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Breaking strength sheets

For most ropes we have specifications of their breaking strength in kilograms. How do you know what minimum breaking strength you require for your boat? Bear in mind that the weakest link count. An eye splice typically reduces the strength by 5-10% but a knot can take off 50% of the strength. Premium Ropes has published some instruction films for eye splicing for you. 

Genoa sheet 

For your genua you can easily calculate this by multiplying your sheet size in square meters with 30. This allows you to handle your genua by 7 Bft  (41-47knots). For regatta I typically allow a 1.5 safety measure and for cruising even 2.

size genoa (m2)

minimum loading strength (kg) for a genua sheet

regatta (safety ratio 1.5)

minimum loading strength (kg) for a genua sheet

cruising (safety ratio 2)

20 m2 - 30 m2 900 kg - 1,350 kg  1,200 kg - 1,800 kg
30 m2 - 40 m2 1,350 kg - 1,800 kg  1,800 kg - 2,400 kg
40 m2 - 50 m2 1,800 kg - 2,250 kg  2,400 kg - 3,000 kg
50 m2- 60 m2  2,250 kg - 2,700 kg  3,000 kg - 3,600 kg
60 m2 - 70 m2 2,700 kg - 3,150 kg 3,600 kg - 4,200 kg


Main sheet

Calculating the breaking strength for your main sheet is more complicated, but fortunately Harken has published a calculator


Ropes suitable for sheets are: D-Cup Kmix (regatta line with softgrip), Cruiser 24 Kmix (polyester with softgrip) or use our rope selection guide.

D-CUP KmixCruiser 24 Kmix


Helps you select the right rope for your needs: