welcome to the Atlantic!
1) there is nefelodamon's tutorial about hunting only by hydrophone. you can get range, bearing and speed by some drawings.
http://nefelodamon.blip.tv/
2) when surfaced I follow my target and take some readings (4-5 at least), then I draw the line onto the nav-map and guess the speed by the time elapsed. drawing will be needed to get the AOB90 as well.