I agree it looks a little bit fake, mostly due to the colour. Also because of the rays of light comming down from the sky, which may or may not be fake, but because the colour is a bit off they give that impression.
More important to me however, are the blown out highlights on the water. You're losing a lot of detail there, and it makes it look too sharp/pixelated. You shot it at f5.6 1/1000 iso 160 - if you'd stopped down a little so that you kept that highlight detail, and then raised the shadows in post, you'd have much more control.
You can raise the level of shadows far far easier than lowering highlights. Once those highlights go to white, that's it! They're gone.
Nice capture though, and I too would love to see an unprocessed version.
EDIT:
My quick take on it. Converted to black and white, little bit of a blue tint (blue is calming which I thought fit quite well, could have used orange/red to get a warmer feeling), and played around with tone curves/exposure etc in lightroom to get a bit more contrast in the clouds, and really bring those light rays out. Also put a grad filter on the top half of the image to under expose the sky a little. Used a filter on the water and adjusted clarity so it would blur the highlights a little, and then roughly masked out the boat and bumped the exposure on it just a touch. Finished off with a vingette to draw the viewers eye more towards the boat.
Not saying thats how it should be done, definetley not, but just some ideas to get you going. With a high res version of this you could do
so much great stuff with it! Even more so if you shot it in RAW.