Laurence,
Welcome to the forum! Second Beach is a lovely location to shoot with a ton of options. With regard to your image, I like how you are playing with objects in the foreground leading to background items of interest. If you are ever back at Second Beach I'd suggest trying this reframed a couple of steps to the right, so the larger rocks on the left edge of the image aren't there. Then you can focus just on the foreground right rock leading out to the island in the distance.
Another thing to try (although it requires a stronger ND filter) is to run an even longer exposure, to see changes in the patterns of the wave. At 4-6 minutes you'll get very interesting effects around the rock that can be quite entertaining.
With regards to NationalTrussed's comments on cropping, it's a huge religious debate, but I have to disagree
If I only cropped to what the viewfinder sees, none of the images in my
Washington Coast gallery would be possible (they were all cropped, some extensively, after shooting).