While steaming at 20 kts in a simulator, we dropped a Search and Rescue Transponder (SART) in the water 6 minutes ago.
Measuring the range from our Own Ship to the SART, we see we traveled 2 miles in 6 minutes.
A line from the SART to our Own Ship would be a vector representing the direction our own ship is going plus the distance it covered in 6 minutes.
6 minutes is 1/10 of an hour so the 2 miles our ship traveled is 1/10 our speed.
The Time and Distance Review module has further explanations of figuring distance of vectors.