Cable. The total length of anchor chain or rope carried by a vessel, and will be determined by the vessel size and weight. Not to be confused with a 'cable length' which is 0.1 of a nautical mile or approx. 185 m.
Rode. The amount of anchor cable (chain or rope) payed out. Often incorrectly called the warp.
Pennant. The length of chafing chain fitted between the anchor and a rope anchor cable.
Scope. The ratio of length of rode to depth of water.
Catenary. The sag of the rode. Determines the degree of horizontal pull on the anchor.
Kedge. To move the vessel position by hauling in on/relocating the anchor without use of engine power.
|There are two ways that anchors achieve their holding ability - by burying e.g. Danforth, Plow, and Bruce, or by hooking - e.g. Fisherman, Grapnel, or Bruce. Different sea bottom conditions will suit one type over another. |
Voyaging vessels should have a primary anchor for general all purpose anchoring, a backup or spare to the primary, and an oversize anchor for storm conditions. Ideally, at least one would be a burying type, and one a hooking type. Good ground tackle is inexpensive insurance for any boat, and it will give you peace of mind. When anchoring in the lee of a reef at night, be prepared for unpredictable wind changes, which can be quite localised and severe.
With a burying type anchor, it is essential to have the correct scope ratio to suit depth of water and conditions. To ensure maximum burying effect, the pull on the anchor shank must be horizontal. If there is any pull in an upward direction, the anchor will not be fully effective. Therefore, the rode must be of sufficient length to create the correct catenary effect or sag.
When anchoring, head into the wind or current, which will assist the setting of the anchor. In reef situations, endeavour to set the anchor over an open sandy area to avoid fouling the rode on coral.
|Traditional. A popular all purpose affordable anchor with excellent holding power for its weight. It has changed little in design since Richard Danforth made it decades ago. The crown assembly should engage the T section flukes at 32°. Because the shank is hinged and the flukes fold flat, it has good stowage ability. The stronger high tensile version is a beneficial improvement. Most suitable for sand and mud.|
|Lightweight alloy. Compact, lightness, strength, and good holding ability were design parameters for this anchor type from Fortress Marine in the U.S. An extremely strong alloy is machined to allow interlocking, with no welds to weaken the metal. There is the option of a 32° shank/fluke angle for sand or a 45° angle for mud. They're a practical stern anchor, being non-magnetic and easier to handle than other anchor types.|
|Plow Traditional.The most popular anchor, and for good reason. The harder the pull, the more it digs in. Provides excellent holding power on a variety of seabeds, and the hinged shank resists breakouts, even in shifting winds. It is easy to break free during retrival, and stows well on bow rollers. Based on the original CQR type.|
|Plow Delta. Strong one piece manganese steel design, allows remote dropping and retrival with a power windlass. Shank profile and low centre of gravity assists self launching. Suitable for all bottoms.|
|Kedge. A heavy type. Works well on rock and weeds. Bites quickly. Awkward to stow. Exposed fluke can foul anchor rope on small vessels. The standard anchor for larger merchant ships is a combination of the Traditional and Kedge patterns.|
|Bruce. Heat treated cast steel design has no moving parts. Stowage may be difficult, but is a highly versatile anchor. The curved wingtips and point are configured so that pull on the rode automatically rolls the anchor to its optimum upright position when tide or wind change. Buries at rode angles up to 30°. Breaks free easily when recovering. Beware of cheap copies.|
|Grapnel (Reef). A handy anchor for light duties such as kedging or for temporary holding. Recovery can be awkward on a reef.|