FIBER ROPE GENERAL INFORMATION

Technical Resources

CERTEX USA provides abundant resources for fiber rope.  

3 and 8 Strand Constructions

Snapback: A serious hazard is created when a line under load parts because it will recoil at a high speed. A person positioned in the recoil path could be seriously injured if struck by the recoiling line. It’s the responsibility of the user to know and use the proper techniques for the particular application.
Sunlight: All synthetic fiber ropes will undergo degradation with time when exposed to sunlight. Polypropylene is far more susceptible to UV degradation than polyester or nylon. To prolong the life of your ropes, avoid storing them in direct sunlight.
Chemical: Synthetic fibers have good chemical resistance.
However, exposure to harsh chemicals (i.e. strong acids and alkalis) should be avoided.
Damage: Inspect ropes frequently for any signs of damage or wear. Retire any rope that has been cut or is heavily abraded.
Linear Density: Average with maximum 5% more than listed.
Tensile Strengths and Working Loads: As shown in our literature, these strengths are the approximate average for new rope tested under ASTM (D-4268) or Cordage
Institute test methods. The tensile strength is the load at which a new rope tested under laboratory conditions can be expected to break. However, to estimate the minimum tensile strength of a new rope, reduce the approximate average by 15%.
(Cordage Institute defines minimum tensile strength as two standard deviations below the average tensile strength of the rope). Age, use and the type of termination used including knots will lower tensile strength significantly.
The Cordage Institute specifies that the Safe Working Load of a rope shall be determined by dividing the Minimum Tensile Strength by the Safety Factor. Safety factors range from 5 to 12 for non-critical uses. The working load is a guideline for the use of a rope in good condition for noncritical applications and should be reduced where life, limb, or valuable property are involved, or for exceptional service such as shock, sustained loading, severe vibration, etc.
Stretch Characteristics: Desired stretch is determined by the way in which the rope is used. High stretch rope (nylon) with good energy absorption, is preferred for mooring, anchoring and towing, while low stretch ropes (Dacron, Kevlar, Spectra) are preferred for applications where positioning is critical and energy absorption and high stretch are not desired.

Polypropylene

Polypropylene
Nominal Size Linear Density (Lbs./100Ft.) New Rope Tensile Strength (Lbs.)
Diameter Circumference
3/16 5/8 .70 720
1/4 3/4 1.20 1,130
5/16 1 1.80 1,710
3/8 1 1/8 2.80 2,440
7/16 1 1/4 3.80 3,160
1/2 1 1/2 4.70 3,780
9/16 1 3/4 6.10 4,600
5/8 2 7.50 5,600
3/4 2 1/4 10.70 7,650
13/16 2 1/2 12.70 8,900
7/8 2 3/4 15.00 10,400
1 3 18.00 12,600
1 1/16 3 1/4 20.40 14,400
1 1/8 3 1/2 23.80 16,500
1 1/4 3 3/4 27.00 18,900
1 5/16 4 30.40 21,200
1 1/2 4 1/2 38.40 26,800
1 5/8 5 47.60 32,400
1 3/4 5 1/2 59.00 38,800
2 6 69.00 46,800
2 1/8 6 1/2 80.00 55,000
2 1/4 7 92.00 62,000
2 1/2 7 1/2 107.00 72,000
2 5/8 8 120.00 81,000
2 7/8 8 1/2 137.00 91,000
3 9 153.00 103,000
3 1/4 10 190.00 123,000
3 1/2 11 232.00 146,000
4 12 276.00 171,000

Polyester

Polyester
Nominal Size Linear Density (Lbs./100Ft.) New Rope Tensile Strength (Lbs.)
Diameter Circumference
3/16 5/8 1.20 900
1/4 3/4 2.00 1,490
5/16 1 3.10 2,300
3/8 1 1/8 4.50 3,340
7/16 1 1/4 6.20 4,500
1/2 1 1/2 8.00 5,750
9/16 1 3/4 10.20 7,200
5/8 2 13.00 9,000
3/4 2 1/4 17.50 11,300
13/16 2 1/2 21.00 14,000
7/8 2 3/4 25.00 16,200
1 3 30.40 19,800
1 1/16 3 1/4 34.40 23,000
1 1/8 3 1/2 40.00 26,600
1 1/4 3 3/4 46.20 29,800
1 5/16 4 52.50 33,800
1 1/2 4 1/2 67.00 42,200
1 5/8 5 82.00 51,500
1 3/4 5 1/2 98.00 61,000
2 6 118.00 72,000
2 1/8 6 1/2 135.00 83,000
2 1/4 7 157.00 96,500
2 1/2 7 1/2 181.00 110,000
2 5/8 8 204.00 123,000
2 7/8 8 1/2 230.00 139,000
3 9 258.00 157,000
3 1/4 10 318.00 189,000
3 1/2 11 384.00 228,000
4 12 454.00 270,000

