Equipment Accumulation
The fact that Alcatraz also housed manufacturing came in handy for the crew for several reasons. Prisoners made various items for the US military, including furniture, clothing, and footwear. That is to say, there was an abundance of equipment available for use. The fact that most inmates at Alcatraz were there for murder-related offenses was also helpful. That suggests the guards kept a careful eye on everybody but that the gang could slip under the radar, provided they behaved.