Anchorage, the technique of temporarily immobilizing a boat by dropping anchor, is a fundamental maneuver for any navigator. Much more than a simple technical operation, it is an art that requires precision, foresight and knowledge. A poorly executed anchoring can have serious consequences: collision with other boats, grounding on shoals, or damage to your boat and its environment.
Unfortunately, many boaters underestimate the importance of properly anchored. Among the most frequent errors, we note the choice of an inappropriate zone, an insufficient chain length or the lack of supervision once the anchor has been dropped. These carelessness can turn a peaceful stopover into a real nightmare, especially when weather conditions worsen.
This guide offers you a complete methodology to ensure safe anchoring, from preparation to monitoring, including recommended techniques and equipment. Whether you are a novice or an experienced navigator, these tips will allow you to calmly approach this essential navigation maneuver.
Preparing your anchorage
Choosing the right location
Careful choice of location is the first crucial step for a successful anchoring. Traditional nautical charts remain an indispensable tool, but modern navigation applications now offer remarkable accuracy and real-time information. Applications such as Navionics or OpenCPN can be valuable in identifying areas suitable for anchoring.
Always avoid high-traffic areas, such as port access channels or busy shipping routes. These locations expose your boat to an increased risk of collision. Likewise, beware of unstable bottoms or areas known for violent currents.
Meteorology plays a decisive role in choosing your anchorage. Check the weather forecast for the next few hours, or even the next few days if you plan to stay anchored longer. A bay sheltered from the dominant winds will offer you better protection. Remember to take into account tidal variations that can change the depth and currents considerably over the hours.
Verify the depth and nature of the bottoms
Once the zone has been identified, precise depth verification is required. Your electronic sonar is the most reliable tool for this measurement. For the most traditional ones or in the event of an electronic failure, a probe line (simple weighted and graduated rope) also makes it possible to obtain this crucial information.
The nature of the bottom directly influences the hold of your anchor. Sandy or muddy bottoms generally offer excellent stability, as the anchor can easily be buried there. On the other hand, rocky or coral bottoms present a double disadvantage: risk of your anchor permanently hooking and often random behavior. Grassy bottoms (Posidonia in the Mediterranean, for example) should be avoided because they offer poor stability and constitute fragile ecosystems to be preserved.
Technology can help you with this assessment. Systems like the Oria Marine IoT box incorporate advanced functionalities that allow you to precisely map the seabed and record favorable anchorages for your future stopovers.
Calculate the required chain length
The calculation of the chain length represents a decisive step for secure anchoring. The commonly accepted rule recommends a chain/depth ratio of at least 5:1 in calm conditions, which means five times the height of the water under your keel. For example, if you anchor at a depth of 4 meters and your boat has a draft of 1 meter, you will have to sail at least 25 meters of chain (5 × [4 + 1]).
This ratio should be increased in case of adverse weather conditions. In heavy seas or strong winds, a ratio of 7:1, or even 10:1, becomes necessary to guarantee optimal hold. This excess chain forms a curve (catenary) that absorbs shocks and considerably improves the horizontal holding force of your anchor.
Wind strength and current strength also influence this calculation. The more important these factors are, the longer the chain length should be. Some electronic systems such as the Oria Marine IoT box offer integrated calculators that suggest the optimal chain length based on environmental conditions in real time.
Mooring techniques
Lay the anchor correctly
The wetting procedure takes place in several well-defined steps. Start by reducing your speed until you come to a complete stop in your chosen zone, facing the wind or the dominant current. This position will make it easier to put the anchor in place and prevent it from turning over or getting tangled in its chain.
Lower the anchor gently until it hits the bottom. Once at the bottom, start backing up very slowly (with the motor or by letting the boat drift) while gradually spinning the chain calculated previously. This technique allows the anchor to sink properly into the substrate.
To check if the anchor has “hooked”, observe its behavior when you apply slight tension to the chain: a clear resistance generally indicates a good grip. You can also temporarily increase the power of the engine in reverse to test the handling (so-called “croc test”). If your boat remains stable despite this pull, your anchor is correctly positioned.
Then let the boat back up naturally until it stabilizes at the end of its chain. This movement allows the anchor to sink further under the effect of horizontal traction. Avoid forcing this movement with the motor, as this may dislodge the anchor rather than depress it.
Use a rope or fender
Orin is a rope connecting the anchor to a buoy floating on the surface. This accessory has two essential functions: to signal the exact position of your anchor to other navigators (thus preventing them from anchoring over yours) and to facilitate the recovery of your anchor if it gets stuck in the bottom.
