Checking if your interception course is right
 

This aviation website might come in hand. Just ignore the wind page and insert the fields with the data you gathered from a convoy or a single ship. Just add some extra knots on ownship to arrive before and have time to setup your attack.

http://www.luizmonteiro.com/RA.aspx

Very nice tool!

Unfortunately, on my boat, we have no iPad's, so back to the map plotting for them.

:yeah:

LOL Damo! Yeah... What's an Ipad? I play with this stinkin lousy yo-yo!!! If I'm lucky I can balance a tin can on a stick I hold between my teeth? I have a pencil, eraser, a protractor. We are blessed on U-51! Oh forgot that sextant we got from the quartermaster! Cost 2500 Deutschmarks!