Actually, that message is rather important.
How would you feel if you put 2-3 torps into a tanker and sailed away thinking that the ship was sinking only to find that you weren't credited for it.
You need to receive this message to know 100% that you will get credit for it.
If you still want to get rid of this message then you can comment it out of the correct cfg file. Someone will have to let you know which cfg it is as I'm currently experiencing a brain block.
