NAUTICAL SKILLS/ Anchoring
The Art of Anchoring
By John Phillips
Back in 1995 my wife and I spent the winter in the Caribbean on our Island Packet 31, C’est La Vie. One of our favorite places to anchor in the British Virgin Islands was in the bight at Norman Island. The weekends were always a busy in the BVI’s as a new batch of people arrived to take control of their bareboat charter. On these days we always made it a point to arrive at the bight and be anchored by 4 pm. This gave us time to take a quick swim and then shower and sit back and watch all of the charter boats come in and anchor. Some did a good job but most appeared to be learning for the first time. We called this the “Anchor Follies” and the later in the day it got the more entertaining it became.
On one occasion two older gray-haired couples came in almost at dark. The bight was thick with boats already anchored. They proceeded to drive by all of the anchored vessels heading for water where no boats were anchored. As they drove by our boat I told my wife, “I wonder if they know that there is a reef where they are heading.” I guess they didn’t because they proceeded to power the big Moorings 50-foot sailboat straight into the reef. The skipper then panicked and instead of putting it in reverse he pushed the throttle all the way forward. The noise was sickening and it took several of us in dinks to extract the boat from that mess. They finally anchored in a place off to themselves in quite deep water and I am sure they had an interesting conversation over dinner. All winter, the “Anchor Follies” never ceased to entertain us. It is especially entertaining to watch while sipping on a sundowner while listening to the 1812 Overture.
I have made my own mistakes in anchoring over the years but have come through all of them unscathed and with each one I learned something in the process. One mistake I made was when I anchored on a ledge on the southwest corner of Guadeloupe. The guide book said to make sure your anchor held on the ledge because the ledge was not large and it dropped off drastically. In addition, winds would come down from the mountains during the night with speeds up to 50 mph. And so I made sure the anchor was holding by backing down and taking compass bearings to three objects on shore. Around 8 pm the winds did come with gusts a little higher than 50 mph. Around three hours later they stopped and the wind settled into a gentle breeze. We turned in for a peaceful night’s sleep. Around 2 am my wife and I both work up and immediately knew that something was wrong. When we looked out of the companionway hatch we were shocked to see that we were about 2 miles offshore from our anchorage. We pulled up our anchor rode and anchor, started the engine, motored back to the anchorage, and anchored again around dawn. We were lucky but it was a valuable experience and from that point on I either set an anchor alarm or checked the anchor at various times during the night.
Few sailing experiences are as scary as waking in the middle of the night with the wind blowing hard and your boat is dragging anchor toward rocks, the shore, or another boat. On the other hand, there is nothing that gives you a sickening feeling as much as waking up to find another boat dragging down upon you or getting tangled in your anchor line.
Good anchoring technique is crucial for safety. Yet all too often even experienced sailors are in too much of a hurry and skip one of the important steps for anchoring securely. Some new sailors never learn the essentials and just toss the anchor overboard and assume they’ll be fine. Follow these guidelines to help ensure your boat is safely anchored so you can get a good night’s sleep.
Prepare in Advance
Study your anchorage using an uptodate chart. Turn on your VHF and get an updated weather report, paying special attention to the forecasted wind direction and speed. Determine the tidal effect on the depth and currents. Pay special attention to the chances for a shift in wind direction or speed. If your boat is pulled in the opposite direction during the night because of a reversing tidal current or wind, the anchor may be pulled out.
The ideal anchorage area should give you protection from the wind and waves and it should not be against a lee shore in case the anchor drags. The ideal bottom is sand or mud, not rock or heavy seaweed or grass. Most cruising guides and some charts show good anchorages that are protected and have good holding ground. Charts also show bottom characteristics when known. Study these and identify several possible options for anchoring before you leave the dock. By the way, you should review your plans with your first mate so that you are in agreement and both know what will be expected.
Get the anchor ready before making your approach. If the anchor rode is not marked at progressive depths with tags or color codes, stretch it out back and forth on deck so that you know how much rode you are letting out when anchoring.
Pick Your Spot Carefully
Survey the anchorage for other boats around the first planned spot you identified when you did your planning. It should have a depth which is a few feet deeper than the draft of your boat (at low tide) to as deep as 30-40 feet if necessary. Make sure you are well clear of any channel regardless of how the boat swings with wind shifts, and that there are no hazards if your boat were to swing in a full circle around the anchor. When other boats are already anchored nearby, follow good anchoring etiquette to stay safe without risking collision or entanglement. The general rule is that the first boat in an anchorage can choose its spot at will and each subsequent boat must stay clear of others already present.
