VIIB vs VIIC

[XXi]

Yesterday, I`ve just finished a D2 patrol that took place between Januray 7th 1943 and July 12th, 1943.
I was to patrol near Capetown, then headed for the Indian Ocean, stuck near Mogadishu and Sansibar for some time.
I got a small convoy near Freetown, and several single merchants all over Africa - the play was just GREAT.
My lat three torpedos made all the true excitment of the patrol - I attacked a small convoy and all the torpedos annihilated a single Liberty.
However, there were three DDs, clear water.
I got pinged, so I started quick dive - if I`m beeing pinged already, what the reason to maintain periscope depth ?
At 85m I `ve slowed down and waited a bit. During the attack run, I dropped a decoy, got at flank speed, turn 80degrees, 120 m, than silent running.
And that was it - decoy has done its work.

So, even IXD2, when handled well, can be smooth - I go to flank speed, and when the plane is diving I made a sharp turn ( use Flak sometimes, depending on conditions ) - after the plane drops bomb, I start the crash dive so that usually I manage to get under water before it repeats the attack.