Jamieson, Fausset and Brown on Acts 27:30

30. as the shipmen were about to flee out of the ship--under cover of night.

when they had let down the boat ... as though they would ... cast anchors out of the foreship--"bow"--rather, "carry out" anchors, to hold the ship fore as well as aft. "This could have been of no advantage in the circumstances, and as the pretext could not deceive a seaman, we must infer that the officers of the ship were parties to the unworthy attempt, which was perhaps detected by the nautical skill of St. Luke, and communicated by him to St. Paul" [Smith].