There are a number of tips that will help simplify your anchoring problems and develop your anchoring technique. Keep in mind that the design of your boat will affect its action at anchor. A shallow draft, planing-type hull will react more quickly to shifts in wind and is more prone to swing at anchor than a deep-draft powerboat or a deep-keel sailboat. A deep-keel boat will react faster to changes in current.
In a crowded anchorage, make allowance for the variance of different hulls to wind and current shifts. You may find, for example, that you cannot use the recommended average scope of 7 to 1 and may have to shorten to as much as 4 to 1. The shorter scope will naturally greatly lessen your anchor’s holding power. One trick you may use is to secure a weight approximately halfway down the anchor rode. This, in essence, will reduce the angle of line pull in reference to the bottom and reduce the chance of dragging anchor in the event it starts to blow. The weight is called a sentinel.
Don’t overlook the effect of tide. If you’re in an area, for example, with a six-foot tide and anchor in ten feet of water with 80 feet of line, your scope is 8 to 1. However, if the tide rises six feet, the scope is shortened to 5 to 1, which may be dangerous under certain conditions. A helpful indication of whether you have sufficient scope is to watch the reaction of waves on the rode. If an upward pull appears to be exerted as the bow rises, you have insufficient line out and should be wary of dragging anchor.
Always select two ranges ( landmarks or navigational aids) to fix your position. Watch these ranges for signs of dragging. The bearings also may serve to aid you in recovering your anchor if the line should part.