What rope should I use for a boat anchor rode?
I have a 9-metre cruising yacht with 10 metres of chain and want to replace the rope part of the anchor rode. Should I buy nylon or polyester, what diameter makes sense, and is eight-plait worth the extra cost?
Answer
Use purpose-made marine anchor rope: polyester offers controlled stretch and good handling, while nylon provides greater shock absorption. Eight-plait stows particularly well, but match the material, construction and diameter to your boat's loaded displacement and, where fitted, the windlass manufacturer's specification.
Check the windlass first
Establish whether you will recover the rode by hand or through a combined rope-and-chain windlass. The gypsy, the pocketed wheel that grips the rode, may accept only specific rope diameters and constructions. The wrong rope can slip or jam, even if it otherwise suits the boat.
Check the manual for the exact windlass model and gypsy marking. On an older boat, someone may have changed the wheel, so the original equipment list is not enough. Chain diameter alone does not establish compatibility either: link dimensions matter.
For hand recovery, choose rope you can grip comfortably. Thin rope may have adequate breaking strength but be unpleasant to haul when wet and heavily loaded. Leave enough locker space for it to drain and run freely.
Polyester and nylon
Polyester absorbs less water and stretches less than nylon. Rocna's guidance favours it for anchor rodes because excessive stretch can encourage a boat to sail from side to side at anchor. It suits arrangements where predictable handling and reduced movement matter, provided the complete system has enough elasticity to cushion snatch loads.
Nylon, also called polyamide, stretches considerably more and absorbs shock well. It suits light boats and exposed anchorages where sudden loads are a concern. Three-strand nylon can, however, harden with marine use, become awkward to handle and develop twist or kinks under load.
Neither material solves every anchoring problem. A boat's tendency to sheer also depends on windage, underwater shape and how the rode leads from the bow. Do not substitute an exceptionally low-stretch rope, such as bare HMPE or Dyneema, without designing suitable shock absorption into the system.
Match construction and diameter
Eight-plait or square-plait rope is supple and packs into less space than three-strand. It is also less prone to twisting. The extra cost is usually worthwhile if your anchor locker is shallow or you anchor frequently. Suitable ten-plait constructions can also work well.
Three-strand is generally cheaper and straightforward to splice, making it practical for a manually handled rode. Some windlasses require it; others accept selected plaited ropes.