Anchors

Find out about anchors including how to choose the right anchor, selecting a site to anchor and retrieving the anchor. Anchor rules and regulations are also provided here.

  Who must carry one and how to choose

If you are operating in unprotected waters (outside the waters contained by any breakwater or in any lake, river or estuary other than the waters of Cambridge Gulf or Lake Argyle) you must carry an efficient anchor and line.

Choosing an anchor

The anchor must be of a type that will hold in all seabed conditions and with enough line to suit the depths in which you usually operate.

Most people choose one of the following high holding power designs:

Anchor designs

Name Design Positives Negatives
Danforth Danforth This is the most common type for trailer boats that do not stow the anchor below a bowsprit. It has excellent holding power in most bottoms, especially sand and is modest in price. None reported
Plough or Coastal Quick Release (CQR) Plough or Coastal Quick Release Its holding power is similar to the Danforth, but it has a better reputation for holding in mud. Also, it is better suited for self-stowing under a bowsprit. This is more expensive than the Danforth because of its more complex construction.
Bruce or spade Bruce or spade This is the best of all for bowsprit stowage and is gaining in popularity. For small boats, where the anchor is stowed within the vessel, it is very cumbersome.
Standard Stockless, Admiralty pattern Standard Stockless, Admiralty pattern The best anchor for piercing weed beds and it also works well in mud. Weight for weight it is one of the best all round anchors. The sailors cap badge anchor looks old fashioned. It can be inconvenient to stow.
Reef or grapnel Reef or grapnel Useful second anchor for rocky bottoms. It won't get stuck on rock; will straighten out under a heavy load and withdraw. Too specialised to be acceptable as a boats sole anchor.
Sea anchor or drogue Sea anchor or drogue Ideal for offshore boating; slows drift and keeps bow of boat facing wind and waves. None reported

  Anchor cables

There are 2 types of anchor cables:

  • All chain.
  • Rope with a piece of chain joining it to the anchor.

The chain is necessary because of its:

  • Weight.
  • Horizontal pull.
  • Shock absorbent ability.
  • Ability to reduce rope chafing.

The best anchor ropes are:

  • Nylon is very strong with lots of stretch.
  • Polyethylene silver line.

If the rope is nylon, you will need at least 2 metres of chain; other rope will need at least 3 metres.

Your anchor and cable should always be ready to run freely at a moments notice.

  Weather and selecting a site

Weather

Check both the existing and forecast weather before anchoring. This could influence whether you will use more cable, or even decide to move elsewhere. Strengthening winds blowing on shore (technically giving you a lee shore) should especially influence your decisions.

Selecting a site

  • If you have a choice of bottom in which to anchor (in other words it is not an emergency), sand is ideal, firm mud next best. It is better not to anchor on a weed bed both for environmental reasons, and because most anchors find it difficult to grip.
  • Check that when have let your cable out you will have enough room to swing to wind or tide without hitting the bottom or other vessels.
  • If you are in a tidal area, ensure that you will have enough depth at low water.

  Preparing to anchor

Picking a spot to anchor

Having picked the spot to anchor and determined that you have enough cable, at low speed turn your boat to face the wind (on a low wind day face the current, if any). Put the motor in neutral, then in reverse for long enough to get the boat moving astern.

Lowering the anchor

Lower the anchor (do not throw it) to the bottom, and pay out cable as the boat moves astern with the wind.

Setting the anchor

When the rope/cable is fully out, secure the cable and give the engine a short burst in reverse to ensure that the anchor has bedded in.

Ensuring enough rope/cable

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The critical element of anchoring is to have enough cable out (enough scope is the jargon).

The scope is the ratio of the length of cable used for the depth of water.

The absolute minimum is 3 times the depth of water, and 5 or 7 is better. Strong current or wind or a choppy sea puts more load on the cable and makes a bigger scope more desirable.

Recommended scope

Condition Scope
Calm 3:1
Fair 5:1
Moderate 7:1

Monitoring the anchor

Once the anchor has set and bedded in, you should take a few bearings or line up some objects (transits) to check that the anchor is not dragging.

If you notice that you are drifting off the bearing:

  • Place your hand on the cable and feel for any signs of the anchor bouncing along the bottom.
  • If the anchor is dragging and you have enough room, try paying out more cable. In most cases, decreasing the angle between the anchor and the boat (for example: letting out more line) will be all that is required to get the anchor to bite.

Securing the anchor line

The very end of the anchor cable should be secured within the vessel to prevent loss of the anchor. If not using the whole cable, the chosen length should be secured to deck hardware.

  Retrieving the anchor

Don't overt exert yourself by pulling the boat up to the anchor: let the motor do the job while you, or your winch, retrieve the cable. You may need to indicate to the driver which way to steer.

To prevent snagging when the cable is vertical, it may be necessary to take a turn of it around the bitts and let the engine power break the anchor out of the bottom.

If the anchor will not break out, slacken the cable, back off, and approach the anchor from different directions.

  Maintenance

Your anchor and its cable (rope and chain) are part of your safety gear and should be:

  • Ready to run at any time and not coiled, make sure that when the anchor is dropped it will be taking rope from the top of the coil, avoiding kinks and tangles.
  • Coiled clockwise into the cable well or the dedicated box, ready for instant use without kinks.
  • Secured separately to prevent the anchor passing through a loop and tangling.

  Rules and regulations

Channels and leads

Anchoring is prohibited in any channel, fairway, passage or leading lines unless you are in distress or obtain the permission of the Department of Transport.

Submarine cables

Anchoring is prohibited in the vicinity of telephone, submarine and power cables laid on the seabed. These anchoring prohibited areas are marked on nautical charts and must be complied with.

Mooring areas

Anchoring is not recommended in mooring areas. You could foul your anchor on the moorings and, because the spacing of moorings is usually only a little more than needed for the vessels on them to swing clear of each other, you would be likely to hit other boats.

Ports

Ports have individual rules for small craft using their waters. The overwhelming intent is to avoid any conflict with large commercial vessels, so ensure that you do not anchor anywhere near where these vessels pass.

Image of boat anchor

 

Page last updated: Fri Feb 9 2018 2:45:51 PM