Just by way of explaining what is required, this photograph from Fergal is fine and looks good at screen and full size http://www.shipspotting.com/gallery/photo.php?lid=1673207#
and is natural in appearance and is what we are looking for, this one is overexposed http://www.shipspotting.com/gallery/photo.php?lid=1643211
producing a halo effect.
However this one is reasonable at screen size but falls away at full size http://www.shipspotting.com/gallery/photo.php?lid=1798810
and has an unnatural appearance as a result of over enhancing which can be clearly seen and is unacceptable.
Tuomas's photographs are also fine and natural looking.
There is also a problem with some HDR (High Dynamic Range) uploads, they can produce an unnatural sea and sky and come under the heading of being Artistic, with care these HDR images can give good results and that is really what it is all about.
As I have said enhanced photographs are permissible providing that they are not overdone with the red boot topping and other bright colours hitting you in the eye, it should be done in moderation and the aim should always be for a natural looking photograph.
I do not propose to give any further examples and I hope that no more are included in this thread, I think the examples I have given are enough in explaining what is expected and the aim is for natural looking ship photographs and not Artistic ones, as I have said there are other outlets for them so take care with your enhancing by making sure that the quality is good at screen and full size and also natural in appearance and you will have no problems.