me and my dad have been stuck on that part and it's driving us insane. we know that your supposed to throw the spear things at it but it takes forever. is there any other way??
You are supposed to use the spears. It usually takes 12 or 13 to kill it. Stock up on herbs because it is a tough battle. Anytime it drags you start tossing spears. Once it dives under the water move all the way to the left of the screen when it pops back up start throwing more spears. Also make sure you are clear of the debris in the water before you start throwing otherwise you'll fall off.
It actually doesn't take long, but heres a faster way, hit it from far as you said, and when it tries to bite you or get close to you throw the spear down its throat, do it 2-4 times and its dead