On 22 May 1941, Piorun, with ships of the British 4th Destroyer Flotilla (HMS Cossack, HMS Maori, HMS Sikh and HMS Zulu), commanded by Captain Philip Vian, provided additional escort to troop convoy WS8B en route from Glasgow to the Indian Ocean. On 25 May, Vian's destroyers (including Piorun) were detached from the convoy to join the search for the German battleship Bismarck.
Piorun took part, along with the British destroyers, in the search for the Bismarck (she was the first of the destroyers to spot the German ship). She joined in the shadowing of and torpedo attacks on the Bismarck during the night before Bismarck was sunk, and at one point Piorun charged at Bismarck by herself, exchanging fire for half an hour, although neither side scored any hits. According to one report (detailed at the Auschwitz I exhibition, Oświęcim, Poland), Pławski transmitted the message "I am a Pole" before commencing fire on the Bismarck. This manoeuvre and the subsequent withdrawal caused Piorun to lose contact with the Bismarck. Piorun was very low on fuel, so at 5 am, she was ordered home before she had used her torpedoes. Pławski was reluctant to leave the area and ignored Vian's order for an hour before returning to the UK.
http://en.wikipedia.org/wiki/ORP_Piorun_(G65)
26 May 1941
At 11.00 AM Capt. Vian (in HMS Cossack) recieved a radio report about the position of the Bismarck. He realized that the 4th Destroyer Flotilla was only 50 miles away and ordered to chase the enemy. Due to bad weather and high waves, the destroyers were able to maintain 27 knots speed (only two knots more than Bismarck), but continued the pursuit. Fortunately, British aircraft managed to hit the enemy with two torpedoes. One of them jammed the rudder and damaged the screws. The allied destroyers steamed in line formation, one about 25 cables from another. In darkness, Piorun lost contact with her British partners. At 2214hours lookouts spotted a large ship which indentified herself as HMS Sheffield. At 2237 lookouts detected another large ship. The Polish commanding officer Cdr. Plawski was afraid of attacking the unidentified vessel, because it could be HMS Sheffield again. Piorun used an Aldis lamp to transmit a signal. The answer was 6" gunfire, The detected ship was the Bismarck!!! Cdr. Plawski ordered to open fire with the six 4.7" guns. During 59 minutes Piorun continued transmitting radio reports and traded fire with German battleship achieving several hits. Of course, 4.7" shells were able only to destroy some light AA guns, but not to penetrate heavy armor. The Polish destroyer was making lot of evasive manouvers, because Bismarck also used her 15" main armament. The British destroyers appeared on scene and conducted a torpedo attack against the Geran battleship. But all torpedoes missed the target. At 2336hours Piorun lost contact with the enemy
http://www.uboat.net/allies/warships/ship/5423.html
Edited by Kangoroo - 30-Jun-2012 at 12:42