Conference PaperPDF Available

About 75 years of synthetic fiber rope history

Authors:
  • Tension Technology International, LLC

Abstract

This paper is a survey review of the development of synthetic fiber ropes during the past approximately 75 years. It is partially based on discussions at a recent International Rope Technology Workshop and on the authors' recollections. It is also based on an extensive file and literature review.
About 75 Years of
Synthetic Fiber Rope History
John F. Flory, Tension Technology International, Morristown, NJ, USA, Flory@TensionTech.com
Prof. John Hearle, Tension Technology International, Mellor, UK
Hank McKenna, Tension Technology International, Weston, MA
Mike Parsey, Tension Technology International, Arbroath, UK
Abstract
This paper is a survey review of the development of synthetic fiber ropes during the past approximately 75
years. It is partially based on discussions at a recent International Rope Technology Workshop and on the
authors’ recollections. It is also based on an extensive file and literature review.
Nylon was discovered in the late 1930's and was first introduced into fiber ropes during World War II.
Since that time a number of other synthetic fiber materials have been discovered and used in ropes.
These include polyester, polypropylene, aramid, high modulus polyethylene (HMPE), and liquid crystal
aromatic polyester (LCAP). Improvements continue to be made to the properties of these rope-making
synthetic fibers. But no other significant new rope fiber making material has been introduced in the last
25 years.
The first synthetic fiber ropes were small braided parachute cords and three-strand tow ropes for gliders,
made of nylon during World War II. Many other useful rope structures have been developed since that
time. These include 8-strain plaited, 12-strand braided, double braid, multi-strand laid (wire rope
construction), parallel fiber and parallel subrope constructions.
The earliest ropes were made of natural fibers, before recorded history. With the development of steel
wire ropes in the 18th century, the use of natural fiber ropes declined. But now synthetic fiber ropes have
almost completely replaced natural fiber in all uses and have replaced wire ropes in many mooring
applications. Without large, high-strength synthetic fiber ropes, it would be difficult or impossible to
explore for and produce oil in very deep water.
The paper includes a timeline showing the evolution of synthetic fiber rope materials, rope structures, and
rope developments and uses.
Each of the contributing authors has lived through these 75 years and has spent many of these years in
careers related to the subject.
This paper will be of particular interest to users of synthetic fiber ropes and mooring systems.
Key Words – rope, fiber, fibre, nylon, polyester, polypropylene, aramid, HMPE, LCAP, buoy, mooring,
towing, tether, net
978-0-933957-43-5 ©2015 MTS
This is a DRAFT. As such it may not be cited in other works.
The citable Proceedings of the Conference will be published in
IEEE Xplore shortly after the conclusion of the conference.
INTRODUCTION
Fiber rope was one of man’s first inventions. Natural fibers were twisted into ropes long before recorded
history. But, unlike bone, pottery and metal, natural fibers decay, and thus few examples of ancient fiber
rope now exist.
Natural fiber ropes were for many purposes, including to moor ships and to rig sails, from pre-history. In
the 19th century steel chain and wire rope replaced most natural fiber rope in the most demanding
applications.
A number of synthetic fiber materials were discovered and introduced in the middle of the 20th century.
Fiber ropes then regained position and are now used in many important uses, particularly marine uses.
The attached Table is a timeline of significantly events in synthetic fiber materials, rope designs, and rope
uses over the past approximately 75 years. References are provided for many of these events. But even
extensive archival research might not accurately date all of the events, and there may be errors and
omissions.
The following narratives discuss materials, constructions and rope developments and uses separately.
There may be some repetition among these narratives.
More details on synthetic fiber material and rope properties can be found in the Handbook of Fibre Rope
Technology.1
Conventional Synthetic Fiber Rope Materials
The first “man-made” or “manufactured” fiber material was rayon, which was commercially developed in
the early 20th century. But rayon is made from cellulose and is not a synthetic material. Rayon was
widely used for tire cords, but it was not used significantly in rope making.