To install a rope, attach one end of the rope to the diamond of the anchor (or to the place provided for this purpose depending on the model) before putting it into the water. Attach the other end to a buoy that is visible enough. The length of the river must correspond to the real depth under your boat, taking into account the high tide if you are in a tidal zone.
Fenders, usually used to protect the hull during berthing, can also play a role when mooring in a busy area. Placed strategically around the boat, they will minimize damage in case of contact with another boat. This precaution is particularly useful in crowded anchorages during the high season or during nautical events.
Check the anchoring behavior
Once anchored, establish visual landmarks on the shore to track your position. Identify at least two fixed points in line (a tree and a building, for example) that will allow you to quickly detect any movement of your boat. If these markings are out of alignment, it means that your anchor is skidding and immediate action is required.
Modern technologies now offer effective complementary solutions. Anchorage alarms integrated into GPS or marine applications alert you as soon as your boat moves away from a defined perimeter. The Oria Marine IoT box offers a particularly advanced mooring alarm function, capable of notifying you directly on your smartphone in the event of a drift, even when you are ashore.
Perform visual checks regularly, especially after a tide change or a change in weather conditions. These critical moments can affect your anchor's handling and require increased vigilance.
Behaviour to adopt at anchor
Rules of courtesy between boaters
Mutual respect between mariners starts with maintaining an appropriate safe distance. This distance depends on several factors: the size of the boats, the weather conditions and the space available. As a general rule, keep a minimum distance that is at least twice the length of the largest boat.
Before you drop anchor, observe the behavior of boats that are already anchored. Their position tells you the direction of the wind or the dominant current. Align with them to correctly anticipate the evolution of your own boat once at anchor. Keep in mind that each boat describes an avoidance circle whose radius corresponds approximately to the length of the spun chain.
If you need to anchor near other boats, contact their crews to make sure your position won't interfere with them. This courteous approach makes it possible to avoid misunderstandings and conflict situations, while promoting mutual assistance when needed.
Oversight and risk management
Constant monitoring of your position is an obligation, even once the anchoring has been established. If a drift is detected, react immediately by restarting the engine to relieve the tension on the anchor. If the anchor has in fact skidded, it will generally be necessary to repeat the anchoring procedure entirely in a more favourable area.
At night or in bad weather, be extra vigilant. Make sure your anchor light is on and visible (regulatory requirement). Also, prepare your safety equipment for quick intervention if necessary: life jackets within reach, waterproof flashlight, knife to cut the anchor line in case of emergency.
Connected technologies like the Oria Marine IoT box offer additional peace of mind thanks to their continuous monitoring and customizable alerts. Their use is particularly valuable during crew rest phases or during shore excursions.
Recommended equipment for safe anchoring
Types of anchors and their uses
Several types of anchors exist, each with specific characteristics:
- The flat anchor (Danforth type): light and compact, it offers excellent hold in sandy or muddy bottoms thanks to its large legs. However, its penetrating power remains limited in hard bottoms.
- The plow anchor (CQR or Delta type): versatile and reliable, it is suitable for the majority of funds. Its design allows it to automatically realign itself in the event of a change of direction of the boat.
- Anchor à Jas (Spade or Bügel type): offering excellent penetrating force and remarkable strength even in difficult bottoms, it often represents the choice of demanding sailors despite its greater weight and size.
- New generation anchors (Rocna, Manson, Ultra type): combining the advantages of previous models, they offer excellent hold in almost all types of bottoms, with an automatic repositioning capability.
The choice of your anchor will depend mainly on your usual sailing area. For coastal navigators in the Atlantic or English Channel, a plow anchor is often a good compromise. In the Mediterranean, where the funds are more varied, a new generation anchor will be more suitable.
Useful accessories
A complete mooring line includes several essential components:
- The channel : choose marine-grade galvanized steel. Its weight helps to keep the anchor flat on the bottom, thus improving its hold. For a standard pleasure boat, a chain of 8 to 10 mm in diameter offers a good compromise between strength and weight.
- The rope : it extends the chain for deep anchorages. Opt for a nylon rope that absorbs shocks thanks to its natural elasticity. Its diameter must be adapted to the size of your boat (generally between 14 and 18 mm).
- The anchor buoy (or Orin buoy): choose a model that is sufficiently visible and robust. Some models incorporate a radar reflector to increase their visibility in foggy weather.
- Anchorage alarm : an accessory that has become indispensable, it can take several forms. Dedicated systems such as the Oria Marine IoT box not only offer the alarm function but also the recording of mooring data for subsequent analysis and the continuous improvement of your techniques.
