Anchoring and Mooring

Prerequisites

Before this lesson you should:

• Have Competent Crew level deck skills: handling lines, cleating, using a windlass or winch safely, and working on the foredeck.
• Be able to calculate the height of tide at a given time at a standard port, and understand chart datum, charted depth and drying heights (Day Skipper tidal heights lesson).
• Read seabed symbols on a chart and recognise the anchorage symbol.
• Understand basic boat handling under power: steerage way, prop walk, windage (Day Skipper boat handling lesson).

The RYA Day Skipper practical syllabus requires you to be able to choose an anchorage, anchor and weigh anchor under power, and pick up and leave a mooring buoy, briefing your crew for each.

Learning Objectives

This lesson covers the RYA Day Skipper shorebased syllabus topic "Anchoring Techniques" (choosing an anchorage, anchor types, scope, setting, anchor watch, weighing) and the practical syllabus items for anchoring and for picking up and leaving a mooring buoy under power. By the end of this lesson you will be able to:

• Choose a safe anchorage using the chart, almanac, pilot book and forecast (syllabus: choosing an anchorage).
• Recognise the main anchor types and the seabeds each suits (syllabus: anchor types and holding ground).
• Calculate the depth to plan for and the length of chain or rope to let out (syllabus: scope).
• Brief the crew and carry out the anchoring sequence under power (practical: anchoring and weighing).
• Confirm the anchor is set, and maintain an anchor watch (syllabus: anchor watch, drag detection).
• Work out the swinging circle and check it is clear at all states of tide.
• Recognise dragging and respond correctly, including deteriorating weather.
• Weigh anchor safely, and free a fouled anchor.
• Display the correct signals at anchor (COLREGs Rules 30 and 35) and know basic anchoring etiquette.
• Describe a second anchor, a kedge and a fore-and-aft arrangement, and when each is useful.
• Pick up, lie to and leave a mooring buoy, and understand mooring etiquette (practical: mooring buoy).

Choosing an Anchorage

What makes a good anchorage

Check all of the following:

1. Shelter from the wind and swell now and for the whole of your stay. Look at the forecast: if the wind is due to veer from southwest to northwest overnight, an anchorage open to the north is a trap.
2. Holding ground the anchor can dig into.
3. Depth: enough water under the keel at low water, but not so deep that you cannot let out enough scope.
4. Swinging room: clear of other boats, moorings and hazards as the boat swings through 360 degrees.
5. Not prohibited: no cables, pipelines, fairways, eelgrass protection zones or anchoring bans. The chart shows cables and restricted areas; the almanac and pilot book add local detail.
6. A way out: an easy route to sea if conditions change at night.
7. Landing: if you want to go ashore, somewhere safe to leave the dinghy.

Holding ground

The chart shows the seabed with abbreviations: M (mud), S (sand), Cy (clay), G (gravel), Sh (shells), St (stones), R (rock), Wd (weed). The diagram grades them.

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• Mud and clay: usually excellent once the anchor has dug in. Very soft mud can need more scope.
• Sand: good; firm sand is very reliable.
• Gravel and shells: variable.
• Weed: poor. The anchor can skate across the top on a mat of weed and never reach the seabed.
• Rock: poor and risky. The anchor may hook in a crevice and refuse to come out, or not hold at all.

Respect protected habitats. Seagrass beds (in the UK, for example, parts of Studland Bay and the Helford) are home to seahorses and other species, and in some places anchoring is restricted. Use visitor moorings or designated anchoring areas where provided.

Anchor Types

Different designs suit different seabeds. Most yachts carry a main (bower) anchor on the bow and a lighter kedge anchor stowed in a locker.

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Whatever the type, it must be big enough. Use the manufacturer's tables for your boat's length and displacement and, if in doubt, choose the next size up: an oversized anchor rarely causes a problem, an undersized one fails when you most need it.

Rode: chain, rope or both

The rode is what connects the anchor to the boat.

• All chain: heavy, so it lies along the seabed and forms a curve (catenary) that keeps the pull on the anchor horizontal and absorbs snatching. Resists chafe on rocks. The usual choice for cruising yachts with a windlass.
• Chain and rope (warp): a length of chain next to the anchor (at least 5 to 10 m, ideally more) then nylon rope. Lighter and stretchy, but needs more scope because there is less weight to keep the pull horizontal. Rope chafes on rocks and at the bow roller.

