Did you know you can use textures to fill a polyon in QGIS? No? Well you do now!
The cool thing is you can get results like this with a simple SVG and a texture.
So how do you do it? Lets give it a go.
First grab a texture you want from http://texturelib.com/
Install Inkscape, or any other tool that can create svgs with textures.
Drag and drop your texture into Inkscape and embed the texture into the SVG:
Twaek any settings you need in Inkscape and save it somewhere QGIS can find.
Tip: You can configure extra search paths for svg in Options -> System -> SVG Paths
Open QGIS and load a polygon layer
Change the symbol type for the style to SVG fill and selet your SVG
Opps that’s not right
Enter the handy blend modes added by Nyall.
Change the blend mode to Soft Light and move the layer to the top of the drawing list
Now go and make some pirate maps.