sentences:  In an unusually long engagement for a submarine, and in a situation for which neither crew had been trained, Launders waited 45 minutes after first contact before going to action stations.Launders was waiting for "U-864" to surface and thus present an easier target.Upon realising they were being followed by the British submarine and that their escort had still not arrived, "U-864" zig-zagged underwater in attempted evasive manoeuvres, with each submarine occasionally risking raising her periscope.