How to choose correct marine rope size

There are a number of factors in selecting the correct size marine rope for the task. The following information is intended as a start guide and does not mean a particular rope size is fit for purpose in every situation.

The most important factor if replacing rope which is used with rope clutches, rope cleats or blocks and pully hardware is to match the rope diameter to the clutches or cleats. This may not have been done in the past if you experience rope slippage through your clutches.

If you are upgrading from polyester rope to dyneema rope to improve performance and reduce stretch then the Cruising Dyneema range is designed to be replaced on a like for like diameter. The Racing Dyneema range is intended to save weight by reducing the diameter of rope for a given load however this will likely mean replacing clutches and cleats.

If you would like more advice please contact us we are happy to help.

Start guide to suitable rope diameter sizes in mm
KEEL BOATS
YACHT LENGTH METRES:
6-8
9
10
11
12
14
16
18
Main Sheet
10
10
10
12
12
12
14
16
Genoa Sheet
10
10
12
12
14
14
16
16
Spinnaker Sheet
8
10
10
10
12
12
12
14
Spinnaker Guy
10
10
12
12
12
14
14
16
Main Halyard
8
10
10
10
12
12
12
14
Genoa Halyard
8
10
10
12
12
12
14
16
Spinnaker Halyard
8
8
10
10
12
12
12
14
MOORING WARPS / ANCHOR ROPE
YACHT WEIGHT TONNES:
2
4
5
6.5
8
11
12
20
Mooring Warps Polyester
8-10
12
12
14
14
16
18
24
Mooring Warps Polypropylene
10-12
14
14
16
18
20
24
24
Anchor Warps Nylon
12
14
16
16
18
20
24
24
Anchor Warps Polyester
14
16
18
18
20
24
24
24
DINGHIES

SHEETS
HALYARDS
CONTROL LINES
Main
8-10
6
6-8
Jib
8-10
6
6-8
Spinnaker
6
4
4-6