The Armstrong (AKA: 10 Boy Scouts) method can produce a fair amount of force and is very easy to set-up. If you have enough manpower, you probably don't need to set up anchors and you can use the full length of the rope. This approach mimics a tug of war and is often used in conjunction with someone turning the boat to have water pressure assist. It typically takes just a few minutes to set-up and you have fine control on how much pressure is applied. This method is an excellent choice for extracting a pinned boater and lowering or raising a rescuer in a vertical rescue.