For any of you engineers. I know on modern ships they never change the oil they just keep it clean with lube oil centrifuges and filters. With some ships having 30,000 gals or more of lube oil that makes perfect economic sense. How did they do it back in Titanic's time and how much oil was in the system on the Olympic class liners? I read that Titanic had filters. Were those good enough back then to keep the oil in spec or did they do oil changes on those ships. I looked around but didn't find the answers.