DD ORP Kozak 1953

End of The World War (1.IX.1947) saw PLK Commonwealth severely weakened. While a simple survival of the Soviet invasion can be seen as a massive victory, just as well as the fact that threat of US nuclear bombs finally put an end to bloodshed and revived old concept of status quo peace, the war ravaged eastern half of the country, while communist sponsored rebels took control in Polish East Africa. On Madagascar rebels were contained, but civil war was to continue for many years to come.

Navy, formerly pride of the state, was in tatters. Many ships were lost, but most importantly, post war reconstruction of the country forced massive cuts to naval budget. Almost all capital ships were scrapped or mothballed. Number of smaller ships was also greatly reduced and all new constructions were put on hold or cancelled. It took almost two years for the first new ones to begin.

Finally, in 1949 a new class of destroyers was authorized. Ships were designed to be effective in “small war” that dominated during World War in Baltic. But they also needed to be fast enough to operate with fleet task forces at home and overseas, be able to engage land targets and hunt submarines. Drawing onto war experience, decision was made to equip those ships with strong AA battery, to help them survive in zones saturated with aircraft, like Baltic. As result of all those requirements, Kozak class ships were to be bigger than any other DD leader in PLKC Navy and by many seen as a small scout cruiser rather than typical DD.  

As result, twin 12cm turrets recently developed by Cegielski Engineering were picked as main armament. Extremely advanced at the date of design, they were automatically loaded, resulting in fire ratio around 40 shells per minute.

Those guns were supplemented by 3in AA guns MK33 obtained from USA and 6 newest Bofors 40mm L70 AA guns. Two triple 533mm torpedo launchers were mounted on the sides amidships. They were capable of launching various torpedoes, from well tested and reliable wz.38 and wz.43 to newest homing TNN-52A (surface targets) and TNP-51C (ASW). Usually the middle tube housed ASW torpedo.

Initially six were planned but as the fast paced progress in aviation (widespread use of jet engines) and missile technology quickly reduced importance of AA artillery, only first batch of three were finished. All of them received names of inhabitants of regions of the Commonweatlh beginning with letter K: Kozak  Kaszub and Kujawiak. Second batch, planned to be laid down in 1951 were initially delayed pending reassessment and later cancelled in favor of new design.

Despite that, the class was considered a success, one of the reasons being that massive, long range bombers were not what PLKC Navy feared most. Instead, a swarm of light planes attacking at low altitude was seen as a main threat, especially as Soviets shown that they are ready to sacrifice multiple pilots and planes to achieve a goal, bombing in large groups from various directions.

ORP Kozak was laid down in Royal Naval Yard in Riga in August 1949, launched in September 1950 and completed in May 1952, ORP Krakowiak was laid down in Gdańsk Naval Yard in December 1949, launched in November 1950 and completed in June 1952 finally ORP Kurlandczyk was laid down in Vickers-Ventspils in January 1950, launched in March 1951 and completed in December 1952.

Colour variant:

 Full springsharp report:

ORP Kozak, PLK Commonwealth destroyer laid down 1949

Displacement:
    2 939 t light; 3 081 t standard; 3 619 t normal; 4 050 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
    (443,49 ft / 432,50 ft) x 41,01 ft x (13,98 / 15,21 ft)
    (135,17 m / 131,83 m) x 12,50 m  x (4,26 / 4,64 m)

Armament:
      6 - 4,72" / 120 mm 50,0 cal guns - 55,82lbs / 25,32kg shells, 150 per gun
      Dual purpose guns in deck and hoist mounts, 1950 Model
      3 x Twin mounts on centreline ends, majority aft
        1 raised mount aft - superfiring
      6 - 3,00" / 76,2 mm 50,0 cal guns - 14,29lbs / 6,48kg shells, 450 per gun
      Auto rapid fire guns in deck and hoist mounts, 1950 Model
      2 x Twin mounts on centreline, forward evenly spread
        2 raised mounts
      1 x Twin mount on sides, aft deck centre
        1 raised mount
      6 - 1,57" / 40,0 mm 70,0 cal guns - 2,19lbs / 0,99kg shells, 1 500 per gun
      Anti-air guns in deck mounts, 1948 Model
      2 x Single mounts on sides, evenly spread
        2 raised mounts
      2 x Twin mounts on centreline, aft evenly spread
        2 raised mounts
      Weight of broadside 434 lbs / 197 kg
      6 - 21,0" / 533 mm, 21,50 ft / 6,55 m torpedoes - 1,512 t each, 9,070 t total
    In 2 sets of deck mounted side rotating tubes

Machinery:
    Oil fired boilers, steam turbines,
    Geared drive, 2 shafts, 69 233 shp / 51 648 Kw = 35,00 kts
    Range 4 500nm at 20,00 kts
    Bunker at max displacement = 969 tons

Complement:
    233 - 303

Cost:
    £2,934 million / $11,736 million

Distribution of weights at normal displacement:
    Armament: 129 tons, 3,6%
       - Guns: 120 tons, 3,3%
       - Torpedoes: 9 tons, 0,3%
    Machinery: 1 614 tons, 44,6%
    Hull, fittings & equipment: 980 tons, 27,1%
    Fuel, ammunition & stores: 680 tons, 18,8%
    Miscellaneous weights: 216 tons, 6,0%
       - Hull above water: 50 tons
       - On freeboard deck: 74 tons
       - Above deck: 92 tons

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      1 196 lbs / 542 Kg = 22,7 x 4,7 " / 120 mm shells or 0,5 torpedoes
    Stability (Unstable if below 1.00): 1,01
    Metacentric height 1,3 ft / 0,4 m
    Roll period: 14,9 seconds
    Steadiness    - As gun platform (Average = 50 %): 49 %
            - Recoil effect (Restricted arc if above 1.00): 0,41
    Seaboat quality  (Average = 1.00): 0,55

Hull form characteristics:
    Hull has rise forward of midbreak,
      a straight bulbous bow and small transom stern
    Block coefficient (normal/deep): 0,511 / 0,525
    Length to Beam Ratio: 10,55 : 1
    'Natural speed' for length: 22,25 kts
    Power going to wave formation at top speed: 67 %
    Trim (Max stability = 0, Max steadiness = 100): 89
    Bow angle (Positive = bow angles forward): 25,00 degrees
    Stern overhang: 1,50 ft / 0,46 m
    Freeboard (% = length of deck as a percentage of waterline length):
                Fore end,     Aft end
       - Forecastle:    12,00%,  20,34 ft / 6,20 m,  18,04 ft / 5,50 m
       - Forward deck:    24,00%,  18,04 ft / 5,50 m,  16,40 ft / 5,00 m
       - Aft deck:    49,00%,  10,66 ft / 3,25 m,  10,66 ft / 3,25 m
       - Quarter deck:    15,00%,  10,66 ft / 3,25 m,  10,66 ft / 3,25 m
       - Average freeboard:        13,23 ft / 4,03 m
    Ship tends to be wet forward

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 158,1%
        - Above water (accommodation/working, high = better): 123,3%
    Waterplane Area: 12 225 Square feet or 1 136 Square metres
    Displacement factor (Displacement / loading): 91%
    Structure weight / hull surface area: 54 lbs/sq ft or 266 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0,72
        - Longitudinal: 0,91
        - Overall: 0,73
    Hull space for machinery, storage, compartmentation is cramped
    Room for accommodation and workspaces is excellent
    Caution: Lacks seaworthiness - very limited seakeeping ability