Mooring Line breaking strains

[RIJLudlow]

Does anyone know a rule of thumb for determining the minimum breaking strain for mooring lines for a given boat weight/size?

 

[PeteCooper]

If you do a google for Jimmy Green Marine, they have a chart giving recommended sizes for different materials and boat sizes - mooring and running rigging.

 

[Pye_End]

Generally you buy thicker mooring lines for handling, and to cope with chafe/ageing. Raw numbers on breaking strain of new rope may not be of particular help.

 

[25931]

A major factor is the windage of the boat.
Jim

 

[maxi]

Need them to break 'before' the deck fittings pull out !

 

[Twister_Ken]

I suspect there stronger than you think. I bought some light line for mousing, and the reel gave it a BS of 150 kg. By the time you're up to 12 or 14 mm, you could probably hoist the boat with it.

 

[DJE]

Exactly. Mine's moored with 4 warps all 16mm Nylon with a breaking load of about 6000kg each. The boat weighs about 4000kg fully loaded.

 

[William_H]

You might find in practice that you buy the largest line your cleats can reasonably handle. Rope too fat will not sit happily on a horn cleat.
As said you buy the fattest for easy handling and longest life with chafe and UV deteriation. olewill

 

[bluedragon]

In my view, breaking load expressed as machine tested tensile strength misses the point. Mooring lines break through the shock load of sudden wave or similar surge. Elasticity and length of the lines is far more important in my opinion, in order to absorb (and even damp) the "movement" of the boat without exceeding the elongation at which line breakage will occur.