John 6:22
“And the people that were there saw that there was none other boat there save the one into which the disciples had entered, and that Jesus went not into the boat, but His disciples.”
And why is John so exact? Why said he not that the multitudes having passed over on the next day departed? He desires to teach us something else, namely, that Jesus allowed the multitudes if not openly, at least in a secret manner, to suspect what had taken place. For, “They saw,” says he, “that there was none other boat there but one, and that Jesus went not into it with His disciples.”
Source: Homilies on the Gospel of John (New Advent)