How to choose Docklines, Anchorlines and -chains
A bit like an umbilical cord, the dockline or anchorline connects your yacht with the land – either trough an anchor on the seabed, or with a dock or buoy. Obviously, that’s quite an important job and thus, it’s worth thinking about some things when choosing the line for it. In this article, I try to outline important properties a dockline or anchorline should have.
If you are new to ropes, I recommend you to read my article on Ropes in General – here you will learn about different materials used for ropes and that they generally come in two types: three-stranded and braided rope.
If you are looking for docklines or anchorlines, you should look for rope that is flexible. Inflexible rope is more vulnerable to snapping if pressure occurs suddenly. An elastic line, however, will extend to some degree and thereby, slowly absorb the energy. This is advantageous for both, the rope itself and the fittings it is tied to.
If you are using a dinghy, you should go for a simply Nylon rope with an appropriate diameter for your boat’s needs. Nylon is cheap, wonderfully flexible but strong, and very insensitive to abrasion and damages through UV light or salt. You really shouldn’t use other materials for docklines – some sailors do, but I would recommend Nylon under any circumstances unless maybe for tiny dinghies on a freshwater lake.
A marine umbilical chord - connecting boat and anchor
If you are sailing a cruiser yacht, you might take a nylon rope for your secondary anchor or kedge. For the bower or primary anchor, however, most cruisers prefer to rely on chain since it is stronger and therefore safer. The disadvantages of chain are the higher price compared to even high-quality Nylon ropes and the higher weight of metal.
Length of docklines: The length of docklines is pretty flexible, starting with as little as a single length of the boat. This applies to dinghies and depends on where you moor: a dock, a buoy or in a marina. Some sailors prefer to have at least two lengths their boat in dockline to have some flexibility and extra-rope in case of a damage.
Length of anchorlines and -chains: The length of anchorlines depends on the material and the area in which you plan to anchor. Keep in mind that you should pay out at least three times the depth of the water for chain, five times if you use a Nylon line. These are minimum values that should be increased if possible – therefore, your line or chain should extend a good chunk longer than necessary for these conditions.
Securing your boat in tidal streams
Don’t forget about the tides – they need to be taken into consideration with these estimates, too. The tidal shift is small in the Mediterranean, many sailors that are used to the conditions there get surprised by the much stronger tides pretty much anywhere in the World. I personally know an experienced Med-sailor, who once sailed into the Atlantic Ocean, stayed in a Portuguese port and found his boat hanging in the air tied to the dockline only a few hours later.
In addition, the “three times the depth” for line and “five times the depth” for chain rule applies only in good weather conditions. If you expect foul weather or even gales, might want to double the amount of line or chain you pay out. The total length of line or chain should allow such a high degree of variation to your own safety and the safety of your yacht.