Ok, so I asked for advice on how to improve the image.
I've actually used the same kind of animation for both sails, but in different instances of animation.
For example, in the front-facing set, the animations are:
Frame 1, Front Sail: Animation 1
Frame 1, Back Sail: Animation 2
Frame 2, Front Sail: Animation 2
Frame 2, Back Sail: Animation 3
Frame 3, Front Sail: Animation 3
Frame 3, Back Sail: Animation 1
Then, instead of a horizontal gradient, the way I used in the Double Outrigger Canoe, I used a vertical gradient instead.
I was also able to put a little detail on the edge of the sails.
Full Spriteset Coming Soon.