Hi.
I suggest you first rise to periscope depth , and take a look around , ( you can press P while you look to see which direction that oiler is .
You will probably then notice that it has appeared by then , on your B tac as one of the red dots .
There's a few ways to play this mission.
The objective is the oiler .
One way , is just head towards it , and fire spreads , there are plenty torpedoes in this mission ! The two corvettes will not interfere much . If they happen to do so , after a while , fire one in the general direction of the nearest , and it will turn away . Eventually , if you haven't sunk that oiler , they will get more determined ,, and are armed with hedgehogs .
Another way , is to destroy those corvettes first . Start heading towards oiler ,as above , so you will be nearer to it ,until the first corvette is about 1000m .
Sinking the corvettes on this mission will require pivotting and general tactics ..using both bow and stern tubes etc.
There is a time limit on this mission ..That is why it is good to head towards the oiler . If you take too long , and , are too far away , it escapes .
What ,more specifically , are you finding difficult ?
Most things are on the forum postings , if you look thru the months of them .
SOMEONE might add a " Look Here " ( with underlining -as a link to something) !
Try the other factions ' missions , and return to the USN . ; or try a surface mission . Often , taking a rest , and playing a different mission helps.
Oh.. the sonar thing,, Well those dots ..which look like radar , You will find postings about those . You might even have completed the mission already !
You will.