Nylon 6.6 was discovered by Wallace Carouthers at DuPont in 1935.2 Nylon 6 was discovered by Paul
Schlack at IG Farben in 1938. These are the two types of nylon used in ropes. The chemical name for
nylon is polyamide (PA). It is known by a number of different trade names. Nylon fiber was first used to
replace silk in women’s stockings, in 1939. The first use a synthetic material in ropes was that of nylon in
parachute cords and glider tow lines during World War II. After the war, nylon found its way into most
rope applications.
Low-density polyethylene fiber was discovered before World War II, but it was low strength and of little
use in ropes. High-density polyethylene (HDPE), with a different molecular form, was discovered in 1953.
HDPE ropes generally have much less strength than nylon, but they float. Polyethylene is not commonly
used in ropes today. (HMPE, high-modulus polyethylene is discussed later).
The polyester, polyethylene terephthalate (PET), was discovered by John Whinfield and James Dickson in
1941. It was developed as Terylene by Imperial Chemical Industries (ICI). DuPont acquired rights and in
1950 developed an improved PET fiber, marketed as Dacron. By 1953 PET polyester was in limited use in
rope making, but It was not widely used for rope until later when it became more available and less
expensive.
Isotatctic polypropylene material was discovered in 1954 and proved to be superior to polyethylene.
Polypropylene fiber was commercialized in the late 1950s. Unlike other synthetic fibers, polypropylene
fiber can be made in the rope factory. Because of the varying quality of the fiber, polypropylene rope
strength is generally significantly lower than nylon and polyester rope. However, Because of its low cost
and buoyancy, polypropylene is popular, especially for marine ropes.
Polyethylene and polypropylene are known as polyolefins. They are sometimes blended together or with
polyester in making fiber. These blended fibers can have very good strength properties.
Another form of polyester known is known as PEN (polyethylene naphthalate). PEN polyester fiber is
about twice as stiff as PET polyester but not as stiff as aramid and HMPE. PEN fiber has the same strength
as PET fiber. Several companies have produced commercial PEN fiber in recent years. There is interest in
it as an alternative for mooring systems which require a stiffer rope.3 But so far PEN polyester has seldom
been used in ropes because it is relatively expensive and availability is limited.
High Performance Fiber Rope Materials
The above fiber materials are referred to here as conventional materials. Beginning in the mid 1960s, a
new class of fiber materials was developed, referred to here as high performance, but generally called high
modulus fibers. Ropes made of these fiber materials can be as strong as steel wire rope of the same size
but are much lighter and easier to handle.
Fully aromatic polyamide (poly(p-phenylene terephthamide, PPTA), known as aramid, was first discovered
by Stephany Kwolek in 1965. It was developed by DuPont as Fiber B and later introduced as Kevlar.4 Akzo
developed a similar aramid fiber in 1973 which was introduced as a commercial product called Twaron in
the mid 1980s. Aramid ropes can experience axial compression fatigue if not maintained under tension.
Technora, a related para-armid copolymer fiber, with less tendency for axial compression, was introduced
by Teijin in 1987.
High modulus polyethylene, HMPE, fiber is made by two producers. Allied Chemical, now part of
Honeywell, introduced Spectra in 1985. DSM, then known as Dutch State Mines, introduced Dyneema in
1989. Honeywell later adopted the DSM fiber extrusion process because it was more environmentally
friendly. HMPE fiber ropes are lighter than water and have very high strength. However, these ropes tend
to continue to creep and may eventually fail under tension. DSM has now developed a grade of Dyneema
which has greatly reduced creep.
LCAP (Liquid Crystal Aromatic Polyester) fiber was developed by Celanese and introduced as Vectran in
1989. LCAP has strength and stretch characteristics similar to aramid and HMPE but has much less
tendency for axial compression fatigue and has minimal creep. However, it is more expensive.
PBO fiber was developed by the U.S. Air Force in the 1980s. Its full chemical name is poly(para-phenylene
benzobisoxazole. It is now manufactured by Toyoba under the name Zylon. PBO fiber is very strong and
very stiff, but very expensive. The use of PBO in personnel body armor was discontinued after discovery
that its strength quickly deteriorated. PBO loses about 65% strength when exposed to sunlight for six
months.5 It has been difficult to make rope from PBO. Small jacketed PBO ropes have been used as
rigging on high-performance sail boats, where they can be afforded and can be replaced after only a few
races.