Special cases and professional advice
Anchoring in a busy area
In popular anchorages such as Mediterranean coves in summer or popular bays on the Atlantic coasts, the space available is considerably reduced. Under these conditions, reduce your avoidance circle slightly by decreasing the chain length (while maintaining a minimum 3:1 ratio). Compensate for this reduction with increased surveillance.
Arrive early in the day for a better choice of location. Choose peripheral areas, which are generally less congested and offer better tranquility. If you plan on staying for several days, using an auxiliary floating anchor can limit your avoidance circle and further secure your position.
Anchorage by high wind
Faced with difficult weather conditions, adapt your technique. Increase the length of the spun chain substantially (7:1 ratio minimum). Carefully check the initial hold of the anchor by applying strong rear traction to the engine.
Prepare a second anchor ready to be quickly wet if necessary. Maintain a constant watch, establishing a guard shift between crew members if necessary. The use of an electronic surveillance system such as the Oria Marine IoT box becomes particularly valuable in these conditions, in particular for its early warning in the event of a drift.
Double your anchoring (anchoring in line or in V)
For maximum safety during extreme conditions or for prolonged anchoring, the use of reinforced anchoring is essential:
- Anchorage online consists in deploying two anchors one behind the other in the wind or the dominant current axis. Wet the main anchor first, and then, after backing up a sufficient distance, deploy the second. This configuration effectively limits the risks of slippage.
- The V-anchoring involves the deployment of two anchors forming an angle of approximately 45° to 60° with your boat. This arrangement considerably reduces the avoidance circle and provides excellent resistance to changing winds.
These advanced techniques require regular practice to be mastered. Do not hesitate to train under favorable conditions before implementing them in critical situations.
FAQS
What length of chain do you need to properly anchor your boat?
The optimal chain length is generally 5 times the total depth (bottom + draft) under calm conditions. This ratio should be increased to 7:1 or even 10:1 in case of adverse weather conditions or for long-term anchoring.
Can you wet everywhere?
No, some areas are forbidden to anchor for various reasons: presence of submarine cables, military zones, natural reserves or proximity to navigation channels. Always consult nautical charts and respect marine signs before anchoring. In the Mediterranean, Posidonia meadows are particularly protected and anchoring is often regulated.
What should I do if my anchor skids?
If your anchor skids, start the engine immediately to control your drift. Reassemble the anchor completely and inspect it for damage or debris. Choose a new, more favorable location and repeat the wetting procedure again. In critical situations, feel free to use your second anchor.
What is the best anchor for sandy bottoms?
The sandy bottoms effectively accommodate most modern anchors. The Danforth type flat anchor offers excellent performance on this type of bottom thanks to its large legs. New generation anchors such as Rocna or Spade also have remarkable stability in the sand, with the advantage of being more versatile on other types of bottoms.
How do I know if my mooring is well secured?
A well-secured anchoring can be recognized by several signs: the anchor has withstood the reverse pull test, your boat maintains a stable position in relation to established visual references, and the chain has a regular tension without sudden jolts. Electronic systems like the Oria Marine IoT box can confirm this stability by recording your movements over an extended period of time.
Do you have to stay on board when you are at anchor?
Permanent presence on board is not mandatory, but it is strongly recommended, especially if the weather conditions are unstable or if the anchoring is very busy. If you have to leave your boat, choose short absences and make sure that your mooring is perfectly secure. The use of a connected alarm system such as the Oria Marine IoT box allows you to be alerted remotely in case of a problem.
What equipment is mandatory for anchoring?
Maritime regulations require that a recreational boat be equipped with a complete mooring line including at least one anchor and a length of chain or cable adapted to the size of the boat. A white anchor light visible at 360° must also be on between sunset and sunrise when the boat is at anchor. Consult Recreational Craft Safety Division 240 for specific requirements that apply to your boat.
Conclusion
Anchoring a boat, far from being a simple formality, is a technical maneuver that requires rigor and methodology. From careful preparation to constant surveillance, each step contributes to ensuring your safety and that of other users of the sea.
Mastering this fundamental competence is based on a few essential principles: the careful choice of location, adaptation to environmental conditions, the use of appropriate equipment and constant vigilance. The adoption of modern technologies such as the Oria Marine IoT box can considerably facilitate this task by providing an additional level of security thanks to its monitoring and alerting functionalities.
Whether it's a temporary stopover or an extended anchoring, always keep in mind that the sea remains an unpredictable environment that requires humility and respect. Rigorous preparation and constant attention will allow you to take full advantage of these privileged moments that represent stops at anchor, while maintaining your safety and that of your crew. Navigating responsibly means, above all, anticipating and preparing for all eventualities.
