Subordinate Ochre is a lower-ranked member of the Melnorme Trader vessel, Inevitably Successful in All Circumstances. He seems to be on friendly terms with Trade Master Greenish, as evidenced by Greenish's anecdote that he has predicted The Captain would visit them shortly, by saying "Fe-Fi-Fo-Fum! I smell the feet of a Hu-Hu-Man!", which was of great amusement to both of them. Perhaps coincidentally, The Captain indeed arrives later on that day. Ochre's exact job other than a subordinate to Greenish is not known.
Given the reference that Greenish made in his rhyme to the fairy tale Jack and the Beanstalk, the similarity between Ochre and ogre can hardly be a coincidence.