Welcome aboard, shipmate.
Supposedly, MP is coming. Personally, I don't think it will come any time soon. I predict not within the first year. If you desperately want a naval MP battle, you'll have to go with Harpoon, Naval War: Arctic Circle, or Fleet Command.
The least expensive and most supportable is Fleet Command. It's available via Steam as the
Naval Warfare Pack. It's also available via Amazon and some others. I would recommend
NWP Mod for it. It makes it an entirely different game, though it does struggle with newer OS and graphics cards.
NWAC is no longer supported by it's developer. It's available via Steam as well. It's a more futuristic game and has limited database and playability. It does work well with newer OS and graphics cards.
Lastly, there's
Harpoon Ultimate Edition. While I'm certain Herman and Gunny can tell you of it's strengths, I couldn't get past the dated engine (as a former owner of Harpoon II and it's subsets) and the frequent CTD I received, probably due to graphics card and direct x issues.
Ultimately, I would like a combination of NWAC/FC graphics of the various equipment and world, in a swappable window with the CIC appearance of Harpoon/CMANO, but that's my perfect vision. I would take some time to get to know the inner workings of CMANO so if and when MP/PBEM/CO-OP does arrive, you're already a hardened veteran and know the tactics and weapons available in the continued growing DB. Just my opinion.