Albert Barnes on Acts 27:41

And falling. Being carried by the wind and waves.

Into a place where two seas met. Gr., Into a place of a double sea. διθαλασσον. That is, a place which is washed on both sides by the sea. It refers properly to an isthmus, tongue of land, or a sand-bar, stretching out from the main land, and which was washed on both sides by the waves. It is evident that this was not properly an isthmus that was above the waves, but was probably a long sandbank that stretched far out into the sea, and which they did not perceive. In endeavouring to make the harbour, they ran on this bar or sand-bank.

They ran the ship aground. Not designedly, but in endeavouring to reach the harbour, Acts 27:39.

The hinder part was broken. The stern was broken or staved in. By this means the company was furnished with boards, etc., on which they were safely conveyed to the shore, Acts 27:44.