Spelljammer
Move Silently
This skill allows a character who makes a successful skill roll to move without making a sound. If hard-soled shoes are worn, the roll is at -20%. Maneuver penalties for armour also apply. A character may not move silently in metal armor. Perception rolls to notice someone who is moving silently depends on the character's Move Silently roll: PC +25 for Partial Success, 2x PC for Near Success, 1x PC for Success, and PC -12 for Absolute Success.