And he spake to his disciples, that a small ship ( πλοιάριον)—literally, a little boat—should wait on him προσκαρτερῆ αὐτῷ)—literally, should be in close attendance upon him—because of the multitude, lest they should throng him.
This shows in a very graphic manner how assiduously and closely the crowd pressed upon him, so that he was obliged to have a little boat always in readiness, in which he might take refuge when the pressure became too great, and so address them with greater freedom from the boat.
St. Luke (Luke 5:3) says, "He sat down, and taught the people out of the ship," making the boat, so to speak, his pulpit.