Nvm the main question about Sea defense, I just misread the manual I think

Just wanting to verify something…

Sea fleets from different nations don’t defend together right?

Just asking because I’ve been reading a lot of allied strat and I see combining UK/US fleets often.

Now, I know that US fighters on UK carrier will defend the carrier if G attacks the AC.

But would a US battleship defend a UK battleship if G attacks the UK battleship?

No right?

Side question, BB=Battleship right? And… why 2 Bs? Just don’t want to use BS?