Many cruisers believe an all-chain anchor rode is always superior to rope rode. Chain is stronger and much more chafe resistant than rope, but you can still do some serious anchoring on rope alone. With rope you do need to be more security conscious and must always check for chafe. If there is coral on the bottom, this means diving on the rode on a regular basis. You should also be much quicker to set a second anchor, not only as insurance when conditions get strong, but also to keep your boat from swinging around too much.
One big advantage of chain is that its great weight keeps a boat from shifting around much in a light to moderate breeze or current. The big disadvantage, of course, is that this same weight hurts a boat’s performance when sailing, an effect that is only magnified when the chain is carried all the way forward in the bow, as is normally the case. If there’s a lot of chain aboard, the best arrangement is to store it as low as possible in the middle of the boat. Very few boats are set up this way, but it can be done.
A small cruising boat anchored on twin rope rodes. This is a good idea when anchoring among boats lying to chain rodes, as it keeps you from swinging into them. Untangling twin rope rodes, however, is always an issue. If you keep one in a bucket or bag this is easier to do
The normal arrangement is to stow one or two chain rodes in the forepeak. On small boats especially this will hurt performance
Because of its great weight, having a chain rode normally means you must also have a windlass. On boats less than 35 feet long you can haul chain by hand if you are strong and resilient. But even on a small boat, if you don’t want to install and maintain a windlass you’re much better off with rope. Note too you must be careful when fitting a chain rode to a windlass. Chain sizes are not standardized, and the link sockets on a windlass wildcat must fit the chain links perfectly for the chain to run smoothly.
Carrying a lot of rope rode up forward doesn’t really hurt a boat’s performance. Indeed, 200 feet of 5/8-inch nylon rope only weighs about 30 pounds, compared to about 350 pounds for a similar length of equally strong 3/8-inch chain. This means rope is actually light enough that it can be stored right on deck if you like, which does have certain advantages. Some bluewater cruisers carry their anchor line on large permanently mounted spools on deck, as this makes it very easy to both deploy and recover the line quickly and neatly. When coastal cruising in a boat with a belowdeck rode locker, I have often stored rope rode in open coils on the foredeck to save the trouble of pulling it through the hawsehole and to keep the mud it picks up from getting below.
Rope rode stored on deck during my cruise up the Gambia River
When using a rope rode, there should always be a chain leader on it to help the anchor set properly and to reduce the chance of the rope chafing on the bottom or on the anchor itself. A chain lead should be at least 30 to 50 feet long, depending on the size of the boat. An excellent compromise, particularly on smaller boats, is to put a long chain lead, say 60 to 100 feet, on a rope rode, as this offers much of the security of anchoring on chain, but is not so heavy as to unduly affect performance. Many modern windlasses now have special chain gypsies that can transition smoothly from chain to rope when hauling rode aboard.
Rope rode with chain leader. Note the neat splice at the transition point. This is the strongest connection and helps a windlass shift from one to the other
Rope rodes should always be three-strand nylon, as this sort of rope, thanks to both its material and structure, stretches very easily and does a great job of absorbing shock loads. The standard rule is that the diameter of a nylon anchor rode should be about 1/8 inch for each 10 feet of overall boat length. When anchoring on chain you should also always secure the rode to the deck with a nylon snubbing line, as chain is not at all elastic and efficiently transmits shock loads to any hardware it is fastened to. The longer and heavier the snubbing line, the better.
Three-strand nylon rope deconstructed. Nylon is much stretchier than polyester, and three-strand is stretchier than double-braid, and when anchoring stretchy is good!
Nylon snubber on a chain rode. This one could be longer. If you make the snubber super long and leave a large bight of chain under the water behind it, the bight can act as a kellet
Most anchor chain is galvanized steel, though very fancy boats sometimes carry stainless steel chain instead. There are various types of galvanized chain available. High-test chain is the strongest for its weight. BBB chain is both weaker and heavier than high-test, and proof-coil chain is a little lighter than high-test and slightly weaker than BBB. The rough rule of thumb when sizing chain to a boat is that the chain’s minimum breaking strength should be at least half the boat’s displacement. For example, a boat displacing 12,000 pounds requires a chain rode with a minimum breaking strength of 6,000 pounds or more.
Where did that “rough rule of thumb” come from on displacement vs. chain MBS?
Chain is rarely stronger than nylon rode. 3/8 BBB has a load limit of about 2650 lbs. Even Grade 43 3/8 chain only has a load limit of 5400 lbs. Samson Proset nylon has a strength of 5700 lbs for 1/2″, 9000 lbs for 5/8′, and 12,200 lbs for 3/4″.
A 12,000 lb boat will probably be about 35′ or so. 1/2″ BBB has a load limit of 4500 lbs, To be over the 6000 lbs breaking you suggest 7/16″ G43 is needed for a load limit of 7200 lbs. Pretty heavy in the bow locker.
I think you will find many heavier boats 40′ and over with 3/8 BBB (2650 lbs) or 3/8″ G43 with its load limit of 5400 lbs.
All chain specs from Acco.
What do you think of 8 plait nylon instead of the traditional 3 strand? I’m told it’s easier to handle and rarely hockles. But maybe it’s less durable than 3 strand?
Chain load limit is normally 3 times lower than breaking strength, or a safety factor of 3 in this type of application. The rule of thumb uses breaking strength, making the chain sizes quite reasonable. By this measure, the 5/16″ G4 chain (breaking strength of 11,600 lbs, but working load limit of only 3,900 lbs) that I use on my 20,000 lb boat is right at what is recommended by this rule of thumb.
Lots of good information here. Two anchors, one all chain 5/16 for 15 ton boat with CQR 45 150 ft, one 22lb Danforth 30 ft chain 200 ft 5/8 3strand. The rode kept on deck when in sheltered waters. Ends tied off with several strands of 1/8, so in emergency they can be cut ,buoyed off and slipped quickly. Chain hook drilled so it can be tied to the chain to prevent it falling off, always leave lots of slack in the chain to the snubbing line to keep noise down. Have a removable pin to capture the chain on the roller or it sure will come loose when your on a side trip and tear up the rail. Have a 10ft length of chain for the Danforth in case you anchor in a rough sea to use to retrieve the anchor safely.( anchored off angelfish cut waiting for the tide on , all chain, hooked coral, broke the roller which sailed past my wife’s ear) (had to anchor on the banks in high seas, soft sand with Danforth and plenty of stretchy rode). Remember sailboats will swing to the currant (keel), powerboats and cats will swing to the breeze. I’ve seen a sailboat on all rode do a 200 ft circle ALL night in ST Augustine . Watch out for foreign boats on polyester(Floating) rode (hook your keel, or your dingy in the dark).