Adam Clarke on Matthew 13:2

Into a ship - Το πλοιον, The vessel or boat. Mr. Wakefield supposes (which is very likely) that a particular vessel is uniformly specified, which seems to have been kept on the lake for the use of Christ and his apostles: it probably belonged to some of the fishermen, (see Mat 4:22), who, he thinks, occasionally, at least, followed their former occupation. See Joh 21:3.

The thought of pious Quesnel on this verse should not be neglected. We see here a representation of the Church, which consists of the people united to their pastors. These, being more exposed to violent tossings and storms, are, as it were, in a ship, while those continue at ease on the shore.