M5 fiber was developed by Doetze Sikkema of Akzo Nobel in 1993.6 (The full chemical name is too long to
include in this short article.) DuPont now owns rights to the M5 technology. Small quantities of M5 fiber
have been produced, which exhibit outstanding properties. But efforts to scale the M5 fiber production
process to commercial quantities have not been successful to date.
An ePTFE (expanded polytetrafluoroethylene) fiber was introduced by Gore in 2006.7 This ePTFE fiber has
very low friction characteristics, but does not have outstanding strength properties. It is now blended with
other fibers to make ropes which have excellent bend-over-sheave service life.
There are possibilities for future advances in fibers for ropes.
Natural spider silk has about half the strength of aramid and HMPE fibers. But spider silk can absorb much
more energy because it stretches much more before it breaks. There have been successful attempts to
make spider silk proteins from genetically modifying micro-organisms or goat’s milk.8 But no company has
demonstrated a way of spinning fibers with the fine fiber structure necessary to achieve the strength of
natural spider silk.
Carbon fibers have strengths comparable to aramid and HMPE and are used extensively in composite
materials because of their very high stiffness (modulus). However, they are too brittle for most rope uses.
Carbon nanotubes are exceptionally strong, but they are inherently very short and difficult to convert into
yarns. Converting graphene into yarns is another possible approach. The goal is to develop a practical
process to produce a carbon fiber which can be made into very strong, very stiff rope. Someday it may
happen.9
Rope Constructions
The first 3-strand ropes were made before recorded history. At first such rope was made by hand, but
even the Egyptians used rope-walks and machinery. Large rope walks with rope making machines were
common in sea ports in the late middle ages. In addition to many marine, agricultural, and similar uses,
natural fiber ropes were used to drive machinery in water-powered mills and factories. The 8-strand
plaited rope structure was developed as an improved driving means in steam-powered factories. But the
introduction of electric motors made rope drives obsolete early in the 20th century.
The first large nylon 3-strand rope was produced by American Ropes in 1948.10 In the mid 1950s, Hawkins
and Tipson introduced 8-strand plaited nylon rope for ship mooring and towing hawsers.
Nylon 3-strand rope was used for climbing in the 1940s. The nylon kernmantle rope, comprising a core
group of small, parallel, twisted ropes enclosed in a braided jacket, was introduced for climbing in 1953 by
Edelrid of Germany. (Kernmantle means core and cover.) The kernmantle construction soon replaced
natural fiber and nylon 3-strand climbing ropes because it is much more durable.
The double-braid rope construction was invented by Ken Fogden and Arthur Chance of Samson Cordage in
1960.11 12 It comprises a braided core surrounded by a braided cover. This is still a popular synthetic fiber
rope design.
Hawkins and Tipson (H&T) (later Marlow) installed machinery capable of making 8-strand plaited rope as
large as 200 mm dia. (24 in. circum., size 24) in about 1965.13
A unique 7-strand (6 around 1) rope structure named Jetcore was developed by Robert Stanton of
American Manufacturing Co. in 1966.14 The core strand was comprised of helically laid nylon fibers. The
outer strands were comprised of a helically laid nylon center covered by helically laid yarns of polyester
and black polypropylene yarns, giving the rope a black and white liquorice stick appearance. This rope was
firmly laid such that it was durable and performed well on ships winches. It is still in use today.
The parallel-fiber rope structure, Parafil, was invented by Mike Parsey while at ICl in 1967.15 It comprises
many individual fiber yarns extending in parallel for the entire rope length which are enclosed in a tight
extruded plastic jacket. Parafil ropes are made of polyester and aramid. The aramid parallel-fiber rope
has very low stretch and is used as guy lines for antennas.
