Yellow triangle?

[The scorpion]

It could be a strange title but what I mean is when you select a target ship a yellow or in some cases red shows, you can then fire torpedoes and often get a hit. I just cant get used to manual targeting, and not through lack of trying.
I know it sounds a bit like cheating but I was used to doing it that way a few years ago.
I was using TWoS mod at that time as I am now.
So my question is is there a way to get my lock triangle back.

Any help gratefully received