5. Set the Anchor
Making sure the anchor is well set (that is, dug in well in the bottom) is the most important part of anchoring. The anchor holds the boat by digging its flukes into the bottom, not by just lying there like a weight on the bottom. If the anchor is not set, the boat may seem well anchored until the wind comes up—when the anchor will then bounce along the bottom as the boat drags toward a hazard.
As the boat moves backwards due to wind, current, or the engine’s power in reverse, gradually pay out the rode. Always keep a light tension on the line, but don’t yet clinch it tight. (If you tighten the rode too soon, the anchor will be pulled upward and out of the bottom and will not set.)
Visualize the anchor rode pulling straight back on the anchor shank as the point(s) of the anchor fluke(s) dig in. If your anchor rode is all chain or has a section of chain at the anchor, the pull will be more nearly horizontal along the bottom. This is how anchors are designed to dig in and hold.
When you have about 3 times as much anchor rode out as the water depth (a scope of 3 to 1), temporarily cleat or cinch the anchor rode at the bow and let it pull tight. Keep a hand on the rode to feel the tension. The boat should stop and the rode feel very tight, indicating the anchor has set. If the anchor has not set, you will feel the tension in the rode come and go or feel its pull changing as the anchor bounces along the bottom.
If the anchor has set, continue with the next step of paying out scope. If it has not set, you can also continue but must be very careful to ensure the anchor digs in when you have the proper scope. If the anchor has not set yet with about a 3 to 1 scope, many sailors prefer to hoist it now and try again rather than letting out more anchor rode and having to bring it all back up to try again later.
6. Pay Out the Proper Scope
Continue paying out the rode as the boat moves backward, until you reach the desired scope. Many factors affect the scope needed, including the type of boat, the type of anchor, whether the rode is all chain or a combination of chain and line, the characteristics of the bottom, and the wind predicted.
As a general rule, most cruisers prefer a scope of 7 to 1 for safe anchoring overnight. For a lunch stop in a calm anchorage, a scope of 5 to 1 or less may be sufficient, assuming someone stays on the boat in case the wind increases dramatically. With higher winds or big waves, a scope as high as 10 to 1 may be appropriate. Remember that the scope should be based on the high tide water depth. If you anchor at low tide in 10 feel of water and the depth 6 hours later is 20 feet, your scope then would be only half of what it was.
Once you have the proper scope, back down hard on the anchor using the boat's engine to ensure it is well set. The rode should be very tight and not give at all while backing.
Scope can be adjusted later if conditions change, simply by letting out more rode if desired. This increases your swinging distance, of course, so you should confirm you will remain far enough away from other boats or hazards.
7. Check the Anchor Periodically
Even when you’re sure the anchor is well set, changing conditions can result in the anchor dragging. Before relaxing completely for the night, make sure you can tell later on if the boat is dragging.
Your GPS or plotter can reveal changes of position, although small changes may not be noticeable or may be interpreted as just swinging in a different direction. If possible, take sightings on at least two features on shore (choose something that will be visible at night) and note the compass bearings to each. If these bearings change significantly later, you may be dragging.
Another technique used by old-timers is to let down a small second anchor or weight from the stern just to the point where it rests on the bottom, and then drape it over the boom and dangle a noise-maker like a bucket or pot tied to the free end. If the boat moves very far, the line will pull the noisemaker over the boom to clang down into the cockpit, hopefully waking you to take action if needed!
If you suspect you may be dragging, check the anchor rode at the bow. You may feel or see changes in its tension if the anchor is bumping over the bottom. If you have any evidence of dragging, monitor the situation very carefully. In calmer conditions the anchor may reset, but with gusty or heavy winds it will likely not dig in by itself, and you may have to hoist the anchor and move to a new position and start over.
Finally, in an emergency situation if the anchor is dragging or a gale puts you at risk of dragging—particularly against a reef or lee shore—you can avert disaster by running the engine slowly in forward gear to take some of the strain off the anchor rode.
A common anchoring problem occurs if the anchor's flukes hook under a rock, chain, or other bottom debris and prevent the anchor from being hoisted. Try backing pulling the anchor up from the opposite direction in an attempt to free it. The best solution is to use a trip line or the AnchorRescue retrieval device to prevent the risk of losing your anchor should it become snagged.
Anchoring involves a number of skills, which improve with experience. Many books have been written on the subject, and when cruising in unfamiliar waters or far from home where you may be caught in a tricky situation, it’s a good idea to have a book on anchoring or seamanship on board to consult for appropriate techniques in unusual circumstances.
Related articles:
How to Moor a Sailboat
The New Rocna Anchor vs the Classic CQR
