U-Boats would be a waste of time - the CVs and carrier groups move faster than the top speed of any U-Boat. Your only hope would be to spend a couple of days cruising over to somebody's port in hopes of being able to shower them with torps when the CV respawned.
Until the Destroyers have depth charges (as well as the B-24s), and the Torps being slower than the CV gets fixed (seems that way to an old torpedo plane flier anyway), I don't think this will be on the "fast track".
EagleDNY