Please remind me...
 

Sorry to post here but I can't find the calculation I'm looking for in the guides.

I tracked a ship for 3.3NM over 15min... how do I get the speed in knots again. My calculations used to involve the number 50 (if I remember right).

knots is miles per hour. so, in your case you multiply 3.3 with 4 (15 minutes is a quarter of an hour).

It usually senses me if I tag along for so long. So I use the Estimate speed feature.

Thank you sir. :)

I found the one I used to use, it was in a video tutorial...

3.3(NM) / 15(min) x 60 = 13.2 knots.

...right, back to that taskforce.

I always just make my best guess. After a while you will get good at guessing a ships speed. Its not easy and lots of trial and error... Mostly Error. But it works.