Selecting the Right Anchor Rode
Every boat needing an anchor needs a strong tether between the two. The anchor rode is an important part of a boat's setup and is available in a range of setups for different boat sizes and applications.
Let's start by looking at the four most common types of anchor rodes that use all-nylon, all-chain, and a mixture of both.
Small boats often use anchor rodes made of three-strand nylon because it’s lightweight, inexpensive and easier to stow than those with chains.
Although quite strong, all-nylon rodes can lack the chafe resistance of ones with chain and because of this they’re not ideal for extended use or use in rough weather.
As the rode for a lunch hook or spare anchor though, an all-nylon rode functions quite well.
|All Nylon Rodes - 3-Strand Nylon Rope
||Combination Rodes - StressFree Anchor Rope/Chain Kit
Combination rodes use a long length of three-strand nylon line connected to a short length of chain (6'-30') connected to the anchor.
The primary function of the chain in this rode type is to handle the rough bottoms that would otherwise chafe the soft nylon line.
Long scope (7:1) must be used to compensate for the lack of weight to keep the pull horizontal but the elasticity of the nylon helps reduce peak loads on the anchor and on your boat.
Small galvanised shackles connect the anchor to the length of chain, and attach the chain to the thimble on the anchor line. Remember to use the "next size up" in shackles; a length of 1/4" chain would be matched to a 5/16" shackle.
|Rope-to-Chain Spliced Rode - Anchor Rope/Chain Kits for Windlasses
||All-Chain Rodes - General Galvanised Chain Link
Rope-to-Chain Spliced Rodes:
One drawback of the normal combination rode with nylon and galvanised chain is the interface between them caused by the shackle and galvanised thimble that connects them.
While long-lasting, this connection is bulky and adds a shackle to the system that could possibly fail or lose its pin.
To overcome this, many boaters splice a nylon line directly to the last link of chain to create a sleek rode that stows easily, passes through windlasses easier than a splice/thimble, and retains about 90% of the breaking strength of the line compared to new line.
Larger boats with windlasses generally use all chain rodes to reduce the need for long scope because the chain is heavy and lies on the bottom until severe conditions are encountered and more scope may be required.
Since chain has very little elasticity, care should be taken to prevent it from becoming "bar tight" in high winds by using a snubber to help take the strain off and act as a shock absorber.
The drawbacks to all-chain rode are weight, expense, and the need for a windlass. A windlass and all-chain rode may add 300 to 600lb. in the bow and can adversely affect the performance of your boat.
An anchor windlass is used for raising and lowering the anchor chain on a boat and is available in a horizontal style or vertical, though the latter is more correctly called a capstan.
Every anchor windlass is equipped with a gypsy, the wheel or capstan on the winch that hauls the rope and/or chain up and down.
Each gypsy fits one or more diameters of line (of three-strand, twelve-strand or eight-strand construction) and specific types and diameters of chain.
The gypsy and rode must be an exact match, and most windlasses are available with a choice of gypsies to fit different line and chain types.
Anchor Rode Length:
The classic rule is to use seven times the sum of the water depth plus the boat's freeboard. Many boaters use a scope of more like five times and will compensate with more chain or more vigilance.
The simplest anchor rode involves connecting the anchor directly to a spliced nylon anchor line which is great for small boat as it's lightweight, inexpensive, and will hold well as long as the scope is sufficient.
If you own a boat over 40' of length and cruise to lots of different anchorages with a variety of seabed types, it's recommended considering an all-chain anchor rode.
Proper Scope with All-Chain Rodes:
Determining the length of anchor chain is based on the maximum water depth and the freeboard of the vessel, but since chain is so heavy, generally you can plan on using 4:1 scope.
Regardless of whether you use nylon rode, it's extremely important that boats with chain rode have some nylon at the bitter end so that the anchor rode can be cut in an emergency.
The following guidelines can be helpful in choosing the right anchor rode:
- Heavy or high windage boats should use 1/8" of diameter for every 8' of boat length
- "Normal" boats can use 1/8" diameter for every 9' of boat length
- Lightweight or low windage boats can use 1/8" of diameter for every 10' of boat length
- BBB chain should be half the line diameter (1/2" nylon line would be matched to 1/4" galvanised chain)
- Use shackles one size larger than the chain (1/4" chain would use 5/16" shackles)
In inland, coastal, and performance cruising applications, boaters should use a combination of nylon line and galvanised chain. For serious cruisers, all-chain rode may be a better solution. The trade-off is one of weight vs. abrasion resistance. For more information, check out our range of anchors, anchor ropes, winches and windlasses to find the right equipment for your vessel.