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November 2011

Anchor basics

The fundamentals of staying put

Anchors

Prudent boaters carry at least two anchors in case one is lost or two are needed at the same time. Determining the bottom conditions you’re likely to encounter will help you decide which types of anchors to carry. Anchor size is usually determined by the size of your boat; consult your anchor manufacturer for size recommendations.

Fluke anchor

Fluke anchor: The most popular anchor, the fluke or lightweight anchor, folds flat and takes less stowage space. When the rode is pulled, the flukes swivel to either side of the shaft and burrow into the bottom.

Recommended for: Sand, mud

Not recommended for: Grass

Plow Anchor

Plow anchor: Typically found on larger boats, these heavy anchors don’t fold and are usually mounted on bow rollers for easy deployment and retrieval. When deployed, the plow section digs into the bottom. If the pull changes direction, the plow comes out and resets in a new direction.

Good for: Sand, mud, grass

Not recommended for: Small boats

Claw anchor

Claw anchor: This anchor’s rounded blade rotates in place, so it holds well even when the pull direction changes.

Recommended for: Sand, mud, grass

Rode

Rode can be all chain or a combination of chain and rope. The rode does more than tie the anchor to the boat. It forms an arc between the anchor and boat—nearly vertical at the boat and nearly horizontal at the anchor. The rode’s weight causes the arc, or catenary, which plays an essential role in the anchor’s ability to hold ground.

To be effective, the anchor’s shaft must be nearly horizontal to the bottom, so the rode must pull along the bottom, not straight up. The catenary also acts like a shock absorber, stretching when the boat is pushed by wake or wind and preventing the anchor from jerking free.

Chain is used at the anchor end to keep the rode nearly horizontal at the bottom; it also doesn’t chafe on the bottom as rope would. How much chain you should use depends on your boat’s size and stowage space. A practical estimate would be at least 10 percent of the total rode, but some boaters use as little as 5 percent chain.

Chain and rode diameters are dependent on your boat’s size. See the chart below for suggested diameters.

Boat length

Chain

Rope

Feet

Diameter in inches

Diameter in inches

Up to 20

3/16

3/8

20-25

1/4

3/8

25-30

1/4

7/16

30-35

5/16

1/2

35-40

3/8

5/8

40-45

7/16

5/8

45-50

1/2

3/4

50-60

9/16

3/4

 

 

Stay warm and look wonderful in this red ladies jacket with a navy-lined hood.

Mastering Marlinespike

Heaving line knot

Occasionally, you might need to weight the end of a line to throw it farther than you could unweighted.

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