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Anchor Buoy

ANCHORING

PARTS OF AN ANCHOR

1. Anchor Ring       5. Arm
2. Stock                 6. Fluke
3. Shank                7. Bill
4. Crown

COMMON ANCHORS

KEDGE / ADMIRALITY
Good holding power - but not for use in shallow water

DANFORTH
Good holding, Easy deck stowage. Better suited for small craft

GRAPNEL
For reef use. Not suitable for general purpose in mud or sand

BRUCE
Very efficient but difficult to stow on deck

CQR (PLOUGH)
Good holding power but difficult to stow on deck without bow rollers

STOCKLESS
Average holding power but easier stowage

ANCHOR SIZES

Anchor Topics

The anchor sizes listed below are indicative only. Depending on the weight and vertical footprint of the vessel larger sizes than those shown may be required

CQR (PLOUGH)
WEIGHT (Kg)	BOAT LENGTH (M)
4.5	5
16.8	7
9.1	8
12.3	9
13.6	10
15.9	11
20.5	13
27.3	15

DANFORTH (SAND)
WEIGHT (Kg)	BOAT LENGTH (M)
1.5	3
2.7	5
3.6	6
4.5	7
5.9	8
7.3	8.5
10	9
16	10

BRUCE
WEIGHT (Kg)	BOAT LENGTH (M)
3.4	8.5
4.5	10
6.8	12
9.1	14
13.6	17

ANCHOR CABLE (RODE)

Anchor Topics

      Recommended specifications for anchoring gear will vary - but not by much. When in doubt use stronger and / or longer rope and chain. In open or less protected waters several anchors must be carried.
        BEST SYSTEM - Short link chain
       SECOND PREFERENCE - Rope with a length of chain pennant

Rope Properties
Nylon best
Larger diameter Silver Rope
Non floating

Chain Pennant
Reduces chafing on bottom
Reduces shock load
Increases anchor holding power

Connection
Hard eye in the rope
Moused (Lock-wired) shackles

BOAT LENGTH	ANCHOR ROPE		CHAIN PENNANT
	SIZE	LENGTH	SIZE	LENGTH
Up to 5 M	8 mm	50-70 M	6 mm	3 M
5-8 M	10 mm	75-100 M	6 mm	6 M
8-12 M	12 mm	100-125 M	6-8 mm	10 M

ANCHOR SCOPE

Anchor Topics

SEA CONDITIONS	ANCHOR CABLE	SCOPE
Favourable	Chain	3 : 1
Average	Chain	5 : 1
Rough	Chain	7 : 1

Favourable	Rope	5 : 1 #
Average	Rope	8 : 1 #
Rough	Rope	10 : 1#

# The figures for Rope assume that a chain pennant of sufficient length is fitted (See table above)

ANCHOR BUOY

Anchor Topics

An anchor buoy consists of a float and line attached to the crown of the anchor. The float must be small enough so that it exerts almost no pull on the anchor and the line long enough to allow for tidal changes - but not so long that it does not float nearly on top of the anchor. The are two reasons for having an anchor buoy. It is useful to indicate the actual position of the anchor - especially in crowded anchorages. If the line is strong enough it can be used to help retrieve an anchor fouled in rocks or coral

ANCHOR MOORING

Anchor Topics

A mooring system deploying and using two anchors as shown in the diagrams has several advantages - swing room is considerably less and by using different types of anchors extra security is gained. Note that the swivel is essential to avoid twists and consequent fouling of the separate anchor cables. The swivel must be strong and of good quality.

ANCHORING HINTS

Anchor Topics

#      The final dropping site should be chosen based on an assessment and knowledge of the following - Holding ground quality, Shelter from the weather, Swinging room, Tidal range, and Current flow.
#      Make the final approach into wind or current - whichever is likely to have the greatest effect.
#      Ensure the anchor and cable are ready for letting go - making sure the tale of the cable is secured on board.
#      Have the vessel going slowly astern as the anchor is let go.
#      When the required scope is run out secure the cable and take bearings - especially abeam, to confirm that the anchor is holding. Do not stop the engine until anchor holding is confirmed.
#      Set anchor alarms (GPS or Depth Sounder) where possible.
#      Allocate an anchor watch - especially in areas of strong tidal current changes or significant wind changes.
#      When in the one spot for a long time take in or let out a little cable to avoid damage at contact areas.
#      When in deep water control the run out speed of the cable - at least until the anchor is near the bottom.
#      Avoid anchoring near a shelf - to avoid the anchor coming off the bottom if dragged into the deep water.
#      When recovering an anchor wash of mud before the chain / rope comes on board. To do this easily mount some stiff scrubbing brushes on the inside of a piece of V-shaped rigid metal (Aluminium or Stainless Steel best). Then secure the point of the V to a rigid pole of suitable length so that the brushes can be run up & down the cable at water level during the retrieval. A safety strap on the end of the pole is also useful.
#      If the anchor is difficult to break out motor gently over the anchor and continue ahead.

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