For the insanity of it, I'll take a whack at this. Imagine Robert Conroy's book 1901 (German invasion of US in 1901). The Germans send their entire fleet and sink the US fleet. The US is forced to make peace, give Germany free access to Central / South America, Guam, Philipines, Cuba, Puerto Rico are now German possessions. US fleet reduced to costal defense force by treaty. Germany wins WWI as US stays out. US remains isolationist and never constructs significant navy. Sure it's ASB but you asked for a way ...
Bull. After heavy re-search in just such a war (for my TL) my odds are on the American fleet, not the German fleet.
I'm not going to disagree with you because I agree that the US navy was probably better at that time ... but the OP asked for a way for the US to end up with a wimpy navy ... likely or not, my scenario would accomplish it.