Contact Ranges and Contact Distances
 

Here are the speeds and distances your sonar man is telling you in the language your mother taught you in.:D

CONTACT RANGE IN METRES
Short range: 0-1,000
Medium range: 1,001-3,000
Long range: 3001-20,000



CONTACT SPEEDS IN KTS

Slow: 1-7
Medium: 8-18
Fast: 19-34
Very Fast: 35-

This holds true for everything except Merchants and Convoys medium and fast speeds which are:
Medium: 8-11
Fast: 12-

You realise that radio contacts from South China Sea reported while you're in Jawa Sea are also 'Long Range', right?

I think the key here is speeds and sitances your sonar man is telling you.