Verm, that should be fixed now in version 1.052.
I tried shelling ships Tuesday in 1.050 and couldn't sink one.
Now in 1.052, 1 or 2 salvos from a single turret will sink a destroyer, 4 sank a cruiser, and 6 sank a carrier. HE rounds.
As for inacurate to real life fire control, well...yes. But I think HiTech and Pyro are not going to change it. They want to keep this mainly a flight sim still.
Besides, in such a miniturised and condensed warzone, having very short ranged guns is almost mandatory. You could shoot too much stuff otherwise, and not even bother leaving the dock.
Hans.