Same here I just recently started playing SH5, but since I've played SH3 many many years I felt confident enough to start with real navigation play style.
What comes to my mind is that the contact might have changed it's course and thus not be where you expected it to be. Or maybe the contact info was inaccurate (speed and heading). Not really sure how the mechanics in the game work regarding contact reports.
As a basic advice for new players I would recommend you watch Stoianm's video tutorials. He's made tutorials almost about every aspect of the game.
He's helped me to get back on track with this newest game on the series.
As of now I'm trying to learn the four bearings method hydrophone hunting.
As this is the most supportive and friendly forum in the www, I'm sure more experienced skippers will come to your assistance very soon.
