CHOOSE AND USE THE RIGHT ANCHOR
Proper anchoring is one of the
least understood areas of seamanship. After all, how much could there be
to it? You just throw the anchor overboard, wait until it hits bottom and
tie it off, right?
Anyone who has spent enough time on private boats has seen the wide
variety of problems this kind of simplistic attitude can foster. Just like
anything else, proper boat anchoring requires the right equipment, careful
thought and practice. Considering the possible consequences of
insufficient anchoring (drifting ashore during the night, colliding with
other boats), it’s definitely worth the effort.
Choosing the Proper Equipment
The first step is selecting the proper ground tackle (the collective term
for anchor, line, chain, shackles and swivels) for your vessel and your
style of boating. No one anchor does everything perfectly. Each of the
popular styles has its own benefits and drawbacks, and each performs best
under certain conditions.
Most popular styles are variations of the Danforth, the CQR/Plow anchor
and the Bruce anchor. The Kedge anchor – its familiar shape recognizable
from insignias, tattoos and large ships – actually has limited
applications for West Coast recreational boats.
The Danforth – easily identified by its two long, sharp pivoting flukes
and long shank – is a good choice for many small to medium-sized boats.
It’s relatively light and easy to store. The Danforth also digs well into
sand and mud bottoms, yet releases easily when pulled from a different
direction. A round rod across the crown end prevents the anchor from
rotating on the bottom as the flukes bury themselves.
The Danforth’s flukes pivot so the shank can be pulled at a more vertical
angler, facilitating easier release. It’s ideal for fishing, which often
requires frequent pulling and re-setting of the anchor in order to move to
a new spot or reposition the boat. If you frequently overnight or travel
to unfamiliar waters, however, you may want to choose one of the other
styles, which hold better in changing conditions.
The CQR or plow anchor features a single plow-shaped fluke that pivots at
the end of the shank. This design works well on a variety of bottoms. The
shank pivots from side to side, while remaining parallel to the fluke (in
the opposite direction of the Danforth). this means the plow anchor can
remain buried during moderate changes in wind or current direction. The
design also allows for a relatively easy release when the anchor is pulled
The Bruce anchor was originally designed for offshore gas and oil drilling
rigs. The scaled down version of this design is gaining popularity with
boaters. This design allows this anchor to hold fast, (even if the
direction of pull changes 360 degrees), yet it still comes loose when
Be sure to select an anchoring system that matches your boat’s length,
displacement and windage, as well as the type of boating you do. Only
top-quality braided nylon anchor line should be used to ensure strength,
elasticity and durability. It’s also important that the size and length of
the anchor line is appropriate for your vessel and specific requirements.
Small to medium-sized boats should also use a section (approx. ¾ to one
boat length) of galvanized steel chain between the line and the anchor.
The weight of the chain lowers the angle of pull and helps the anchor set
more effectively. Large vessels equipped with power winches can use all
chain, but this adds considerably to weight and cost.
Setting the Anchor
Without a doubt, the most common mistake made when setting anchor is not
using sufficient scope. When this occurs, the anchor is much more likely
to drag, break free or get fouled. To get a solid hold and dig into the
bottom, you need to make the angle of pull as low as possible. The U.S.
Power Squadron Course Book uses this analogy: Bury a pickaxe into the soft
dirt. Lift up vertically on the handle, and it breaks free relatively
easy. Pull at an angle low to the ground, however, and pick actually digs
deeper in the soil.
This is the effect of scope – a number that denotes the ratio of anchor
line length to the depth of the water. To keep the angle of pull as low as
possible, it’s necessary to pay out a healthy amount of anchor line. A
scope of 5:1 is a good working minimum for normal conditions. If you are
anchoring in stormy weather, you should double this amount. What does this
mean in practical terms? For example, if you want to anchor in 20 feet of
water, you would first need to accurately gauge the speed and direction of
wind or current (whichever is stronger), then position your boat well
“uphill” from your desired position. Then the captain would use reverse
gear to “scope back” approximately 130 feet of anchor line. This accounts
for the 5:1 ratio, including an estimated distance of six feet between the
surface of the water and the anchor roller. Most dealers offer inexpensive
anchor line “marker tabs,” that allow you to know how much line you have
No matter which style of anchor you choose, it’s important to take extra
care when anchoring overnight. Remember that winds or currents can shift
full-circle, so be sure to position your vessel far enough away from rocks
or other vessels. In addition to regular visual checks, use the audible
anchor alarm feature on your GPS unit, which will alert you to any major