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Anchoring skills: expert advice to improve your knowledge

YM instructor Rachael Sprot steps aboard to help. This month Sophia Lagus and crew want to… anchor off the beaten track with confidence and improve their anchoring skills

Anchoring is one of the greatest joys of sailing, yet for many people the sound of the chain rattling over the bow-roller is the start of an anxious night. Will it hold? What if the wind shifts? Will you swing into something? There are many questions and many anchoring skills to master for the uninitiated.

If you can master the art of anchoring you’ll enjoy a huge sense of freedom and independence, dropping the hook miles from the nearest settlement. I joined Sophia Lagus in Dartmouth on board her Malo 46 Wimsey to help build her confidence to leave the pontoons behind.

Diagnosis: Sophia and her crew are planning to cruise the west coast of Ireland in her Malo 46 Wimsey. Although they’ve got lots of sailing experience, they tend to marina hop and don’t often spend time at anchor. But there aren’t many marinas where they’re heading, so they need to put the lines and fenders away and become more familiar with their ground tackle.

Like most seemingly simple tasks, anchoring takes planning. New generation anchors offer much better holding power-to-weight ratios. The bow roller needs to be correctly sized for your anchor, ideally with a chain groove to prevent twists.

It’s easy to get confused by tidal heights and chain scopes, but the sums are simple once you’ve done them a few times. Photo: Nic Compton

Anchor chain is an important part of the equation. It will usually be 3-4 times heavier than the anchor itself, adding valuable weight and helping achieve good scope. A length of 40-60m facilitates anchoring in depths of 10-15m, adequate for most of the UK.

Warp should be octoplait with eight strands. This has less twist than three strand, and can be spliced through the chain to give a strong, seamless connection. Wimsey has a stainless Bruce anchor, which should give good holding in mud, a swivel, and 60m of 10mm chain.

Anchoring skills – choosing an anchorage

Identifying a good anchorage is half the battle. The better-known spots are in the pilot guides, but you needn’t limit yourself to those. Choosing your own anchorage is simple when you know what to look for. Shelter For open anchorages, an offshore breeze for the duration of the stay is essential, as well as protection from the sea and swell.

Hallsands looking SW with a tidal surge coming around Start Point. Photo: Nic Compton

Check the forecast for wind shifts which could turn a secluded cove into a dangerous lee shore. Swell is harder to predict.

When I joined Wimsey we had a prolonged period of easterlies. We were keen to explore the coastline between Salcombe and Plymouth which has lovely anchorages such as Bigbury Bay and Hope Cove. However, despite the offshore wind, swell from distant Atlantic depressions crept up the English Channel and made the area untenable.

We had a quick coffee stop in Hope Cove and moved off to Salcombe. When the wind swung west again the sandy bays between Start Point and Dartmouth became accessible. We anchored off Hallsands but it had a tidal surge on the flood from its proximity to Start Point.

The character of tidal anchorages can change through the cycle. As well as the change in stream, the shelter varies as things like rocky ledges, which can form natural breakwaters, cover and uncover.

Nature of the seabed

One if the key anchoring skills for cruisers is understanding what lies beneath the surface. Sand and mud give the best holding as long as they aren’t too soft. Weed and rock should be avoided.

Rachael helps Sophia and crew calculate their options for anchoring. Photo: Nic Compton

The chart gives some indication of the seabed, but there are other clues. The visible coastline can indicate what’s going on under the surface. Rocky outcrops on shore may extend to seaward, as will the stretch of sand between them, so try to position yourself in that. Sand reflects more light than kelp or rock so drop the anchor into paler patches.

The satellite view on Google Maps is invaluable. Save screenshots to your phone prior to departure. Smooth contours suggest sand, and rocky bottoms are more irregular.

Depth

You need to consider both high and low water depths. You don’t want to ground at low water, but anchor too deep and you won’t have enough scope at high water.

The length of anchor chain and warp limits the depth you can successfully anchor in. A 4:1 ratio gives a decent scope on chain, and you need 6:1 for warp. It’s imperative to know the height of tide when you arrive so that you can factor the rise and fall of tide into your choice of spot.

The minimum depth to anchor is: Draught + Clearance + Fall of tide. The clearance you choose depends on the conditions. In soft mud 0.5m may be adequate, but on a rocky bottom you’ll need more.

