I need help with maxing naval SL grinding so I can start making 300k-1.1m each round

i am disappointed that i only make 52k max with a 600% SL multiplier. I want to make more than that and make atleast 300k

my german ships have 600% SL multipler

Invest in Premium and you’d of made 84004 more! Next sale, break open the piggy bank and then you’ll really take advantage and make some SL!

I profit best with the US ships, especially the destroyers at 5.0-5.3, much more efficient than the Germans or any other tree, iirc.