Vian's destroyer box around Bismarck

In this account, Philip Vian assigned a Tribal to each corner of a loose box so the flotilla could shadow Bismarck and keep attacking through the night. Piorun had exercised less with the Tribals and was recalled as having joined only one night exercise with them. She had more room to manoeuvre outside the box. A corner station demanded precise night navigation, since a positioning error could bring a destroyer too close to Bismarck or into collision with another ship. The reserve station remained in range and could reinforce any corner the battleship pressed. Holding contact bought time for King George V and Rodney to come up in the morning.