The officers were less optimistic.

They had never seen one raise itself up vertically, tilting its stern high in the air before sinking.

Perhaps it simply had been damaged and obliged to hide.
The loss of the submarine was a sure thing in Caragol's estimation, and he considered it entirely unnecessary to ask the name of the one who had blown it to smithereens.
"It must have been that lad from Vannes....

He's the only one who could have done it." For him the other gunners simply did not exist.

And, inflamed by his enthusiasm, he wriggled out of the hands of the two seamen who had begun to bandage his head with a deftness learned in land combats.
Ferragut was entirely satisfied with this encounter.