I wanted the Ottoman Nefs to appear completely different in style to the Knights of St John, more 'Dig like', more 'old fashioned' and with modelled features that would make them instantly recognisable. The answer was bullet-like bodies, big tails and large, flat turrets.
These three photos give an idea of what I was looking for. The style and colour scheme is very different from the Holy League ships - plainer, with less gun turrets and a simpler structure.
The colour scheme is much less bright, but the dark grey 'Mickey Mouse' camouflage around the superstructure adds some variety (I may keep this idea for future Nefs) while the Green Ottoman Naval Ensign was culled from the Internet and hand painted.