Hope Cove with a southwesterly swell coming around Bolt Tail. Photo: Nic Compton

We approached the anchorage in the River Dart just south of the Anchor stone near Dittisham. Wimsey has a 2.1m draught and Sophia chose a 1m safety clearance. Using the tidal curve we calculated that the height of tide was 3.9m. We were an hour after high water, and the tide would fall to 0.2m above CD giving a fall of tide of 3.7m.

Draught: 2.1m + Clearance: 1m + Fall of tide: 3.7m = 6.8m minimum anchoring depth

To calculate how much chain to use, find the maximum expected depth. If you will stay over high tide (4.3m for us), that will be: Depth gain (3.9m to 4.3m): 0.4m + Current depth: 6.8m = 7.2m Max depth x Scope of 4:1 = 28m of chain

Swinging room

Finally, you’ll need to consider swinging room. You can’t do this until you know roughly what depth you’ll have, and how much chain to lay out. In our example we would need 29m chain.

As the tide ebbed around Anchor Stone, Wimsey swung in the eddies. Photo: Nic Compton

The radius of the swinging circle is marginally less than the length of chain that’s out, 28m, plus the length of the boat. So 28m chain plus 15m LOA = 43m radius from the anchor point.

Most of the time the chain doesn’t pull tight. Some of the chain sits on the seabed creating friction and dampening the vessel’s motion. If it does pull taut in
strong conditions this tends to be in one or two directions. It would be very unusual to do a full orbit of your anchor at maximum extension.

Check your zoom level to get a sense of scale. Many chartplotters now also show current tidal height for your location. Photo: Nic Compton

Scale

Understanding scale is helpful when predicting how confined an anchorage is. Zooming in on digital charts can be misleading so measure the navigable dimensions. As a guide, a cable (182m, 200 yards, 0.1 mile) is a comfortable width, allowing swinging room for several yachts.

Try to anchor amidst similar vessels that will behave like yours. Photo: Nic Compton

Anchoring skills – approach

Identified any hazards and made a plan to avoid them. The anchorage south of the Anchor Stone is close to Parson’s Mud, which is steep-sided. We explored its limits gingerly before dropping the anchor in deeper water.

The nuances of depth often vary from those on the chart, so ‘sounding in’ is a necessary part of the reconnaissance. Use the track feature on your chart plotter or phone to record the survey. You can then monitor the vessel position against the limits of the track throughout the stay.

When the wind picks up in the middle of the night it’s handy to be able to check that you’re still on track, without leaving your bunk. You’ll need to ensure the track interval frequency is set to high. Most phone apps naturally have good resolution, but some plotters only record a position every 2-3 minutes so you could miss some details of your survey.

Other vessels

Position yourself carefully relative to other vessels. Visualise their anchor location by looking at their scope and assessing the conditions: are they sitting well back or right on top of it?

You’ll lie three different ways in a tidal cycle: to the flood, the ebb and to the wind – your anchor position needs to take all three into account. Photo: Nic Compton

Dropping your anchor astern and slightly to one side of other vessels avoids an entanglement. If the crew are present, find out how much chain they’ve laid out to work out their swinging circle.

Different vessels have different swinging characteristics. Motorboats and lightweight yachts are wind-sensitive. Heavy displacement, long-keeled yachts lie more to the tide. Yachts on warp have larger swinging circles and more erratic motion than those on a chain.

Try to anchor amongst similar vessels which will behave like yours.

Dropping the anchor

Before dropping, always check the connection between your chain and anchor: shackles must be properly seized. Galvanised shackles bind better than stainless.

Having taken care to choose the right spot, you need to release the anchor quickly. Prior to arrival, lower it over the bow roller so that it will run instantly when released.

When it comes to dropping anchor, release the clutch and let gravity do the work. Photo: Nic Compton

Bring the boat to a stop into the wind or tide and tell the foredeck crew how much chain to let out. Paying out the chain Release the clutch and let gravity do the work. This is faster than lowering on the windlass so the anchor will land exactly where you want it.

The crew must always stand clear of the chain.

Paying out the chain can be done with more control: let out two thirds of the chain quite fast – you don’t want to tension the chain until there’s sufficient scope for the anchor to bite – then control the rest on the clutch to prevent the bow blowing off too much.

