The Black PIT and Missions

[Harbinger1]

I am playing The Black Pit and have finished ;The Gap Closers and Triumph of the Wolfpack. Do I have to return to my port/harbor to activate the next mission. I believe there are 4 missions for The Black Pit...is this correct? If so how do I activate the next missions?

[Karl the Gross]

Nonono... The next mission is The Torch, which obligate you to sink:
THREE Troop Transport
ONE Large Warship.

Near the coast of Morocco.