Simply press the left or right arrow key on your keyboard to fix it once the camera angle gets locked.

Check down near where you're heading with Eagle Vision! You can still use it under water!

Waypoints are a big help, not only do they show you the direction, they mark it on your HUD so you can swim directly towards it! No more searching through multiple lairs of those unlucky ships!

Sometimes the best way to get by a shark is just to swim right past it! Even if it attacks you and you loose a little health, you gain your health back as soon as you make your way to a barrel and get one more taste of fresh air before returning to your hunt! So go out there take on those sharks like a real pirate!
(Warning, repeat action of "taking on the sharks like a real pirate" may result in the following symptoms:
Death.
Not living anymore.
Meeting up with your great great great grandparrents.
Insides of your body being outside.

Please act like real pirates smartly as I do not take any responsibility for you attacking it with half a health pip.)