Answer re the torpedoes can be found here..
http://www.uboat.net/ops/monsun3.htm
to quote..
The size of Penang flotilla was limited to 5 U-boats due to the dockyard capacity. The Monsun boats were so short of torpedoes that U-532, U-188 and U-183 were ordered to embark strategic materials and come home via the patrol areas in the Indian Ocean.