With all chain, use a nylon snubber (a short length of rope hooked on the chain and led to a bow cleat) to absorb shock loads and take the strain off the windlass. Never leave the windlass as the only thing holding the chain.

The bitter end of the chain should be tied inside the chain locker with a length of rope, long enough to reach the deck, so it cannot all run out, but can be cut free in an emergency.

How Much Scope?

Scope and depth

Scope is the ratio of the length of rode let out to the depth of water. The longer the rode, the more horizontal the pull on the anchor, and the better it holds. The diagram shows the geometry.

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The RYA rules of thumb:

Use more in strong winds or overnight: 5 to 7 times for chain, 8 to 10 times for rope in bad weather, if the swinging room allows. Let out less only for a short daytime stop in calm weather with someone on board and watching.

Which depth?

Two corrections are often missed:

1. Use the maximum depth during your stay, i.e. the depth at high water, not the depth when you arrive. Depth at HW = charted depth + height of high tide.
2. Add the height of the bow roller above the water, because the rode starts at the bow, not the waterline.

Also check the minimum depth: at low water, will you still float, everywhere within your swinging circle?

Marking the chain

Mark the chain every 5 or 10 m with paint or coloured cable ties so the crew can count what has gone out. Make sure everyone knows the code.

The Swinging Circle

At anchor, the boat swings round the anchor with every change of wind and tide. The radius of the circle she can occupy is approximately the length of rode let out plus the length of the boat.

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• Check the whole circle is clear of hazards and has enough depth at low water.
• Boats on different rodes swing differently. A boat on all chain swings less, and more slowly, than a boat on rope; a motor cruiser swings to wind, a deep-keeled yacht more to tide. Anchor near boats similar to yours, with similar scope.
• The first boat to anchor has priority. If you arrive later and your circle overlaps another boat's, it is you who must move.
• Do not anchor in a fairway or in the approach to a slipway or moorings.

Wind against tide

When wind and stream are in the same direction the boat lies quietly. When they oppose, the boat may lie across the wind, sheer about, and snatch at the anchor, as shown below.

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In an anchorage with a strong stream, expect the boat to swing right round at each turn of the tide, and the anchor to be pulled from the opposite direction. Modern anchors reset well; some older designs may not. Check the anchor holds after the turn.

Anchoring Procedure

Before you arrive

1. Choose the spot on the chart and check depth, seabed and swinging room.
2. Calculate the length of chain to let out.
3. Brief the crew: where you will anchor, how much chain, hand signals between the bow and helm (engine noise and wind make shouting useless), and who does what. Agree signals for: let go, stop, more chain, chain up and down, anchor holding, and anchor off the bottom.
4. Prepare the anchor: remove any securing pin, check the windlass works and the chain is free to run, and have the snubber ready. The foredeck crew wear shoes and gloves, keep fingers and feet clear of the chain and gypsy, and never stand on the chain.
5. Have the anchor ball (day shape) ready to hoist.

The approach

The sequence is shown below.

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1. Look at how other anchored boats are lying: that is the direction you will lie.
2. Approach slowly on the same heading as they are lying, into the stronger of wind or tide.
3. Stop the boat over the spot where you want the anchor to go.
4. Lower the anchor to the seabed under control, with about a third of the scope. Do not let it free-fall and pile the chain on top of it, which can foul the anchor; the RYA notes say simply "do not drop all the chain at once".
5. As the boat starts to drift back (or using gentle astern), let the chain out steadily, laying it along the seabed in a line rather than in a heap.
6. When about the planned length is out, check the chain gently (snub it) to start the anchor digging in, then let out the rest. Let the boat come to rest as the anchor bites, then set it with a short burst of astern power.

The RYA course notes summarise the whole sequence in five steps: approach into the wind or stream; drop the anchor and a third of the scope; drift back or go astern slowly, paying out the scope; let the boat come to rest as the anchor bites; set the anchor with a short burst of astern power. Then establish a transit to check that the boat is not dragging, and hoist the anchor ball or switch on the anchor light.

