Imagine you've locked onto the closer one but are aiming at the further one. Imagine two ships, one 18 km from you, the other 20km, 2km behind it. This makes it much easier to aim, especially when you want to hit the superstructure or hit slightly below waterline - but it also means that if you have a target lock on the WRONG ship, your salvo will be f*cked up like hell. If you shoot, your shells will hit superstructure (the ones precise enough, at least - since there's the random factor involved) Aim at ship's superstructure? Now you're aiming at the superstructure - your gunners still assume that the DISTANCE you want to shoot is the same but you want your shells to reach that given distance at specific height over the water. with target lock: you aim at the selected ship. If you fire like this, you'll probably overshoot, possibly by a lot. Aim at ship's superstructure? Now you're aiming at the water you WOULD be pointing at if there was no ship there. without target lock: you aim at a place in the water. The aim assist that goes roughly like this (assume stationary target for cleaner example):

The shells don't land exactly on the pixel you picked - there is a bit of randomness involved and this randomness is bigger when firing without target lockĢ. So shells are not just going on the pixel you aim, there is something else behind. This happened by mistake at first, so I realized what's going on and from there on I always carefully select with X the correct target I intend to shoot. While when aiming at the correct target selected (with X) the shot goes spot on, with the guns being at the same position. When 2 targets are close enough and you aim at the de-selected one (not with X), the shot goes off.

Auto aim for world of warships