An anchorage should provide:

1.    Shelter from all directions

A typical ‘perfect anchorage’ might be a horseshoe-shaped bay encircled by cliffs or hills, ensuring good shelter from all wind directions, unless it is blowing straight through the entrance which would drive in swell and make the bay extremely uncomfortable.

Be aware that wind often swings through 180 degrees during the night, when a strong sea breeze changes to a light land breeze.  Anchoring in the lee of high hills or mountains may appear to provide the best possible shelter, but not when a katabatic wind (from the Greek word katabatikos meaning ‘going downhill’) accelerates down the hillside at violent speed!

2.    Flat Water

Ideally, your anchorage should be as flat as a mill-pond.  Any swell will make it extremely uncomfortable.  If the boat starts rolling, things seldom get better.  Best advice is to move on as soon as possible to seek and alternative anchorage.  This may be caused by the wind swinging onshore.  However, swell is unpredictable and can roll in during the night if you are unlucky.  The best solution is departure at dawn.

3.    Good holding

Anchors are incredibly effective at holding a boat, but need a good holding.  The best surfaces are sand or mud, which allow the anchor to dig in deeply.  Rock and weed or shingle will provide a less secure holding.  Never drop an anchor on coral.

4.    Room to swing

Your boat should have room to swing through a 360 degree arc, without hitting anything under or on top of the water, including nearby boats.  All boats will swing as the wind or tide changes, though yachts and powercraft tend to swing at a different speed.  If there is insufficient space to swing through a wide arc or full circle, the solution may be to attach a stern line to the shore, which will hold the boat in a fixed direction.  This is useful when there is limited space in an anchorage and common practice in Baltic countries such as Sweden and Finland.  Remember though, if you are secured differently to the other vessels around you, your swing will be different to theirs.

5.    Tidal effects

If you anchor in a tidal area, you need to be sure there will be enough water under the keel at low tide.  The exception is if you wish to ‘dry out’ with a bilge keel yacht, lifting keel yacht or shallow draught catamaran.  Tidal flow may also affect where you can anchor in a river or estuary.  Every six hours, your boat will swing through 180 degrees as the tide changes.  An anchorage with the bows facing into the wind and tide should provide flat water and good shelter for the crew in the cockpit, but the boat may start to rock and the cockpit may get draughty when the wind blows against the tide.

“Some of my most enjoyable nights on the water have been at anchor with friends. The article is called a ‘perfect anchorage’, yet we all know it is unlikely to be absolutely perfect, however if you spend some time considering the points covered here before arriving at your anchorage and use a check list to select your spot it is likely to be an enjoyable stay with no unexpected surprises”, comments Vaughan Marsh, RYA Chief Instructor, Sail Cruising.

So remember; things to consider when choosing a good anchorage:

Shelter from the wind

The weather forecast in case the wind direction changes

The nature of the seabed shown on the chart. Mud and sand are better than rock or shingle

Space behind the boat

Whether there is enough room to swing when the tide turns

Check on the chart for a recommend anchorage

Look in the pilot book for advice or warnings

The boat must be outside any channel used by other boats, including if it swings

The depth of water.  It may be necessary to work out the minimum depth of water in which to anchor to be sure that the boat will not ground at low water

Once secure, monitor your yachts position in comparison to the other vessels and hazards including the depth for the duration of you stay

Extracts taken from RYA Day Skipper Handbook – Sail, by Sara Hopkinson and RYA Yacht Sailing Techniques, by Jeremy Evans.

via The perfect anchorage | InBrief | e-Newsletters | News & Events | RYA.