If you have not noticed by now, boating has a vocabulary all its own. A bathroom is a head. Left is port. Right is starboard. A rope is a line. Furthermore, there are different types of lines. In boating vocabulary, the word for a line that connects an anchor to a boat is rode. The origin of the term is unclear, though some speculate that it evolved from an older English expression of a boat being “at rode” when anchored in serene conditions. Choosing the right rode for your boat and anchor can be a little tricky. Here are a few things to consider.
Choosing Between Anchor Chain and Anchor Rope
Anchor rodes are made of chain, rope, or a combination of both. Chain is very resistant to abrasion, but it is also heavy, which makes it cumbersome to lift and to store. Rope is lighter and more flexible. Flexibility is an asset in windy or choppy conditions because the rode will not pull as hard against the anchor and risk losing its hold. Most recreational boats use a chain lead of 20 or 30 feet that will place the chain where it is most likely to encounter rocks or coral, and use rope for the rest of the rode.
Size and Scope of the Anchor Rode
Three-strand nylon is the most popular type of rope used for anchor rode. It is strong, flexible, and resistant to abrasion and decay. A general rule of thumb for the diameter of the rode is about one eighth of an inch per every 10 feet of boat. In other words, if you have a 20-foot boat, you will want a rode that is at least a quarter inch thick. This might vary slightly if a boat is extremely light or heavy, or if the boat design has a high degree of “windage,” meaning its profile is such that it catches a lot of wind, putting more pressure on the rode.
Scope is the term used for the length of the rode played out for your boat. You will need to consider two things when considering the length of your rode: water depth and boat size. Of course, you will need a long enough rode to reach the bottom where you are most likely to anchor. However, the anchor holds best when there is a significant horizontal pull against it. If you anchor in 20 feet of water, you will need more than 20 feet of rode, especially for larger boats that will put more pressure on the rode and anchor. A 10:1 ratio of rode to depth is recommended for the maximum hold. For every foot of water, you will need 10 feet of anchor rode. In light winds and currents, this can be reduced to 7 or 8 feet. This means if you are anchoring in 20 feet of water, you should have a rode that is at least 200 feet long. Now you can see why an all chain rode might be unmanageable. That said, for boats over 40 feet that travel widely and are likely to encounter a variety of bottom types, an all chain rode is often recommended. This is especially true for powerboats that can bear the added weight more comfortably.
Selecting Anchor Rode for Emergency Use
Another thing to consider when choosing anchor rode length is the possible use of an anchor in case of an emergency. If your boat loses power and is drifting, dropping the anchor is often necessary to keep the boat and its passengers safe from collisions with other boats or with the shore or shoals. It is important to keep in mind the depth of the water you pass through most often as well as the depth at your anchoring destination. While you can wait for your boat to drift into shallower water before dropping your anchor, you do not want to wait too long, especially in stormy or windy conditions. If a boat picks up speed while it is drifting, anchoring can be difficult and risky. Also, shallow water is often rougher, so you will want to lower your anchor in the calmest water available to you. This may mean you will need longer rode for your anchor.
Inspect the anchor rode at least once per year to make sure that it is properly stowed and in serviceable condition. You want to make sure the rode is not tangled and can be easily played out when needed. Check any chain for rust, the rope for decay, and to make sure all the connections (anchor to rode, chain rode to rope rode) are in good condition.
Spending time at anchor can be wonderful. Some of your most memorable moments on your boat will come when you are not moving at all. Having the right equipment and using it properly can make these times even more relaxing.