Setting the anchor

Do not assume the anchor is holding. Prove it.

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1. With all the chain out and secured (snubber on), go gently astern, then gradually increase to around two thirds of cruising revs (on a typical small yacht diesel, about 1500 rpm) for 30 seconds or more.
2. While going astern, watch a transit abeam (two objects ashore lined up, or a near object against a distant one). If the transit stays fixed, you are holding. If it opens steadily, you are dragging.
3. A hand on the chain will feel a juddering vibration if the anchor is bumping across the bottom.
4. When holding, take the engine out of gear. The boat should spring forward slightly as the chain's catenary pulls her back.
5. Hoist the anchor ball. Note the position and set the anchor alarm on the GPS.

If the anchor drags, raise it and try again, perhaps in a different spot or with more scope. Weed on the flukes when you raise it tells you why.

Signals at anchor

COLREGs require a vessel at anchor to show:

• By day: one black ball forward, where it can best be seen (Rule 30).
• By night: an all-round white light forward (vessels under 50 m). A vessel under 7 m not in or near a channel, fairway or anchorage is exempt.

In restricted visibility, a vessel at anchor sounds a rapid ringing of the bell for about 5 seconds at least every minute (vessels 12 m and over; smaller vessels must make some efficient sound signal).

Anchor Watch

Checking you are not dragging

Keep checking, especially when the wind rises, the tide turns or at night.

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Methods:

• GPS anchor alarm: set a radius a little larger than your rode length plus the boat length, centred on the anchor (not the boat's position when you set it).
• Transits and bearings: note two or three clear compass bearings of fixed objects ashore. Check them regularly. Remember the boat swings, so a small change is normal; a steady change in one direction means dragging.
• Depth: note the expected depth range from the tide calculation. A depth outside it means you have moved.
• Feel: a hand on the chain will feel vibration if the anchor drags over hard ground.
• Look: at night, other boats' anchor lights and lights ashore should stay in the same relationship.

If you drag

1. Act immediately. Dragging rarely stops by itself.
2. Start the engine, call the crew, and check nothing is round the propeller.
3. Motor gently up towards the anchor to take the strain off, and let out more chain if there is room. If it still drags, weigh anchor and re-anchor, or leave.
4. At night, a dragging boat in a crowded anchorage is a danger to others. Have a plan for where you will go.

In strong winds overnight, set a formal anchor watch rota, with clear instructions on what to check and when to wake the skipper. The watchkeeper needs warm clothes, a torch and a log.

Weighing Anchor

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1. Brief the crew and agree hand signals. Start the engine and check the engine instruments and cooling water.
2. Remove the snubber.
3. The helm motors slowly towards the anchor in the direction the chain leads (the bow crew points to show where it lies; it is useful to know this before you start), while the bow crew brings in the slack. The windlass should only lift the weight of chain; never use it to drag the boat forward. Motor too fast and the chain or rope may end up round the propeller.
4. When the chain is vertical ("up and down"), signal the helm. The anchor usually breaks out as the boat moves over it. If not, snub the chain and let the boat's motion or a little forward gear break it out.
5. Signal "anchor off the bottom": the boat is now under way and the helm must take control.
6. Bring the anchor up, washing mud off the chain with a deck hose or bucket as it comes in. Check the anchor for damage or fouling and stow it securely on the roller with its pin or lashing. A loose anchor can swing and damage the bow, or drop in a seaway.
7. Lower the anchor ball.
8. Stay in sheltered water while the anchor and chain are washed down and put away (a bucket and brush are needed if the anchorage is muddy), and make sure the anchor and the anchor locker are secure before putting to sea. An anchor that breaks loose in a seaway can hole the bow.

A fouled anchor

If the anchor will not break out, first secure the cable on a cleat or the chain stopper (not on the windlass) and motor gently forward over it to break it out with the boat's weight rather than the windlass. If that fails:

• Motor slowly in a circle round it, keeping the chain short, so the pull comes from different directions.
• Motor forward past it and pull from the opposite side.
• If you rigged a trip line (a line from the crown of the anchor to a small buoy on the surface), haul the anchor out backwards by the crown. In an anchorage known for old moorings or rocks, rig a trip line before you anchor.
• Last resort: if the boat or crew are at risk, buoy the end of the chain and slip it, then return later with a diver.

