with Germany you start out with 40 ipcs. Usually you spend all of that on stuff - armor and infantry mainly.
If you take over 2 ipcs worth of territory and had not lost any, then at the end of your turn, you collect 40 + 2 ipcs = 42 ipcs.
Now if you did not purchase anything at the beginning of your turn, then you collect 40 (your starting income that you already had at the beginning of your turn) + 42 (what you collect this turn) = 82 ipcs. So yes - you may puchase 3 battleships . . . for some reason . . . if you choose . . . .