Recommended Rope Sizes by Yacht Length
The table below provides indicative rope diameters for common yacht running rigging, together with general starting points for mooring lines and anchor warp. These figures are useful for planning replacement ropes but are not a specification for an individual yacht.
Final rope selection should take account of yacht size, sail area, expected loads, rope construction, handling requirements and compatibility with the sheaves, clutches, blocks and winches fitted to the boat.
| Yacht Length | Application | Kingfisher Recommended Diameter | Marlow Recommended Diameter |
|---|---|---|---|
| 6–8 m | Main Halyard | 8–10 mm | 10 mm |
| Genoa/Jib Halyard | 8–10 mm | 10 mm | |
| Spinnaker Halyard | 8 mm | 8 mm | |
| Sheets (Main/Jib) | 10 mm | 10 mm | |
| Spinnaker Sheets | 10 mm | 10 mm | |
| Mooring Lines | 10–12 mm | 8–10 mm | |
| Anchor Warp | 12–14 mm (nylon) | 12 mm (nylon) | |
| 9–11 m | Main Halyard | 10–12 mm | 12 mm |
| Genoa/Jib Halyard | 10–12 mm | 12 mm | |
| Spinnaker Halyard | 10 mm | 10 mm | |
| Sheets (Main/Jib) | 12 mm | 12 mm | |
| Spinnaker Sheets | 12 mm | 12 mm | |
| Mooring Lines | 12–14 mm | 12–14 mm | |
| Anchor Warp | 14–16 mm (nylon) | 14–16 mm (nylon) | |
| 12–14 m | Main Halyard | 12–14 mm | 14 mm |
| Genoa/Jib Halyard | 12–14 mm | 14 mm | |
| Spinnaker Halyard | 12 mm | 12 mm | |
| Sheets (Main/Jib) | 14 mm | 14 mm | |
| Spinnaker Sheets | 14 mm | 14 mm | |
| Mooring Lines | 14–16 mm | 14 mm | |
| Anchor Warp | 16–18 mm (nylon) | 16 mm (nylon) | |
| 15–18 m | Main Halyard | 14–16 mm | 18–20 mm |
| Genoa/Jib Halyard | 14–16 mm | 18–20 mm | |
| Spinnaker Halyard | 14 mm | 14–16 mm | |
| Sheets (Main/Jib) | 16 mm | 16–18 mm | |
| Spinnaker Sheets | 16 mm | 16–18 mm | |
| Mooring Lines | 16–20 mm | 16–18 mm | |
| Anchor Warp | 18–20 mm (nylon) | 18–20 mm (nylon) |
Important Sizing Notes
- Dyneema-core ropes can sometimes achieve the required strength and stretch characteristics at a smaller diameter than polyester rope, but diameter should not be reduced by a fixed rule. Check expected loads, manufacturer data and compatibility with sheaves, clutches, organisers and winches before changing size.
- Always check deck hardware compatibility—clutches, blocks, and winches have minimum and maximum diameter tolerances.
- Mooring and anchor lines have different requirements from halyards and sheets. Construction, stretch, berth arrangement, anchoring setup and expected loads should all be considered when selecting diameter and material.
Ready to Replace Your Yacht Ropes?
Use the table above as a planning guide, then choose the route that best matches what you need.