[Teemu]

I quote the book Iron coffins by Herbert Werner. His boat was posted to patrol grid square BD95.

May 2 [1943]. ... At 1408 Riedel spotted a fast-moving target behind the southern horizon, a loner. We raced at highest speed on a track that would intersect the vessel's mean course. After three hours of running, during which we left the cargo ship cautiously behind the horizon, we dived leisurely, having plenty of time before the vessel would become visible. One hour later, our hopes of shooting the first torpedo vanished. The ship was identified as a Swedish freighter traveling the "Philadelphia Route", which we had guaranteed as a safe path for neutrals.

I have never heard of a "Philadelphia route". What was it?

[Sniper_1]

Teemu,

There were certain 'routes' across the atlantic which the combatants agreed could be used by neutral shipping for safe passage, so long as the neutrals were not engaged in shipping war material for one of the combatants. Irish and Spainish ships used these routes mostly, though Swedish and Swiss shipping used them too. I know Swiss shipping? sounds like an oxymoron, but the Swiss did have a merchant marine (despite being land locked, they used portsa in Italy and France for trade).

Sniper_1