Aviation, what is the equivalent word for ships instead of aircraft?
The design, development and production of nautical vessels: shipbuilding or boatbuilding (depending on the type of craft);
The operation and use of nautical vessels: navigation:
- The process or activity of accurately ascertaining one’s position and planning and following a route:
Columbus corrected his westward course by celestial navigation- The passage of ships:
transporter bridges to span rivers without hindering navigation[ODO]
You can consider seamanship which covers maritime navigation as well. Still does not cover ship building though.
It involves topics and development of specialised skills including: navigation and international maritime law; weather, meteorology and forecasting; watchstanding; ship-handling and small boat handling; operation of deck equipment, anchors and cables; ropework and line handling; communications; sailing; engines; execution of evolutions such as towing; cargo handling equipment, dangerous cargoes and cargo storage; dealing with emergencies; survival at sea and search and rescue; and fire fighting.
Marine, maritime, naval, nautical are used before nouns depending on the context also.
Note: There is the word airmanship similar to seamanship.