Gollevainen - Oh, wow! Thank You very much!
Hood - Thank You for such a high score.
As for the bilge keels, I admit it - my error. Now I've added them. As an explanation I can only say, that sources available to me differed about it - some didn't mention them at all, some said that one version had them, one hadn't, some that both versions had them, and some didn't mention it at all as they were showing the ships only above the waterline.
As for the waterline, I was convinced it WAS black. I don't know how could it happen.
I hope that now it's really the final version.
And here is the drawing of Groźny's older sibling - coast guard patrol craft of the 912 type (Fala class, or Obluze in NATO code). In the years 1965-2008 five such vessels served in the Maritime Brigade of the Border Defence Troops, renamed in 1991 into Border Guard. Picture shows one of the ships (actually ORP Zefir) during last years of it's service (ca. 2004).
It should be noted, that during their service their tactical numbers slightly changed. Initially first three units wore numbers (respectively): OP-301, OP-302 and OP-303, but in 1967 numeration was changed and they were renumbered to OP-321, OP-322, OP-323 and two newly-built units in the series were given numbers OP-324 and OP-325. After formation of Border Guard ship numbers were changed into SG-321, SG-322, SG-323, SG-324, SG-325. (OP means Okręt Pogranicza - Border Ship, SG means Straż Graniczna - Border Guard)