Thanks for the replies, everyone!
The title is for the rock on the left of the image standing strong against the current. I thought about naming it "Z", for the shape in the waves I see, but I try not to be too literal in my image naming.
I had to experiment with several exposures before finding the one that gave me the best water motion. I started with 2 seconds, but that blurred the water too much and reduced contrast in the waves. For this scene, 1/2 second was perfect.
This is a composite image of 4 verticals. I've discovered that it's HARD to get a good merge of a subject like this and had to go into Photoshop and work to remove a lot of disjointed seams. The combination of images may also be contributing to the look of the whitecaps.