 However, by 21 September the operation had failed to dislodge German defenders from the southern Netherlands and open the seaway to Antwerp; the supply problem was at its worst.Using the opportunity to rebuild their strength, the German Army in the West was able to accumulate a strength of around 500 tanks and assault guns by late September, despite prioritization of new equipment for the Eastern Front.This was in stark contrast to the estimated 100 which had been available before.