DON'T BE A DRAG
Our very best tip about not dragging, is BE SURE YOU HAVE PUT OUT ADEQUATE SCOPE! This can't be repeated often enough or emphatically enough! What is adequate scope? You could use the formulas of three to one, seven to one, etc, but I say use this only as a guide line. It is not a religious imperative, and don't forget, when you apply the formula, add your bow height above water to the depth, AT HIGH TIDE to get the suggested amount. Deep water, you can reduce the proportion, shallower water, increase it. If wind is predicted, or a chance of wind, I can't believe that anything under 100 feet, even in the shallowest water, is not leaving yourself vulnerable. Bigger and heavier, put out more, anchorage too crowded, get out and find someplace else. Doesn't matter if you are the dragger or the draggee, the damage can be the same. You are safer in a more exposed anchorage, where you can put out the maximum, than to be in a tight place surrounded by other boats, all with limited scope.
Enter the anchorage, take a serious look around and choose the spot that keeps you clear of other boats if possible. Having the best protection is not as important as having a well set anchor with maximum scope. Drop the anchor, put out the amount you need to set it best, (every anchor has a different length at which it digs in best) and make sure it is set by slowly increasing the RPM to what you know is necessary to dig that anchor in. How do you know what this is? Get in and look at the anchor after it is set; if it isn't perfect, have the person left on the boat turn on the motor and again take up the RPMs slowly and keep pulling until you have achieved what you want. Note what the RPMs were and you have a base line. Did you ever watch a live sand dollar bury itself.? It slowly wiggles itself , almost just vibrates itself, and it literally wiggles itself into the sand. Your anchor will do the same thing, if it is a burying type. Some anchors simply pull up a mound to a size that they can pull up no more, and you are held, but you know that if there is a major wind shift, they will need to repeat this from the other direction. Which is why you want to allow yourself some dragging room. If you start your anchoring life in conditions where you can't get in and see the process, than pull on it with enough intensity that the person on the bow should see water coming by at a brisk rate. From there it is experience, if you never drag, especially when others around you do, you are probably doing it right. Every time you drag, you should KNOW you did something wrong. Once it is well set, then put out the scope you will need to keep you there, even in storm conditions.
Ask yourself, how many times you have dragged in the last year, the last five years, the last ten years. If you can't remember each and every time, (because there should be so few incidents) if it is more than a couple of times, even in ten years, you are doing something wrong. Dave says if you drag even once, you have failed anchoring. Even in squall conditions, unless 8 out of 10 drag, you better not blame the bottom. Compare your anchor to someone near who didn't move, compare the type and weight of chain, compare scope and technique. Figure out what you are doing wrong, so you will get it right, and go for years without incident, and so you don't have to run to a dock every time wind is predicted.