Calculate how much swinging room you may need if the wind changes, based on how much anchor rode you will pay out. If possible, make sure your swinging circle does not overlap with any other boat’s swinging room. In a crowded anchorage where your swinging room may have to overlap another boat’s, choose a spot among similar boats. Most cruising sailboats with a full keel will swing in the same direction at the same time and therefore should not collide if not positioned too close together. But a shallow-draft powerboat will swing on the wind differently from a keel sailboat, increasing the risk of collision if their swinging circles overlap.
Although you can learn to anchor under sail, I think that is a risky proposition to pull off unless you are the only boat in the anchorage. Most cruising boats lower or furl the sails before making the approach into the anchorage and anchor under power. Using the engine also gives you more control if you need to make a last-minute maneuver. Approach your planned spot into the wind, keeping an eye on your depth finder or chart plotter to ensure you are where you want to be on the chart. If there is a strong current in the area that affects the boat more than the wind, approach into the current instead.
As you near the spot, slow down to allow the boat to coast to a stop. At this point you should not be in a hurry so don’t overrun your spot. Double-check to make sure you are not too close to another boat and are at the intended depth. If you decide you need to move to either side, circle back around to make your approach again to the new spot upwind or current.
Lower the Anchor
Wait until the person at the helm says the boat has stopped completely and is starting to move backward on the wind or current before lowering the anchor. If the boat is still moving ahead, you may accidentally set the anchor in the wrong direction by pulling it ahead instead of drifting back to set it.
It is important to lower the anchor gradually to prevent the anchor rode from falling down on the anchor flukes and possibly fouling the anchor. If you have an anchor windlass you can simply step on the down button or release the windlass brake. If you don’t have an anchor windlass just lower the rode hand over hand in a controlled speed. Never just toss the anchor over and hope for the best!
You can tell when the anchor reaches the bottom because of the reduced strain on the rode. Let out more rode to say a 5 to 1 ratio. Pause a moment to let the boat move back and pull the rode tight. If the boat is floating motionless in the absence of wind and current, tell the person at the helm to put the engine in reverse to start the boat backward. Your goal here is to align the anchor correctly on the bottom, with its shank pulled back in the direction in which the boat will lie at anchor. Otherwise, the anchor chain may foul the shank or flukes and prevent the anchor from setting well. One thing I will point out here. Although both husband and wife should be able to do both jobs, I think it works best if pink is at the helm and blue is at the pointy end.
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. If you don’t have any chain I would recommend adding this to your list of things to buy, as an anchor rode that is line only cannot pull horizontal along the bottom without some other means to weight the line down.
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 should 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.
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 if you have that much anchor rode. 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. I usually start with around 1200 rpms and then increase it to 1500 rpms. 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 make sure you will remain far enough away from other boats or hazards. Now cleat off the anchor line or if you have chain attach a snubber. In either case take the pressure off of your windlass.
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. If your GPS has an “anchor alarm,” learn how to use it and set it. A smart phone or tablet app like My Anchor Watch can also help ensure you know it if your anchor is starting to drag.
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.
Anchoring involves a number of skills, which improve with experience. Many books have been written on the subject and in this article we have only reviewed some basics. It is a good idea to keep a book on anchoring or seamanship on board to consult for appropriate techniques in unusual circumstances. If you are participating in an NSA event and you are not familiar with the proposed anchorage ask the cruise captain for information or post a question on the community forum. Or post your question in the social portion of our website if a circle was established for that event. Someone will probably be able to give you good advice. For those of you who like more visual explanations click herefor a good YouTube Video on how to anchor a sailboat. There are lots of videos on YouTube on all sorts of topics. There are even some funny videos as well.
If you follow the advice given in this article you should be able to safely anchor and get a good night’s sleep. And don’t forget to get their early so that you can anchor, make your sundowner, put on your favorites tunes, and watch the other boats come in and anchor. You just might be entertained watching some of them do the “Anchor Folly Dance.”
About the Author
John Phillips, the NSA's Vice Commodore for Finance, was first introduced to sailing at the age of 9 in an Optimist pram and he has been sailing ever since. He has owned or co-owned six boats and has done extensive lake sailing, coastal cruising as well as cruising in the Caribbean both as a skipper on bareboat charters to cruising for a year on his own boat. He currently sails his Island Packet 350, Chardonnay, out of Pecan Grove Marina in Oriental, NC.