Anchoring is an art, or I should say, can be an art. Too many people think all it takes to anchor is tie off the anchor rope and drop it overboard.
Please don't be one of those people.
Depending on the size of your boat, failure to anchor properly can put your boat and safety in danger, it can jeopardize the safety of anyone else around you.
When approaching an area you wish to anchor, the most important first step is observation. Pay attention to any other boats in the area, how they are swinging on anchor, and what type of scope you may need to secure your boat.
How to Set an Anchor
Use Your Engine to Help When Anchoring
The proper technique for anchoring starts with easing the throttle so that the boat is basically standing still at the point where you want the anchor to drop. Let it go, sneak back under power, and slowly pay out the line.
Scope Out When Anchoring
You’ll need to know about how much scope you'll use, since this will affect where the boat will lie once the hook is stuck. The amount of scope is dependent on three things; what your anchor rode is made up of (all chain, chain+rope, all rope), the expected weather/wind, and your intentions when anchoring. Because of all the variables, how much scope you decide to put out is completely your responsibility. If you unsure, ask an expert. As a few suggestions; If you're just stopping for lunch on a calm day, 4-to-1 ratio might be OK (4 feet of anchor rode for every 1 foot of water depth). If you're spending the night on the hook, you'll want 8-t0-1 at a minimum. Any wind and weather will increase this need.
Head into any significant wind or current for positioning
At dead-slow speed, head the boat up into the wind or current, beyond the spot where you want the boat to lie, at a distance equal to your estimated scope. Come to a stop. In rough conditions, it can pay to drift back without dropping the boat anchor first, so that you can see where the boat will end up when you do deploy the hook.
Put out your rode and set the anchor
When enough rode is out to equal the desired scope, snub up on the cleat. Allow the stretch to come out of the line and see if you are holding. A shot of reverse gear can often help set the anchor hook but, if done prematurely, can cause the boat anchor to skate across the bottom without catching.
Make Sure Your Anchor Holds After Anchoring
With the hook set, cleat it off securely and run the rode through chocks to ensure that navigation lights and other deck equipment don’t get “swept” by the rode as the boat swings on the line. Line up with two landmarks, or use your radar, GPS or depth sounder to monitor your position and ensure that you are not dragging the anchor.
Know the Bottom Structure and have the right type of anchor
Your chart or plotter will generally show what to expect, but pockets of the unexpected do occasionally show up in an otherwise defined bottom to make life exciting. The most common bottoms are sand, mud, clay and grass (or weed). Most of the popular anchor styles (Danforth, CQR, Delta, Spade, Bruce, Rocna) are considered to be workable for all of these conditions. That said, plow anchors — like a CQR or Delta — hold best on a rocky bottom, a Danforth holds best in mud, and heavier anchors hold best in grass.
Suggestions for the Best Anchor Size When Anchoring
The boat anchor should be correctly sized for your boat. For instance, a typical 32-foot medium displacement boat could put out a 25-pound CQR or a 22-pound Delta and be comfortable in 30 knots of wind. A 12-pound Hi-Tensile Danforth is another option. One size up would be nice, especially if you have a power windlass to do all the work. Check the anchor manufacturer’s guide for your boat’s length, displacement and hull type.
Should you use Rope or Chain When Anchoring?
A properly sized all-nylon rode, either twisted or braided, is fine for light-duty anchoring. More common would be to add 6 to 8 feet of chain between the anchor shank and the rode. But for overnighting or extended anchoring, a one-half boat length’s worth of chain is a good rule of thumb to help an anchor’s holding power. The chain will aid in setting the anchor and keeping it set by lowering the angle of pull, thus helping to absorb the shock of a tossing boat due to wind or sea conditions and reducing chafe due to rocky or shelly bottom.
Be Courteous of Other Boaters in the area
If you’re the first or only boat in the anchorage, you’ve got priority. Otherwise, choose your spot carefully so as to allow enough swinging room to stay clear of the others and show your anchoring etiquette. Remember that big boats swing slower and tend to have a bigger arc than smaller ones. Boats with a lot of windage (big canvas enclosures, large cabins, high freeboard and almost all sailboats) will swing faster in high winds.
Once your anchor is set and you settle in, Check reference Points When Anchoring
Be sure to continue to check reference points, and watch to see that your position doesn’t change. Set the boat anchor alarm on your GPS, if yours has one, to alert you if something changes while you’re asleep or occupied. Then break out the sandwiches and enjoy the view.
The Windlass is Not a Cleat
The techniques in boat anchoring are the same, with or without a windlass. Keep in mind that a windlass is not a cleat and shouldn’t take the load of your boat under anchor. Neither is it the raw muscle to pull the anchor. Instead, take up the slack as you slowly motor forward to break the anchor free. Secure anchors hauled with windlasses with a trace of line or a chain stop.
Using an Anchor Snubber
At its most basic, a “snubber” is a short length of non-stretchy cordage attached to the anchor chain and to a strong point on a yacht, with the aim of taking the load off the windlass or to stop the chain rattling on the bow roller. A windlass is not designed to take snatch loads, nor, typically, is the deck to which it is attached
More commonly, the term snubber describes a long piece of cordage that cushions the boat from snatch loading. Typically, nylon rope is used for a snubber. Nylon stretches about 40 percent at breaking point, but about 10 percent is considered the safe working load limit (WLL). The more cycles above 10 percent of WLL, the shorter the life. Nylon’s elasticity is a function of weight—the thinner (less weight) it is, the easier it will stretch—and by measuring weight per meter it is possible to calculate extension.
Nylon is not the only cordage you can use as a snubber. Polyester is also suitable, although it lacks the degree of elasticity of nylon, so you will need longer lengths to achieve the same performance. In the unlikely event you cannot source nylon, then polyester is an alternative, but nylon is the most suitable.
When you rig the snubber you need to let out some slack in the chain, between chain hook and bow roller, to allow the snubber to stretch. If you are really clever you can estimate that slack to be, say, 15 percent of snubber stretch. This then limits the amount of stretch to which your snubber can be exposed. If you have an “everyday” snubber on one side and a storm snubber on the other, you can arrange that your storm snubber comes into play when the everyday snubber reaches 10-15 percent—this then allows both snubbers to work together.
A snubber is not a panacea. It will not make a poor anchor reliable, though it will make it less unreliable. Snubbers are simply part of your ground tackle wardrobe, along with spare anchors, spare rode, rated shackles and so on. If your spare rode is a mix of chain and nylon, it does not need a snubber; the nylon spliced to the chain will offer the required elasticity.