Not seen this before - looks quite promising
https://store.steampowered.com/app/1503500/Uboat_Commander/
(https://www.grogheads.com/forums/proxy.php?request=http%3A%2F%2Fshutupandtakemymoney.com%2Fwp-content%2Fuploads%2F2018%2F06%2Fshut-up-logo-1000.png&hash=793f0bf7c4dcf89c58c1294a779f20522925ad14)
Looks like it's from the people who made Tank Mechanic Simulator. Pretty ambitious as they are also doing a destroyer game that comes out 3Q 21 and a Tank game next year.