:rotfl: that's a word. Lufthansa Cargo wasn't avail at these days...
I imagine a story where U-159 under the command of Kaleun Helmut Witte attacked an ammo ship from a distance of 250meters. The book says it was a 8000 tons freighter. After 30second nothing was left of the merchant. And the effect was...

let's say so: the book writes, that another submarine in a distance of 140kilomters said, they felt a strong wind and saw a thick cloud of smoke. I needn't to mention, that anything within the submarine was depredated and all glass was broken.
The attack took place south of capetown in late august '42.