Hello

I need help with some way to make rocky waters along a coastline to represent shallow deadly seas which is too shallow for ships to navigate.

I use Photoshop - but im no expert and have no idea how i could make it look good, the view is 2D top down (birds eye view). I have attatched a snippet of the corner of my map to show the current coast line,
I want to fill the blue ocean area with a rocky appearance without vegetation.

Click image for larger version. 

Name:	Capture.JPG 
Views:	42 
Size:	17.1 KB 
ID:	60264.

Any suggestions on how I could make something look good that matches the style in Photoshop?