Nylon

Nylon
Nominal Size Linear Density (Lbs./100Ft.) New Rope Tensile Strength (Lbs.)
Diameter Circumference
3/16 5/8 1.00 900
1/4 3/4 1.50 1,490
5/16 1 2.50 2,300
3/8 1 1/8 3.50 3,340
7/16 1 1/4 5.00 4,500
1/2 1 1/2 6.50 5,750
9/16 1 3/4 8.15 7,200
5/8 2 10.50 9,350
3/4 2 1/4 14.50 12,800
13/16 2 1/2 17.00 15,300
7/8 2 3/4 20.00 18,000
1 3 26.40 22,600
1 1/16 3 1/4 29.00 26,000
1 1/8 3 1/2 34.00 29,800
1 1/4 3 3/4 40.00 33,800
1 5/16 4 45.00 38,800
1 1/2 4 1/2 55.00 47,800
1 5/8 5 66.50 58,500
1 3/4 5 1/2 83.00 70,000
2 6 95.00 83,000
2 1/8 6 1/2 109.00 95,500
2 1/4 7 129.00 113,000
2 1/2 7 1/2 149.00 126,000
2 5/8 8 168.00 146,000
2 7/8 8 1/2 189.00 162,000
3 9 210.00 180,000
3 1/4 10 264.00 226,000
3 1/2 11 312.00 270,000
4 12 380.00 324,000

Manila (Grade A #1)

Manila (Grade A #1)
Nominal Size Linear Density (Lbs./100Ft.) New Rope Tensile Strength (Lbs.)
Diameter Circumference
3/16 5/8 1.50 406
1/4 3/4 2.00 540
5/16 1 2.90 900
3/8 1 1/8 4.10 1,220
7/16 1 1/4 5.25 1,580
1/2 1 1/2 7.50 2,380
9/16 1 3/4 10.40 3,100
5/8 2 13.30 3,960
3/4 2 1/4 16.70 4,860
13/16 2 1/2 19.50 5,850
7/8 2 3/4 22.40 6,950
1 3 27.00 8,100
1 1/16 3 1/4 31.20 9,450
1 1/8 3 1/2 36.00 10,800
1 1/4 3 3/4 41.60 12,200
1 5/16 4 47.80 13,500
1 1/2 4 1/2 60.00 16,700
1 5/8 5 74.50 20,200
1 3/4 5 1/2 89.50 23,800
2 6 108.00 28,000
2 1/8 6 1/2 125.00 32,400
2 1/4 7 146.00 37,000
2 1/2 7 1/2 167.00 41,800
2 5/8 8 191.00 46,800
2 7/8 8 1/2 215.00 52,000
3 9 242.00 57,500
3 1/4 10 298.00 69,500
3 1/2 11 366.00 82,000
4 12 434.00 94,500

Double Braid Constructions

Double Braid Polyester Double Braid Nylon
Nominal Size Avg. T.S. Weight Per 100′ Avg. T.S. Weight Per 100′
Diameter Circumference
3/16 9/16 1,200 1.1
1/4 3/4 2,000 1.9 2,200 1.6
5/16 1 3,000 3.1 3,400 2.5
3/8 1 1/8 4,400 4.4 4,900 3.6
7/16 1 1/4 6, 000 6.1 6,600 4.9
1/2 1 1/2 8,200 8.0 8,500 6.3
9/16 1 3/4 11,000 10.1 10,800 8.0
5/8 2 14,000 12.6 13,500 10.0
3/4 2 1/4 20,000 17.5 19,400 14.3
13/16 2 1/2
7/8 2 3/4 29,900 23.7 26,300 19.4
1 3 38,000 33.0 34,000 25.4
1 1/8 3 1/2 46,000 42.0 46,000 35.0
1 1/4 3 3/4 55,000 51.0 52,000 40.0
1 5/16 4 61,000 57.0 58,000 45.0
1 1/2 4 1/2 72,000 68.0 74,000 58.0
1 5/8 5 89,000 85.0 90,000 71.0
1 3/4 5 1/2 104,000 101.0 106,000 85.0
2 6 124,000 123.0 126,000 102.0
2 1/8 6 1/2 145,000 144.0 145,000 119.02
2 1/4 7 166,000 168.0 166,000 138.0
2 1/2 7 1/2 190,000 196.0 189,000 159.0
2 5/8 8 212,000 216.0 213,000 181.0
2 3/4 8 1/2 234,000 246.0 237,000 204.0
3 9 278,000 293.0 261,000 228.0
3 1/4 10 326,000 344.0 319,000 282.0