Newbie question, might have missed this at Rulebook

Yes… What I meant was, 1 regular submarine attack modified to disallow a casualty roll.

Your 4 Subs could attack the SZ with the Battleshop and Transport and you would get to roll for all 4 Subs.
If two hit, both the Battleship and the Transport will sink. The Attoeshio would get no defence shot.
If none or one hits, the Battleship would still be alive and would get one roll in defence.
On the 2nd Round the surviving Subs would get to sneak again.
The Transports sinks automatically when the Battleship sinks as long as one attacking unit(Sub in this case) is still in the SZ.

Perhaps your friend should be told a Battleship, or Carrier, should always be a accompanied by a Destroyer if there are Subs around.
Was it an oversight?

@Kloever:

But what about the IC? Can you just place as many as you like around the board? I know you can place just 1 in a zone.

Assuming you do not play Europe/Pacific/Global 1940 the rules are:

@rulebook:

Place new industrial complexes in any territory that you have controlled since the start of your turn and that has an income
value of at least 1. You cannot have more than one industrial complex per territory.

So yes, you can place as many as you like as long as you follow the quoted rules.

@Kloever:

She is attacking me by sea with 3 transports, a battleship and a cruiser. She hasnt reached my land yet. But she is in range of my bombers. Can i attack the fleet and so destroy here Battleship, cruiser and here Transport(inc cargo)?

Yes, you can destroy her fleet, providing the fleet is within reach of your bombers. “Within reach”, that means, you have to take into the account the total move value of the bombers (=6). You have to save some movement points for to land at a save landing spot in the non-combat movement phase. Example: if her fleet is 4 spaces apart of your bombers, then you will use 4 movement points to reach the fleet, with 2 movement points left to reach a save landing spot (friendly territory, friendly carrier or new mobilized carrier).

@Kloever:

Oke, i think last question. She is attacking me by sea with 3 transports, a battleship and a cruiser. She hasnt reached my land yet. But she i in range of my bombers. Can i attack the fleet? And so destroy here Battleship, cruiser and her Transport(inc cargo)?

If it is her turn you are the defender. As defender you can use your Bomber only (with a defensive shot) if it is in a territory attacked by her.

@ panther: …bearing in mind the formerly questions, you was well advised to differentiate between attacker and defender… :-D