Hi h.sie,
the main differences are:
'1) My "friend" here can move at varied depths and even surface.'
Sergbuto's u-boats are either submerged or surfaced.
'2) He can be spawned by radio messages once you sight a convoy.'
Sergbuto's u-boats only appear when scripted in the campaign layers. There is no connection to the player's action.
I guess Iambecomelife uses the 'airplanes' to simulate the sub. If I am right, it would be great because you could create 'airbases' in the atlantic with u-boats as the only 'squadrons'. Then if you send a contact report there is a chance that u-boats are spawned and attack. So, sending a contact report could result in some kind of wolfpack action
And all you need is to add some airbases to the campaign_lnd layer (and the airbase definition and sub 'airplane').
It seems to be great work from Iambecomelife. I hope he releases something soon. It seems to be a great step towards better wolfpack actions.
Cheers, LGN1