In 1978 Simion Whitehill set up a plant to manufacture aramid fiber rope using machinery acquired from
the Roebling wire rope plant. In the basic form, this “wire-rope” construction comprises a center core
strand surrounded by 6 outer strands laid in a helical pattern. A second layer of 12 helically wound strands
makes up an 18-strand rope, and a third layer of 18 helically wound strands makes up a 36 strand rope.
Such ropes are used for many purposes in the marine industry.
Mike Parsey, after joining H&T, and Aliedus Bosmen, of Bexco Ropes, conceived the parallel subrope
structure (parallel strand), Superline, in 1979. It comprises many subropes which extend in parallel for the
entire rope length and are enclosed by a tight braided jacket. Many other manufacturers now make
similar parallel-strand ropes, with 3-strand, 4-strand and 12-strand subrope constructions. Most
deepwater platform moorings now use the parallel subrope design.
Bridon installed machinery to make double braid rope as large as 240 mm (30 in. circ, size 30) in about
1981. Other than the parallel subrope construction ropes now used in deepwater moorings, this is
probably the largest synthetic fiber rope ever made.
The 12-strand braided rope structure was introduced by Samson Cordage in 1982.16 This construction has
become very popular for marine mooring hawsers and other purposes.
A successful reduced-recoil-risk (RRR) 4-strand rope design was developed by Sim Whitehill in 1987. The
principle is that after one strand fails, the remaining strands remain intact for sufficient time that rope
tension can be reduced or that personnel can get out of the way.17 The Cordage Institute has now
developed a special test method for this category of rope.18 Several other manufacturers now make
similar reduced-recoil-risk rope.
Puget Sound introduced a 12 x 12 rope construction in 1997.19 This construction is similar to the
conventional 12-strand rope design, except each of the 12 strands is itself a 12-strand rope.
A braided rope design blending HMPE and LCAP (Vectran) yarns was invented in 2002 by Bob Knusdon of
Celanese and Forest Sloan of Puget Sound Ropes.20 Called “BOB”, for Braid Optimized for Bending, this
specialized rope gives very good performance in cyclic bend-over-sheave service.21 It is an example of the
synergy of using several synthetic fibers together.
An advantage of wire rope is that its deterioration can be monitored by electromagnetic non-destructive
test methods. Elizabeth Huntley and others of Whitehill Manufacturing recently invented a method for
incorporating a carbon-treated yarn within the rope structure which can be detected and monitored by an
electromagnetic method. This new development may facilitate the use of synthetic fiber ropes in critical
applications where visual rope inspection is not practical.
Rope Developments and Uses
This section attempts to describe the most significant developments in synthetic fiber rope use. There are
many others that might merit mention.
Nylon was introduced before World War II, famously, to replace silk in women’s stockings. During the war,
it replaced silk in parachute cords and canopies. Nylon was also used in glider tow ropes, marine ropes
and climbing ropes during the war.22
Large nylon shipboard hawsers were used as early as 1948. By the early 1950s nylon was commonly used
for mooring lines. Nylon was much stronger than natural fiber rope and did not rot. Because of its high
stretch, it was particularly favored for towing hawsers. Natural fiber ropes were initially replaced by
smaller nylon ropes on an equivalent strength basis. But the smaller nylon rope was less resistant to
external damage. And nylon rope stretched much more before it broke. When it broke, the stretched
nylon rope recoiled and caused injuries and fatalities. Eventually, tables were complied to recommend the
sizes of replacement nylon rope.
Polyester fiber was slowly adopted into rope making during the 1950s. It was initially more expensive than
nylon and was not as strong when dry. But later it was recognized that nylon rope lost about 10% of its
strength when wet and also that wet nylon rope rapidly lost strength due to internal abrasion.23 Polyester
then became popular for many marine applications.
The first single point mooring (SPM) was installed in 1959.24 At an SPM, a tanker moors to a large buoy by
one or a pair of very large synthetic fiber hawsers while transferring oil. SPM hawsers are typically 150
and 200 mm dia. (18 to 24 in. diameter, size 18 and 24).
Polypropylene fiber was quickly adopted into rope making after its development in 1960. Although It was
not as strong as nylon or polyester, it was less expensive and it floated.
