Is the 'report contact' button of any use at all?

[Paul Riley]

After just hitting a medium cargo clean under the keel and right beneath the stack with a magnetic tip it still wasnt enough to sink it,in fact it doesnt even appear to have slowed at all!. I was seriously gutted,as that was my last torpedo of the patrol having sank two and could have really done with a third,hence my reason for risking a magnetic tip on this ship over the preferred impact tip.
After about an hour I decided to put some distance between us and shadow the target for a good 6 hours,or until nightfall,radioing base every hour on the target's position.I have now broke off as the target clearly has not been affected in any way.
My question is,is the report contact button of any use at all?.I am guessing (and hoping) this would give the Luftwaffe coordinates in order to bomb and finish any damaged ships off.Admittedly I attacked the ship in AN16 which is a LONG way from Germany,and I cant imagine they would get there in time before the ship found its way to its home port.

NOTE - Ever since I bought the game back in 2005 I have not seen the Luftwaffe once,except for one or two patrol planes flying overhead when leaving base.They are probably all getting pissed onboard Goerring's private yacht while we endlessly struggle out there on our own!

Thanks.