its true what you say about fleets though.
in my games as the US (as germany i just spam uboats and cruizergs lol) i always try to go with the CTF, that is, 4-5 carries, same number of escort carriers (CVL for you guys who dont get it), 5 light cruisers, and the rest destroyers.
against japan's navy, i usually just get 1 stack of 18 ships to go kick off the japanese's fleet activity. they will gladly send 10 carriers accompanied by 20 various other ships and get ridiculously low attack stats like 2 or 3 percent defense or attack, while my ships enjoy 60ish percent. needless to say this causes incredible loss rates for the japs.
but definitely follow lascars advice. 6 to 9 ships with the appropiate number of escorts should do it.
if youre like me, try to make small fleets for specific purposes: 2 carriers, 2 escort carriers, 2 light cruisers, and 3 destroyers for destroying surface vessels. even if you encounter japanese superstacks you can damage a ton of them before you even take some damage.