I must agree with Krutan... strange transparency.
Thought about it in previous boat video too, but with this big ship it looks even more odd. (try find a corresponding real picture
). The missing ship reflection is part of it anyway (and also perhaps missing/impossible to do smaller waves/ripples?).
While on-topic I realise there's also different light and clarity for different areas. I mean there is..
Glacial crystal clear water.
Mediterranean light water (equatorial high sun angle).
North sea ocean.
Mud water with 0 cm visibility.