I'm currently on my 3rd patrol. I already have found and sunk 2 ships. One was a one-shot torpedo kill, the other was a bit more difficult, mainly due to the bad weather and dud torpedoes, which forced me to follow the ship for a while until the weather cleared and i could kill him with my deck gun. I'm playing with everything turned on except manual targeting, map contact updates and external view. It's a nice balance between full realism and arcade.
BTW,the game is a blast! It's May 1942 and the Battle of Midway is going to start soon. I'm thinking of going to Midway and try to find the battle or perhaps even sink Japanese Carriers before the SBDs do.
That would make up for my poor early patrols. I'm probably going to die horribly though.