Must have been too easy
There is some conjecture as to the sinking of U155. There was a program on SBS recently which pointed to it being rammed as the snorkel ,periscope were broken off & massive damage to the area just forward of the sail . There is a suggestion that the boat was scuttled after sitting on the bottom for a couple of days after surviving further damage from Depth charging.The forward hatch was the only hatch open suggesting that the crew had managed to escape.
There is a site,www.uboat.org that has information that the boat was sunk by the allies after the war.
U155 sunk 26 ships ,2 of which were oil supply ships off the Florida coast.
It also sunk HMS Avenger just after it cleared the strates of Gibraltar
This boat caused the deaths of over 900 men