While thinking of what to do next with the Pola, I noticed a black line!
To start, the prepeller shafts were painted anti-fowling green.
Looking at the paint scheme with the kit I noticed that there's a black lione which I think is called the boot top.
I ran two lines of 2mm masking tape round the hull to mark the boot top. Wider tape was them added to mask the already painted areas.
I remembered that I have some reference books, the Kagero plans for the Pola and the Ship Profile on the Zara class. The Kagero book doesn't show a boot top, but this is a book of 3D drawings. The Ship Profile has loads of black and white photos. It's not easy to tell, but the line below the light grey looks black, so the boat will get a boot top.
I sprayed the boot top with Lifecolor black and removed the wide masking tape.
With the rest of the masking tape removed, it looks likes it's an even line and in about the right place.
The light grey needs a little touching up. After than I think the hull needs a coat of varnish to protect the paint from scuffing.