CURRENT FORCES
The loads exerted by currents are relatively Insignificant. A 5-knot current (a rare occurrence in an anchorage) would impose a load of around 340 pounds (150 daN) on a 40-foot (12.2 m) boat.
Current loads deserve consideration, however, especially when you’re anchoring in a river estuary or some other area subject to considerable tidal influence. When subjected to strong tidal currents, an anchored boat will swing successively in one direction, then the other. Checking tidal depth will allow you to ascertain if your boat will handle the swing at low tide without running aground. Every anchor type reacts differently to directional changes in the drag force. Some anchors pivot in place without breaking free from the seafloor, realigning themselves to the new direction of pull.