a large force of slaves
The answer to your question is found right there. White slave owners knew that "a large force of slaves" was a dangerous thing. They took action to ensure that slaves could not organize.
1680 - Virginia’s General Assembly restricts the ability of slaves to meet at gatherings, including funerals. It becomes legal for a white person or person to kill an escaped slave who resists capture. Colonial Williamsburg (hat tip to the scholar user2448131; I'm ashamed to have missed this.)
As a matter of fact, I believe the last time I visited Williamsburg, the courthouse was trying the case of a slave who was arrested for violating this ordinance; the slave had stopped to listen to a street preacher, and unwittingly exceeded the number of slaves who were permitted to gather.
Pretty much throughout history, criminal activity takes place in small groups; every additional member added to the group raises the risk of discovery, prosecution and execution. Given that slaves were property, and by definition had no civil rights, slaveholders had a wide variety of extreme measures available to suppress any attempt to organize slaves.
If I were a slave and wanted to escape, I would know that my success was based on how few people knew of my plans. I would not participate in any action by a large group of slaves.
The logistics of organizing slaves are staggering.
By coincidence the next day I heard Patrick Breen discuss Nat Turner's revolt - both professor Breen and Ms. Covart repeatedly reference the difficulty presented in organizing collective slave activity.