What program are you making this in? Try and smooth out the lines a bit. Why is it called posiedon's revenge? What is he getting revenge on? How is he exacting that revenge?
pop the entire thing in illustrator, just the black and white drawing, live trace it and then smooth out your lines. it will look much cleaner. once you're done with that you can reapply the color using live paint, super easy.
I'm not sure I like the shape of the waves. I know they're stylized, but they don't look like water or hair. The static, plain blue contributes to that too.
i like the concept, yet it appears that the boat is floating, unless u want that effect, looks pretty cool. as for the trident boltds i feel that they are too symmetrical. try adding 1 or 3 more. or find a way to unbalance the symmetry.
i would say one or two trident/bolts, but its a bit busy. i think shading/color differention on posedon would help, and detail in the boat? or color? it might be too momcromatic for me, but i like its potential.