 1914-1918 8