Unknown Movie (Please Identify for me)

[alanf0]

A couple of years ago, i have watched this movie on Sci-Fi channel, I though it was good but i forgot the movie name:confused 1:
The story looks sort of like the Odyssey.
I remember this part where an old guy and his crew went inside a cave on a boat (its like a underground water source ), and some sort of hydra mysterously eats his men. When they reached the outside of the cave. The water opened up and a whirlpool was created by a big mouth of a monster.
He went back to the kingdom and was some sort of king that got lost which people thought he was dead or sumthing. He used arrows to shoot the beggers at his house to regain his royalty

Thats all I can tell you. please tell me wat the movie was cuz this is really bugging me
Thanks, Alan