Ordinary seaman

From WikiPOBia

The Ordinary seaman was the lowest rating for a capable sailor. Also called simply an "Ordinary", he was a step up from the complete novice, the "landsman", and could be expected to know his station and task, i.e., where he was supposed to be at a given command and what he should do. As an ordinary seaman became more experienced and learned more skills he could be rated as an "Able-bodied seaman".

The term survives in the US Merchant fleet as the lowest level of Merchant Mariner Documentation (MMD).