Never risk a crew member's fingers or the windlass trying to haul a jammed anchor by brute force, and never cleat the chain while motoring hard ahead over it.

Mooring Buoys

Types of mooring

Many harbours have visitor moorings: a buoy (often marked "visitors" or coloured, e.g. yellow) attached by a riser chain to a heavy ground chain or block on the seabed. Some have a pick-up buoy with a line, others just a ring on top. Fore-and-aft moorings (bow and stern buoys) are used in narrow rivers to stop boats swinging.

Never pick up a private mooring without permission: it may not be strong enough for your boat, and the owner may return.

Picking up a buoy under power

1. Look at how moored boats are lying: they show the combined effect of wind and tide.
2. Approach on the same heading, slowly, into the stronger of wind or tide.
3. The bow crew points at the buoy throughout, because the helm loses sight of it under the bow, and signals distance.
4. Stop with the buoy beside the bow, ideally on the side the helm can see.
5. The bow crew picks up the pick-up line with the boathook, or threads a mooring line through the ring and back to the boat, and makes it fast to a bow cleat.
6. For a stay of more than a few minutes, use two lines, or a line plus a chain strop, so a single line cannot chafe through. Lead them through the bow roller or fairleads, not across sharp edges.

Do not try to hold the boat with the boathook, and never put hands or feet between the boat and the buoy.

Lying to and leaving a mooring

• A boat on a mooring swings like one at anchor, though in a smaller circle. Check your neighbours.
• Ring-topped buoys can bang against the hull in wind against tide; tie a fender or let out a little more line.
• To leave, rig the line as a slip (both ends on board), start the engine, then release one end and pull it through, keeping it out of the water and away from the propeller. Drop back or motor off on the side away from the buoy.

Picking up a buoy under sail

Approach on a close reach, or from directly downtide if the tide dominates, with the headsail furled and the mainsail eased so you can control speed: sheet in to accelerate, ease to slow. Stop with the buoy at the bow. Only try this after practice, ideally on a fender in open water first.

Anchor Size and Rode Strength

The anchor and rode are chosen as a system. The manufacturer's table gives a recommended anchor weight by boat length and displacement for a design wind (typically a gale, Force 8). As a very rough guide for modern high-holding anchors, a 10 m cruising yacht of 6 to 7 tonnes would carry an anchor of about 15 to 20 kg, and an older design such as a CQR or Bruce would need to be a size larger. Always follow the maker's table for the specific model rather than a rule of thumb.

Chain size follows the anchor: 8 mm short link chain is common on yachts of 9 to 11 m, 10 mm for boats of 12 to 14 m. Chain of the wrong gauge jams the gypsy and jumps off the windlass, so match it to the windlass. For a chain and rope rode, use three-strand nylon, which stretches and absorbs shock; the diameter is typically 14 to 16 mm on a 10 m yacht.

Why chain lies low

Chain is heavy, so on a good scope the part nearest the anchor lies flat along the seabed and the pull on the shank stays horizontal. Only in strong wind does the chain lift off the bottom and straighten, using the weight of the lifted chain as a spring. This is why all chain holds better at 4 to 1 than rope does at the same scope, and why a rope-only rode needs a heavy length of chain to keep the pull low.

The snubber and bridle

A snubber is a length of stretchy nylon about one third of the boat's length, attached to the chain with a chain hook or a rolling hitch and led to a bow cleat, with the chain then eased so the snubber carries the load. It protects the windlass and stops the boat snatching. A bridle spreads the load between two bow cleats or fairleads and reduces sheering. Check chafe where the line passes through the fairlead: wrap it with chafe tape or a short length of hose.

Anchoring Under Sail and in Awkward Conditions

Day Skipper candidates are mainly assessed anchoring under power, but you should know the principles of anchoring under sail, which is needed if the engine fails.

1. Prepare the anchor and chain as before, and brief the crew. Decide on the final approach with the headsail furled or dropped and the mainsail still set.
2. Sail up to the spot on a close reach or head to wind, using the main to control speed (ease to slow down, sheet in to speed up).
3. When the boat stops over the spot, drop the mainsail or let it flap, and lower the anchor.
4. As she falls back, let the chain out steadily; the wind blowing on the hull and rig provides the astern movement.
5. Snub and prove the set by watching transits. Without the engine, you cannot power-test, so allow extra scope and keep a watch.