In 1966 the Gemini 11 manned space craft deployed a 30 m (100 ft) long synthetic fiber rope tether to
stabilize the capsule and create a small amount of artificial gravity.25 The tether was designed by Dr. Pete
Scala of Cornell University and manufactured by Cortland Line Co. a predecessor of Cortland Cable Co.
A double-drum traction winch system was developed by Henry McKenna, then with Ocean Systems, Inc.26
IT was installed on two dedicated tankers to offload oil from the Ekofisk SPM in the North Sea.27 The
mooring hawser was provided by Samson Cordage. This system enabled the tanker to pick up the end of
the mooring line and self-moor without the assistance of a workboat. Similar systems have now been
used on other SPMs.
Aramid fiber rope was first made by Philadelphia Resins in 1972. It was used in small mooring ropes and
instrumentation cables for buoys.28 Ropes made of the stiffer Kevlar 49 aramid supplanted steel wire for
antenna guy wires because of its high strength to weight ratio.
In the late 1970s the U.S. Navy sought solutions from industry for ship-board accidents caused by recoil of
broken hawsers. Several reduced recoil rope designs looked promising when tried on short laboratory test
machines. But these early designs were not successful when long rope lengths were tested in the field.
In 1983, the Ocean Builder 1 construction barge was to be moored alongside Exxon’s Lena tower in
approximately 300 m (1000 ft) water depth in the Gulf of Mexico. Aramid rope was selected to moor the
barge because of concern that wire mooring lines might damage the polymer coated steel cables which
guyed the tower. However, when the moored barge applied tension to the pre-installed aramid ropes,
they failed. Investigations revealed that the aramid ropes failed because of axial compression fatigue.29
Axial compression fatigue is now better understood and can be prevented in aramid ropes by avoiding
cycling to low tensions.30
The Oil Companies International Marine Forum, OCIMF, issued the first SPM Hawser Guidelines in 1987.31
These were based on the findings of extensive research on the performance and used strength of SPM
hawsers which began in 1979.32 33
Tension Technology International, Nobel Denton and National Engineering Labs initialed the Fibre Tethers
2000 research Joint Industry Project in 1989.34 The goal was to evaluate rope materials and constructions
to moor oil exploration and production platforms in very deep water. Tests were performed on polyester,
aramid, HMPE and LCAP yarns and on different rope designs made from these materials. The results of
this JIP were then published in 2002 as The Engineers Design Guide to Deepwater Moorings.35
The first successful riser protection net was installed on the Shell Auger platform, in the Gulf of Mexico in
1993. The net was designed by Hank McKenna of Tension Technology International and manufactured by
Southwest Ocean Services. The riser protection net extends between the legs of an offshore platform and
prevents work boats from passing under the platform and damaging the drill stem or production riser.
Today they are used regularly on offshore oil platforms.
Whitehill Manufacturing Co. developed the first successful reduced recoil risk rope in 1987. The U.S. Navy
readily adopted these ropes to enhance deck crew safety.
Aramid and HMPE mooring lines were tried on tankers and other vessels during the 1980s. HMPE ropes
installed to replace wire mooring lines on the Exxon Baytown (later SeaRiver Baytown) in 1990 lasted 8
years, about twice the expected life of the wires.36 Although these high-performance fiber ropes were
much more expensive, they and proved to be more economical because they lasted much longer and
saved time when docking the tanker, and especially because they reduced crew injuries. High-
performance mooring lines are now commonly used on vessels.
The first deepwater platform to utilize a synthetic fiber rope mooring line was the Petrobras P-IX, moored
in 230 m (755 ft) water depth off the coast of Brazil in 1995. It tested a polyester rope in one mooring leg.
Cesar Del Vecchio contributed much to Petrobras’ pioneering efforts in the use of synthetic fiber ropes in
offshore moorings.37 Petrobras installed polyester mooring lines on 27 other platforms through the year
2008.38
Shortly after its introduction, LCAP Vectran was used in ropes and cables for special applications which
require minimum creep. An example is halyards on competition sailing yachts. One of the most exotic
applications of Vectran rope was to support a large acrylic water-filled hemisphere within a deep mine
cavity in Sudbury, Ontario, which is used to detect neutrinos from outer space.39
ABS issued the first guidelines for the use of synthetic fiber ropes in deepwater mooring systems in 1999.40
API issued similar guidelines in 2001.41 These guidelines facilitated the design and approval of the use of
synthetic fiber rope platform moorings in the Gulf of Mexico. Both of these have recently been completely
revised and reissued.
