It does not tell you if the target is closing or moving away. Often time it's fairly important information. you know know where the DD is NOT as much as where he is, and you know that dd is less the 11 Km away from you or your RPF would be pointing at the BB's! If you cant see it, it's that one DD because you can see the 11 BB's! Yep totally over the top example, but it's there simply to illistrate. But, your RPF contact is off your left side.

SO your moving along and the BB's are out to your right at 11 Km out to 18 km. you can spot them from orbit!) and one lone DD. Say your facing a team of 11 battleships. How much it can tell you is entirely dependent on your knowledge of the game, it's maps, it's ship, and how players move. It's not much by it's self other then a tool that gives you information. It gives you an approximate heading to the nearest opposing ship. I'm reasonably expert with it at this point though somewhat far from a 'God of RPF' as of yet! It's OP, it's useless,and everything in between.

You've heard both about Radio Position Finding or RPF. It's a tools of the trade briefing today and the topic is RPF.

World of warships rpf on missouri