In a strong tidal stream, anchor into the stream if wind is light, or into the wind if the wind dominates. If the anchorage is narrow, pick a point where you can drop back on a clear line.

Second Anchors, Kedges and Fore-and-aft Anchoring

The kedge

A kedge is a second, lighter anchor kept ready for warping the boat off, for a second anchor in bad weather, or as a stern anchor. The usual rode is 5 to 10 m of chain plus 40 to 50 m of nylon. A Fortress or Danforth type is often chosen for its holding power in relation to weight, and it also stows flat.

Using two anchors

• Bahamian moor: two anchors set in opposite directions, with the boat held between them at the point where the rodes join. The boat swings on a very small circle at the turn of the tide. It is used in strong tidal rivers, but it risks the two rodes wrapping if the boat swings a lot.
• Veer-and-hold, or tandem: a second anchor attached to the first, or set at a small angle, to increase holding in storm conditions.
• Fore-and-aft: an anchor off the bow and another from the stern, for a narrow anchorage or to keep the bow to the swell. Keep the rodes taut and clear of one another.

Using two anchors increases the complexity and the risk of tangles, and the boat is harder to weigh in a hurry. It is a tool for a particular problem, not a default.

Anchoring Etiquette and Environment

• Anchor at a reasonable distance from others. A good guide is that your swinging circle should not overlap anyone else's, with extra distance if their rode is longer than yours.
• Do not run the engine, generator or loud music late at night. Sound travels far across water.
• Show an anchor light every night; a small LED masthead light is cheap and effective.
• Do not dump rubbish or waste, including water from a holding tank, in the anchorage.
• Avoid seagrass beds, coral and marked conservation zones. In the UK, check for voluntary no-anchor zones or advanced mooring buoys, which are often provided to protect a habitat.
• Be considerate when leaving, so that your engine and chain noise do not wake others at dawn.

Anchoring in Strong or Changing Winds

If the forecast is for increasing wind, make these changes before it arrives rather than after:

1. Let out more scope: 7 to 1 or more on chain if there is room.
2. Use a snubber or bridle to reduce snatching.
3. Consider a second anchor on a separate rode, set about 30 to 45 degrees from the first, and let out the chain on both.
4. Reduce windage: take down the spray hood, lash the boom, remove any canvas that catches the wind, and secure a dinghy on the foredeck.
5. Start the engine and be ready to motor to ease the strain in a gust.
6. Set a watch rota and move the anchor alarm radius to match the new scope.
7. Make sure the crew know the plan to leave: where you would go, and how you would weigh in the dark.

A veering or backing wind, for example after a front passes, may change the anchorage from sheltered to exposed within minutes. Look at the forecast time of the wind shift and decide in advance whether the anchorage remains tenable.

Anchor Alarms: Setting Them Properly

A GPS anchor alarm is a good aid but is no substitute for a person. To set one:

• Mark the anchor position, not the boat's position. If the boat is at the end of the rode when you set the alarm, offset the centre or add the scope to the radius.
• The alarm radius equals the rode out plus the boat's length plus a margin of 10 to 20 percent for GPS error. With 40 m of chain on a 10 m yacht the radius should be about 55 to 60 m.
• Test the alarm by listening for it. Check the volume, and that it will wake the crew in the cabin.
• Remember GPS error: a modern receiver is accurate to a few metres, but it wanders, so too small a radius creates false alarms and the crew then ignore it.
• Back up the alarm with a depth alarm (a shallow alarm at your minimum depth) and a bearing check.

Second Worked Example: Anchoring Under Power with a Crew Briefing

You are skipper of a 9.5 m sloop with two crew, entering a bay with a charted depth of 4.0 m in sand, HW at 1400 height 3.8 m, LW at 2030 height 0.7 m. It is 1300, tide rising, and the forecast is south 3 to 4. The boat draws 1.6 m and the bow roller is 0.9 m above the water. You plan to stay until 1800 only, then leave.