Research sponsored by the Oil Companies International Marine Forum (OCIMF) in the early 1980s revealed
that wet nylon rope quickly loses strength during cycling due to internal abrasion, but that the use of
“marine grade” finishes can lessen this problem. The Yarn-on-Yarn (YoY) abrasion test method was then
developed by John Flory, John Hearle and Mustafa Goksoy.42 The YoY abrasion test method was finally
adopted by OCIMF when the SPM Hawser Guideline was republished in 2000.43 ASTM and the Cordage
institute also published the YoY abrasion test method at that time.44 45
The honor of the first synthetic rope deepwater platform mooring system in the Gulf of Mexico was
virtually a tie between the BP Mad Dog and Kerr-McGee Red Hawk platforms, both installed in the spring
of 2004. Mad Dog used Marlow polyester ropes in 1,348 m (4,420 ft) of water.46 Red Hawk used Whitehill
polyester rope in 1,615 m (5,300 ft) of water.47 At this time, 16 synthetic fiber platform deepwater
mooring systems have been installed in the Gulf of Mexico.
The weight of rope used to lower and lift objects is of particular concern in deepwater. The practical limit
on the use of steel wire is about 2000 m (6,500 ft). Several deep-water winching systems were recently
developed to employ synthetic fiber rope. The Deep Tek heave-compensated winch, using Cortland’s 12X
12 rope, was used in 3,000 m (10,000) water depth in 2004.48 The ODIM CTCU (Cable Traction Control
Unit), using Cortland’s “BOB” rope, was used in water depths over 2500 m (8000 ft) in 2006.49
One of the “blue-sky” applications for fiber rope is the space tether elevator. The concept was first
published by Yuri Artsutanov, in Pravda in 1960. A very high strength rope would be deployed from a
geosynchronous satellite down to the earth, and payloads could then be lifted into outer space using very
little energy. A recently published feasibility study evaluates the use of carbon nanotube rope for this
endeavor.50 If this works, some day, some of you may be spending a vacation in outer space.
Conclusions
One of the tools of technology forecasting is to do technology hindcasting. At the beginning of our careers
(in the case of the authors, about 1960), what would we have predicted of the future of rope technology,
and would we have believed predictions of what actually happened by the year 2015?
Another way of looking at 75 years of synthetic rope history is the rate of introduction of new materials.
In the fifty years beginning in 1940, seven new materials were introduced into rope making: nylon,
polyethylene, polypropylene, polyester, aramid, HMPE and LCAP. That is one new rope making material
about every seven years. In the 20 years since 1990, no new, practical rope making material has been
introduced. Have we hit a barrier? Or is a new break-through material just ahead of us?
Rope constructions have continued to evolve. There are some “new” constructions which we haven’t
mentioned. And some “tweaks” in design details and quality control have been significant. The recent
introduction of a practical NDT method for fiber ropes may be very significant in overcoming the
objections that “they can’t be inspected in-situ, like wires.”
Synthetic fiber ropes are now used in applications which would have been very difficult or impossible with
natural fiber ropes, wire ropes and chains. Examples are mooring systems in water depths of 10,000 m
(3,300 ft) and tethers between satellites in outer space.
We have only mentioned some of the developments and uses of synthetic fiber ropes, with emphasis on
the marine industry. The continued efforts of rope manufacturers and rope researchers to improve
synthetic fiber rope technology will certainly “push” ropes into new uses. (Who said you can’t push a
piece of rope?)
