Adam Clarke, on John 6:19

“When they had rowed therefore about five and twenty or thirty furlongs, they see Jesus walking upon the sea, and drawing nigh to the ship, and they were afraid.”

“Had rowed - Their vessel was a small one only, something of the boat kind: as to sails, if they had any, they could not now venture to carry them, because of the storm. Five and twenty or thirty furlongs - Between three and four miles. The sea of Tiberias, on which they now were, was, according to Josephus, War, book iii. chap. 25, forty furlongs, or five miles in breadth; and one hundred and forty furlongs, or eighteen miles, in length. Pliny, lib. v. chap. 15, makes it about six miles broad, and sixteen long. They see Jesus - See the notes on Mat 14:25, etc.”

Imported from an open dataset — not yet checked against the printed edition.