I generally don't harbor-raid, but the other day I went into a one (I can't remember the name at the moment
) and found a large stationary task force with the Yamoto. Bagged me the Yamoto, a carrier and a light cruiser
Don't know how realistic that is, might be Time tO get RSRD... It was quite a sight though, should have taken a screenie, Cruiser slipping beneath the waves, Yamoto on fire with Decks awash on the seafloor, and a carrier inverted with the hull above the water.
As for strategy, though, I usually get closeish at night/evening, submerge, and get in the port about 4:30 in the morning to make my attack, right at sunrise