Imagine sleeping on a ship knowing that UBoats are sinking ships all around? Make for some insomnia?
My uncle did not like to talk about it, but he saw ships torpedoed, men on fire, and lifeboats full of men who could not be rescued. There were strict orders not to stop and take on survivors because to do so disrupted the convoy and invited further attack. The US Merchant Marine had an astonishingly high casualty rate in WW II. Promises of veterans benefits that were pledged during the war to keep the ships manned were never fulfilled.