Synonyms of navigational

2 Syllables
yachting, boating, seagoing, shorer, shipping
3 Syllables
littoral, nautical, seaside, marine, seafaring, thalassic, aquatic, oceangoing, oceanic, sea-loving, sailorly, ocean-going, saltwater, neptunian
4 Syllables
navigating, maritime, natatorial, hydrographic
5 Syllables
oceanographic