The boats then traveled at an average speed of 5 mph over the Reichsautobahn (modern day A4 and A9) to the slipway in Ingolstadt. Traveling down the Danube, one obstacle[4] was the old Stone Bridge of Regensburg with its arches. Eventually, the submarines arrived in the Romanian port of Galați where they were re-assembled by the Romanians at the Galați shipyard.[5]