“A great windstorm
The waves beat
Into the boat.
καὶ γίνεται λαῖλαψ μεγάλη ἀνέμου, καὶ τὰ κύματα ἐπέβαλλεν εἰς τὸ πλοῖον, ὥστε ἤδη γεμίζεσθαι τὸ πλοῖον.
This stormy boat ride episode can be found in Matthew, chapter 8:24, and Luke, chapter 8:23, somewhat the same as here. Mark said that a great severe windstorm came upon them (καὶ γίνεται λαῖλαψ μεγάλη ἀνέμου). There was no mention of an earthquake while they were at sea, as in Matthew. The waves of the sea were beating into the boat (καὶ τὰ κύματα ἐπέβαλλεν εἰς τὸ πλοῖον). Thus, the water was already filling up the boat (ὥστε ἤδη γεμίζεσθαι τὸ πλοῖον). They were in real danger.