[2019] New ships

You can use free XP, but you have to go up the tier ladder of ships. in other words, you need to Unlock the Kawachi, before you can move on to the Myogi.
To get from the Knogo you have to unlock 2 different hulls for the Myogi before you can unlock the Kongo.

My advice would be to grind some of these ships before you spend a good chunk of XP, just so you can understand how they play and what they can and can not do.

Best of luck sir.