Depends on how you fish. One Power-Pole anchor will stop and hold a 4500lb, 28’ boat. With one Power-Pole anchor your boat will stop quickly but wind and water current will determine which way the bow of the boat will face. You will not spin in circles unless you are in the eye of a hurricane!
With two PP anchors you have total boat control and can position the bow of the boat in any direction despite the wind and the current direction.