Below is a watercolor I did a few months ago.While I was painting it, I thought it would be interesting to take in-progress shots for fun. So I will put the photos from start to finish (without the first pencil sketch.)
First couple of washes. Light background, darker tones, green on seaweed.
More color. Seaweed.
I felt that the extra seaweed was too much so I added more ultramarine to cover them and add more depth to the water.