Depth to plan for: highest tide during the stay is at 1400, 3.8 m. Charted depth 4.0 + 3.8 + 0.9 = 8.7 m. Chain at 5 to 1 for a four-hour afternoon stay in moderate wind: 5 x 8.7 = 43.5 m, say 45 m of chain. If you use a rope rode with 10 m of chain, you would let out 6 x 8.7 = 52 m of rode.

Minimum depth: the tide at 1800 is about 1.8 m, so the depth is 4.0 + 1.8 = 5.8 m: plenty of water. Even at LW the depth would be 4.7 m, leaving 3.1 m under the keel.

Crew briefing before the approach. "I will motor in from the north on a heading of about 190, and stop over the spot marked on the chart. Jo, you are on the foredeck. Wear shoes and gloves. We will lower the anchor to the seabed under power from the windlass, then pay out 45 m as we drift back. The chain is marked at 10 m with red, 20 m with white, 30 m blue and 40 m yellow. Use these signals: pointing for direction of the chain, hand up for stop, circling hand for more chain, thumbs up for anchor holding. Sam, you will watch the transit abeam and call out if the boat drags. I will use 1500 rpm astern to set the anchor."

Result. At 45 m the boat is at the planned swinging radius of 55 m, clear of the shoal 80 m away and of the nearest moored boat at 70 m. The power test shows no movement of the transit. The boat lies quietly. You set the alarm radius to 60 m centred on the anchor position, hoist the ball, write the position, depths and bearings in the log, and have a swim.

Exam and Practical Tips

• The instructor will watch your briefing as much as your boat handling. Brief before you approach, not during.
• Give a calculation with real numbers: depth plus tide plus roller height, multiplied by the right scope.
• Say that you will check the swinging circle at low water and after a tide turn.
• Prove the set: transit, engine astern and a hand on the chain.
• When weighing, talk through the boat handling: motor up slowly, take in the slack, signal when up and down, signal when the anchor is clear of the bottom.
• When picking up a mooring, state the heading you will use and why.

Worked Example

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The plan

You plan to anchor overnight in a sheltered bay. Your yacht is 10 m long, draws 1.8 m, has all-chain rode with 50 m of chain, and a bow roller 1 m above the water.

Tidal data (standard port, applicable to the bay):

The forecast is west 4, increasing 5 overnight. You arrive at 1600 and plan to leave at 0800. The chosen spot has a charted depth of 2.6 m in mud, and the chart shows a 1.2 m patch about 45 m to the east.

Step 1: maximum depth. Highest tide during your stay: 4.4 m (0530). Depth at that HW = 2.6 + 4.4 = 7.0 m. Plus bow roller 1 m = 8.0 m.

Step 2: chain needed. Minimum 4 x 8.0 = 32 m. With Force 5 forecast and an overnight stay, use about 5 x = 40 m. You have 50 m, so 40 m is fine.

Step 3: minimum depth. Lowest tide: 0.9 m (2310). Depth at the anchor spot = 2.6 + 0.9 = 3.5 m. Draught 1.8 m, so 1.7 m under the keel. Good.

Step 4: swinging circle. Radius = 40 m chain + 10 m boat = 50 m. The 1.2 m patch is 45 m away, inside the circle. At LW the depth there is 1.2 + 0.9 = 2.1 m: only 0.3 m under the keel, and less in any swell. With a westerly wind you will normally lie to the east of the anchor, i.e. towards the shallow patch.

Step 5: decision. Move the anchoring spot at least 30 m further west, into a charted 3.0 m, so the shallow patch is more than 60 m from the anchor and outside the circle. Re-check the swinging circle for other boats and moorings.

Step 6: on arrival at 1600 (rising tide, about 3.9 m height). Actual depth about 2.9 (new spot 3.0) + 3.9 = 6.9 m. Do not reduce the chain because it "only" looks 7 m deep now: you planned for 8 m including the roller at the highest tide. Let out 40 m, snub, power test astern, set the GPS alarm with a radius of about 60 m, hoist the anchor ball and switch on the anchor light at dusk.

Common Mistakes

The diagram lists the most common anchoring errors.

