10 sec exposure for the sea and 4 mins exposure for the sky with B+W 110 ND filter, in both exposures I used cokin tobacco grad and blue grad filters (but in the end I decided to convert it to black and white!! ). Why did i take 2 exposures, why not just use the one with the ND filter?! simply to avoid noise, so that I can sharpen the rocks properly and get a clean image, usable for a large print. As for the sky, its not a big deal if you get some noise there, you can use lots of noise reduction without any worries, sometimes it even look better when its over softened.
This bright area in the sky on the right is the moon