Complex sentence: At 1255 hours, the ships received the signal via signal flags or radio from the signal tower at Oksywie, the respective captains of the ships opened the envelopes, and departed at 1415 under the command of Komandor porucznik Roman Stankiewicz.
Split into simpler sentences: At 1255 hours, the ships received the signal via signal flags or radio from the signal tower at Oksywie. The respective captains of the ships opened the envelopes and departed at 1415 under the command of Komandor porucznik Roman Stankiewicz.