Advice on what to purchase?

Is the starter box like many starter boxes in that it only gets me to 75% of what I need for most scenarios? I am curious if I need additional sets to allow me to play 90% of the scenarios in the rule book. So if I wish to have a good compliment of German and Royal fleets should I get the Starter plus the fleet kits for both navy’s or is that too much? Maybe fleet boxes and rule book instead? Or starter plus a couple of individual models? It looks like I could use the tanker either way. Thanks for the help!