My first question is why does the sea have an entity order of 1000? That sounds like your issue, fix that and the rest will fall into place.
I'm guessing you're getting z buffer issues and probably using a single plane for your sea, and that plane is probably always at the original point you placed it.
So, here's some ideas you might want to try out..
If you are using a plane, try moving it so that it's always directly under the camera, this should reduce the zbuffer problems you probably encountered as you move further away from the original point.
Reduce the amount of z-buffer you have in your scenes by reducing the camera range.
I'm guessing you're getting z buffer issues and probably using a single plane for your sea, and that plane is probably always at the original point you placed it.
So, here's some ideas you might want to try out..
If you are using a plane, try moving it so that it's always directly under the camera, this should reduce the zbuffer problems you probably encountered as you move further away from the original point.
Reduce the amount of z-buffer you have in your scenes by reducing the camera range.