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• Too little scope is the commonest cause of dragging. When in doubt, let out more.
• Using arrival depth instead of the maximum depth during the stay, and forgetting the bow roller height.
• Dropping the chain in a heap on top of the anchor.
• Not proving the set with a power test and transit.
• Ignoring the swinging circle at low water and after the tide turns.
• Anchoring too close to other boats, or on a different type of rode, so you swing into them.
• No anchor light or ball. It is a legal requirement and other boats need to know you are not under way.
• Leaving the strain on the windlass instead of a snubber or cleat.
• Using the windlass to pull the boat forward when weighing anchor.
• Waiting to see if dragging stops. Act at once.

Summary

• Choose an anchorage for shelter now and later, good holding (mud, clay, sand), enough depth at LW and room to swing.
• Know your anchor type and its strengths; size it generously.
• Scope: at least 4 x depth for chain, 6 x for chain and rope; more overnight or in wind.
• Calculate depth at the highest tide during your stay, plus bow roller height. Check depth at LW across the whole swinging circle.
• Brief the crew and agree hand signals before anchoring or weighing.
• Approach slowly into the stronger of wind and tide, lower under control, lay the chain out, snub and power test.
• Show a black ball by day and an all-round white light by night.
• Keep an anchor watch with GPS alarm, transits and depth; if dragging, act at once.
• Weigh by motoring gently up to the anchor; break it out when up and down; stow securely.
• Pick up moorings on the same heading as moored boats lie; use proper lines and slip lines to leave.

Check Your Understanding

1. Rank these seabeds for holding: rock, mud, weed, sand.

Answer: Mud (best), sand, then weed and rock (poor). Firm sand can be as good as mud.

1. Charted depth 3.0 m, maximum height of tide during your stay 4.5 m, bow roller 1.0 m. How much chain is the RYA minimum?

Answer: Depth for planning = 3.0 + 4.5 + 1.0 = 8.5 m. 4 x 8.5 = 34 m of chain (6 x = 51 m if chain and rope).

1. Why should you not simply drop the anchor and chain in one go?

Answer: The chain piles on top of the anchor and can foul it, so it does not set. Lower it to the bottom, then lay the chain out as the boat drops back.

1. How do you confirm the anchor is holding?

Answer: With full scope out, go astern gradually to moderate revs and watch a transit abeam and feel the chain. If the transit stays steady and there is no vibration, it is holding.

1. What is the radius of your swinging circle with 35 m of chain out on an 11 m yacht?

Answer: About 46 m (rode plus boat length).

1. What signals must a yacht at anchor show by day and by night?

Answer: By day, one black ball forward. By night, an all-round white light forward.

1. Your anchor alarm sounds at 0200 and the bearings ashore are changing steadily. What do you do?

Answer: You are dragging. Call the crew, start the engine (checking no lines are in the water), motor up to take the load off, and either let out more chain or weigh anchor and re-anchor or leave. Do not wait to see if it stops.

1. How should the helm and bow crew work together when weighing anchor?

Answer: The bow crew points the direction of the chain and signals; the helm motors slowly up towards the anchor so the windlass only lifts the chain. When the chain is up and down, the anchor breaks out and the bow crew signals that it is off the bottom.

1. How can you free an anchor fouled on a rock or old chain?

Answer: Motor round it with a short chain to pull from different directions, or pull from the opposite side; if a trip line was rigged, pull the anchor out by its crown; as a last resort, buoy the chain and slip it.

1. How should you approach a mooring buoy?

Answer: Slowly, on the same heading as boats already moored, into the stronger of wind and tide, with the bow crew pointing to the buoy and signalling distance.

1. You expect the wind to increase to Force 6 overnight. List four changes you would make to your anchor arrangements before dark.

Answer: Let out more scope (7 to 1 on chain), fit a snubber or bridle, consider a second anchor, reduce windage, start a watch rota with the alarm radius reset, and plan an escape route.

1. How should the radius of a GPS anchor alarm be set?

Answer: About the rode let out plus the boat's length plus a 10 to 20 percent margin for GPS error, centred on the anchor position and not the boat's position when you set it.

1. Why is a snubber used with an all-chain rode?

Answer: It absorbs shock loads, stops the boat snatching and takes the load off the windlass and chain locker; the chain then hangs slack and keeps the pull on the anchor low.