Yes, you are correct; men in the lifeboats were on their own. The ship’s captains had orders to keep going.
I once knew a real estate developer whose formative experience in life was a day and night spent on a lifeboat adrift above the Arctic Circle after his merchant ship was torpedoed on the Murmansk run in WW II. An unexpected rescue by the Royal Navy saved his life and gave him the chance to get a college education and the determination to pursue a business career that made him wealthy building subdivisions and towns on Long Island. A working retirement from New York to South Florida fulfilled his dream of never again having to experience cold weather.