Chain markings make it easier to see how much chain has been let out. Photo: Nic Compton

Chain Markers

Chain markings make it easier to see how much chain has been let out. Plastic inserts are the best, although coloured cable ties or whipping cord also work well. Paint isn’t terribly durable unless the surface is very well prepped. Keep the colour coding simple with big blocks of colour to make it easy to see when the chain flies out.

Foredeck crew should indicate which way the chain lies to the helm. Photo: Nic Compton

Bedding in and Holding

Once the chain is out the boat should swing to the anchor and you now need to establish whether it’s holding. Use SOG transits with objects on the beam or compass bearings to observe your position and apply slow astern power. The chain should come taut and the boat should feel tethered by the bow. The chain should feel taut if you place your foot on it, with no vibrations.

Give the engine a bit more power, to help it bed in and simulate strong winds. ‘Good night sleep revs’ are essential for peace of mind. If the chain slackens or the bow falls off it’s probably dragging, so reduce the revs and add another 10m of chain. Hopefully more scope will give the anchor a better chance of holding.

Occasionally the anchor will drag a few metres until it’s found a patch of good holding but avoid doing it for too long as it damages the bottom.

Re-setting

Sometimes the only option is to raise it and try a different spot. Well-used areas can be badly scoured with little mud remaining over the harder substrate, especially at the end of the season.

Snubbers

Once set you should relieve the strain on the windlass. You can transfer the load to the bow cleats using a strong warp with a rolling hitch or by attaching a chain hook and bridle.

Snubbers are a controversial topic. You need a long length of warp to introduce enough stretch to soften the load on deck fittings. This can be by running the lines of a bridle to cockpit winches. In most conditions snatching is reduced by the catenary effect of the chain if you’ve got enough scope. Some people don’t like the noise of the chain, but I like having it as part of my alert system and keep an ear open for it overnight.

Don’t forget the anchor ball and anchor light. Lashing the wheel amidships will help minimise yawing.

Position monitoring

As a minimum you need to make a note of the depth and some visual markers once you’ve settled in position. With a steady offshore breeze and good holding this may be enough, just check your position at dusk and get a good night’s sleep. There are times when more active monitoring is required, though, such as in strong or changeable conditions or with limited swinging room.

A rolling hitch will secure your snubber if you don’t have a hook. Photo: Nic Compton

You don’t need to stay up all night yourself, you can set an anchor alarm with a drag radius on your chart plotter or app, or ask the crew to pop their heads out once. A shallow depth alarm on the instruments also gives peace of mind.

If you’re worried about the change of tide, waking up for slack water is more efficient than spending all night worrying about it. At the Anchor Stone we slewed around as the tide eddied downstream of the rocky obstruction, sometimes facing 90° to the river. Despite its namesake, it isn’t a terribly good anchorage for this reason.

Conditions would be easier at Neaps or on the flood when the stream is weaker and isn’t interrupted by the stone. It would be best to anchor in good time before spending a night there. In some places you need to see how the boat sits at all states of the tide before clocking off.

Let the skipper know once the anchor is clear of the water. Photo: Nic Compton

Anchoring skills – retrieving the anchor

To retrieve the anchor you need to motor the boat towards it, with guidance from the foredeck crew. You want the chain more or less vertical to make life easy for the windlass. Keep a careful eye on the gypsy and hawse pipe for chain jams, a link can get caught, seizing the windlass. A well-set anchor may need ‘breaking out’.

With as short a chain as possible, drive forwards over the anchor to pull it from the opposite direction. If the anchor is totally stuck you may have to buoy it
and return in better conditions: undo the bitter end from the chain locker and tie a fender onto it.

Once the anchor’s on the surface you can start driving slowly into safe water whilst it’s being stowed. A muddy anchor can be gently towed at surface level for cleaning as long as it keeps clear of the hull.

Once home, the anchor should be lashed or secured with a pin.

Flaking the chain

Wimsey had a big chain locker directly under the anchor and the chain stowed away in this space very well. However, not all boats are so well-designed. If you have problems dropping the anchor it’s likely that the chain has capsized inside. However, sticking to a routine of flaking your chain should solve the problem.

Use a stick to deflect the chain from side to side, keeping your hands clear in case the chain runs out.

A box or bag can help organise the chain on deck. Photo: Nic Compton

Setting a second anchor

To rehearse setting the kedge we tried a different anchorage further up the river in a pool near Higher Gurrow point.

