I've been a long time SH3 player, but just bought SH4 with the UBoat missions addon today. I immediately hopped in to a Gar class boat and went on a career. The first mission was to go to the Marshall Islands and have a free-style hunt. This isn't the Atlantic though and I get a little bored so I decide to see what harbour raiding is like in SH4
Before I get to the Tokyo area though, I get a report of a task force on a course which allows me to get below the thermal and come up on them. I first get a few destroyer escort hydrophone readings, and then things go quiet. Then all hell breaks loose on the hydrophone. This task force has a lot of warships, and even some merchants in support.
I close in using the classic method of go deep, wait for the screen to get in the right position and then go to periscope depth. This is what I see before me...

Yes, a fleet of carriers... Two Shokaku fleet carriers and two escorts, with loads of other ships around. On raising of my periscope, I discover the lead Shokaku is immediately on a good firing solution at about 4000m so as quickly as I could, I set tubes one and two to fast and just let them rip. I then sent two more to each of the two other carriers in the middle on fast settings.

I was a little giddy, so my screen shots don't show that much!
It wasn't long before the escorts were annoyed. Seven of them at one point.

It was surprisingly easy to get away though after I dived to max depth and got below the thermal layer.
Even though another carrier was still floating, I decided I had a good encounter and just legged it! I'm still on my way to the Tokyo area...