When the captain jumped on the ship, he covered his whole body and masked his presence with it. Thanks to his eyes it was flawless, for anyone else they would not notice him as the captain had successfully hidden with the ocean's presence.
He was controlling the water carrying to go down when his head turned in the direction of the tornado Mares and Felsen had fallen into. Others wouldn't be able to notice as the tornado made any energies on the surroundings too chaotic, but he could see the two entering it.
His eyes were terrifying, anything water-related had the potential to be under his control.
The only reason he couldn't use ice or vapor was because he lacked the skill to do so, and even still there was already a myriad of possibilities to be explored with what he could already do.