This was much shallower so we didn’t need as much chain but the channel was narrow here and we wanted to keep clear of the Totnes ferries.

A second anchor is useful where swinging room is restricted, to keep the boat head to the swell in a rolly anchorage or to stop the boat yawing about. A kedge can be rigged from the bow (Bahamian moor) or the stern depending on what suits the vessel and conditions.

Flake the chain, and then the warp, into the dinghy. Photo: Nic Compton

We took the kedge astern to keep Wimsey truly fore and aft on the edge of the channel. If you’re using it to take the full weight of the vessel, which we would have done in this instance when the tide reversed, then it needs to be as well set as your main anchor and with good holding power. It’s acting as the primary anchor at this point and you won’t get good results if the anchor is under-sized or if there’s little or no chain on it.

Wimsey’s kedge is a 20kg Danforth anchor with 20m of chain and 20m of warp, so it isn’t as good as the main anchor and we wouldn’t have relied on
it in strong conditions.

Lower the anchor, and then the chain from the dinghy. Photo: Nic Compton

Setting a kedge from the dinghy

  • Set the main anchor.
  • Attach a buoyed trip line to the kedge, long enough to be afloat at high water, but short enough to stay close to the anchor.
  • Attach enough warp to get the anchor into the position you want. The dinghy will struggle to reverse against the weight of heavy chain, so use a long line to allow the dinghy to drop back. You may need to bend on additional line temporarily in order to achieve this.
  • Flake the warp on the transom and attach one end to a cleat or winch.
  • Flake the chain into the bow of the dinghy with the anchor on top.
  • Make sure the boat is sitting well back on her main anchor. Leave the engine in tick-over astern if the conditions don’t do this for you.
  • Drive the dinghy astern until you’ve reached the position for the kedge. The warp should run freely from the transom.
  • Drop the anchor over the side of the dinghy and feed the chain over afterwards.
  • Take up on the warp in the cockpit and make fast – there should be plenty of scope.

Take up on the kedge so the yacht is roughly equally distant between the two anchors. Photo: Nic Compton

Setting the kedge without a dinghy

If the anchor chain is long enough, you can deploy the kedge without a dinghy:

  • Flake the kedge and chain on the transom of the yacht, with the anchor end up. Attach the bitter end to the boat.
  • Ease out an extra 20-40m of chain on the bow anchor and reverse the boat.
  • Drop the kedge and pay out the chain.
  • Take up on the main anchor until you’re back in the original position.

The dinghy crew approach the buoyed trip line to recover the kedge anchor. Photo: Nic Compton

Bahamian Moor Variation

The disadvantage of a fore and aft configuration is that if conditions change and the boat lies beam on to the wind, there will be a big load on both anchors. Anchoring to a bow anchor works well because the boat can move with the elements. If you restrict the boat, the risk of dragging increases.

The Bahamian moor allows the boat to swing freely whilst still tethering it into a single position.

  • Deploy the first anchor and drop right back on it.
  • Deploy the second anchor immediately down tide, from the dinghy or transom.
  • Lead the kedge to the bow and take up on the main anchor to centre the boat.
  • You can join the chains together before lowering another few metres to keep the lines clear of the keel. Running the kedge line through a snap block will allow you to tension the anchors against each other.

The drawback of the Bahamian moor is that there’s the potential for the yacht to turn 360°, twisting the anchor chains around each other. If this happens, you’ll need to undo one of them and unwind the chain.

Practise anchoring regularly to give you confidence for more remote overnight stops. Photo: Nic Compton

Retrieving a second anchor

If the dinghy crew haven’t mutinied yet, they can use the trip line to pull it up. This is hard on boats over 40ft due to the weight. Shaun and Debbie managed this on Wimsey, but only just.

Alternatively, buoy the bitter end of the kedge anchor chain and release it. Take up the main anchor. Return to the kedge and haul it up over a second bow roller, using the windlass if possible (you’ll have to take the main anchor chain off the gypsy).

Trip lines

I’ve never liked trip lines and only use them on the kedge. In my experience they wind themselves around the chain causing more problems. However, on rocky bottoms or in the vicinity of coral, it can be worth using one.

A fender on a line slightly longer than the maximum expected depth will keep the buoy above the anchor. Don’t use floating line as this could foul your prop.


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