By 04:00 on 23 May, Lütjens ordered "Prinz Eugen" and "Bismarck" to increase speed to to make the dash through the Denmark Strait. Upon entering the Strait, both ships activated their FuMO radar detection equipment sets. "Bismarck" led "Prinz Eugen" by about ; mist reduced visibility to . The Germans encountered some ice at around 10:00, which necessitated a reduction in speed to . Two hours later, the pair had reached a point north of Iceland. The ships were forced to zigzag to avoid ice floes. At 19:22, hydrophone and radar operators aboard the German warships detected the cruiser at a range of approximately . "Prinz Eugen"s radio-intercept team decrypted the radio signals being sent by "Suffolk" and learned that their location had indeed been reported.