When they go under water the appentage retracts, with it turning to the side, the "arms and head" pulling in, while the "torso" pulls down to the level of the dorsal fin, to form a rough 2nd dorsal fin, it certainly is cumbersome, and these sharks are some of the worst at swimming ever found, however they don't need to be as good as swimmers, as their prey comes to them.
Read next
From @dkmilon