Everyone knows that a sub on the surface moves faster then a sub underwater...

How can you use this to your advantage while engaged in battle?

This is how...

If you engage enemey sub at max range with slow torps.. and/or if you engage a
sub in such a way that your forced to turn your back to the sub"s"... Fire your torps,
then surface and turn away from the enemey. Wait for the enemey to fire its torps,
then you fire your rear torp in the direction you want to turn... so that if the enemey
sub turns the same way to attack you once it reloads... it will have no choice then to
either eat your rear torps in order to attack you again, or it will be forced to crit
dive. If the sub crit dives, you turn about and fight the sub head to head at max
range again. If the sub continues to attack you and eats your rear torp, continue to
drive away from the sub and repeat the same tactic already stipulated to...

Either way, do not submerge until you have the advantage from moving faster,
turning faster on the surface...