the officer second in command on a merchant vessel. In Navy, petty officer who is assistant to warranty officer, eriharidusega laevajuht, tsiviillaeva juhtkonna liige, kes vastutab laeva ohutu meresõidu eest ning seisab mere-ja sadamavahis

boatmaster - the person who has the necessary aptitude and qualifications to sail a vessel on the Member States' waterways and who has nautical responsibility on board