Complex sentence: While moving people between ships, the "F174" received a hit in the bow from the "Iohan": the problem was underestimated and operations continued, but part of the bow planking gave way and water begun to enter the ship.
Split into simpler sentences: While moving people between ships, "F174" was struck in the bow by the "Iohan". The damage was underestimated and the transfer continued, but part of the bow planking gave way and water began to enter the ship.