August 14, 2015
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43 OCIMF, Guidelines for the Purchasing of SPM Hawsers, Oil Companies International Marine Form, Witherby and
Co., London, 2000
44 “Standard Test Method for Wet and Dry Yarn-on-Yarn Abrasion Resistance” ASTM D-6611, American Society for
Testing Materials, West Conshohocken, PA, 2000
45 “Test Method for Yarn-on-Yarn Abrasion, Wet and Dry” CI 1503, Cordage Institute, Wayne PA, 2001
46 Petruska, D., J.F. Geyer and A.Z. Ryan, "Mad Dog Polyester Mooring - Prototype Testing and Stiffness Model for
Use in Global Performance Analysis", OTC 16589, Offshore Technology Conference, 2004
47 Haslum, H.A., J. Tule, M. Huntley and S. Jatar, "Red Hawk Polyester Mooring System Design and Verification", OTC
17247, Offshore Technology Conference, 2005
48 Crawford, M., P. Crawford, and D. Shand, “Application and Evolution: 17.5Te, 85Te and 250Td to 3000 meters
Using a Drum Winch Approach, HMPE Fiber Rope and Efficient Offshore Vessels”, OTC 21780, Offshore Technology
Conference, 2011
49 Torben, Sverre, “Fiber Rope Deployment System For Ultra Deep Water Installations” OTC 18932, Offshore
Technology Conference, 2007
50 Swan, P., Space Elevators: An Assessment of the Technological Feasibility and the Way Forward, International
Academy of Astronautics, Paris, 2013
Table Time Line of Synthetic Fiber Rope Materials, Constructions, Uses and Developments
year Materials Constructions Developments and Uses
ancient Natural Fibers 3-Strand & 4-Strand,
C1900 Rayon (not a synthetic material) 8-Strand Plaited Rope, used as belt
drives
1935 Nylon 6.6 (Polyamide) discovered
1936
1937
1938 Nylon 6 (Polyamide) (Perlon)
discovered
1939 Polyethylene fiber produced Nylon (6.6) used for nylon stockings
1940
1941 Polyester (PET) (Terylene)
discovered
1942
1943 High-Tenacity Nylon Parachute cords, glider tow ropes,
etc., World War II
1944
1945
1946
1947
1948 Large 3-Strand Nylon rope produced Nylon Shipboard Hawsers
1949
1950 Dacron Polyester developed Nylon widely used for rope
1951
1952
1953 High-Density Polyethylene
discovered Kernmantle Rope developed Polyester used in ropes
1954 Isotatic Polypropylene discovered 8-Strand Plaited Rope, marine
mooring lines
1955
1956
1957 Polyethylene used in ropes
1958
1959 Polypropylene fiber introduced Single Point Mooring Hawsers
1960 Double-Braid Rope developed Polypropylene used in ropes
1961
1962 7-strand Rope (6 around 1)
developed
1963
1964
1965 Aramid Kevlar discovered H&T 24 in. 8-Strand Braiding
Machine Polyester widely used in ropes
1966 7-strand Jetcore Mixed Fiber Rope Space Tether, Gemini 11
1967 Parallel Fiber Rope Parafil
Table Time Line of Synthetic Fiber Rope Materials, Constructions, Uses and Developments
year Materials Constructions Developments and Uses
developed
1968
1969
1970 Aramid Kevlar (Fiber B) introduced
1971 Double Drum Traction Winch
1972 Aramid first used in ropes
1973 Aramid Twaron produced Aramid Rope Small-Buoy Moorings
1974
1975
1976
1977
1978 "Wire-Rope Construction"
developed
1979 Reduced-Recoil-Risk Rope attempts
1980 HMPE Spectra fiber discovered
Parallel Strand Rope Superline
developed
1981 HMPE Dyneema fiber discovered Bridon 30 in. Double-Braid Machine
1982 PBO development
1983 Aramid Deepwater Mooring
(unsucessful)
1984
1985 HMPE Spectra introduced Riser Protection Net (unsucessful)
1986 Copolymer Aramid Technora
discovered 12-Strand Rope developed HMPE Spectra used in ropes
1987 Copolymer Aramid Technora
introduced "Reduced Recoil Rope" developed OCIMF Hawser Guidelines
1988 LCAP Vectran discovered Aramid and HMPE Ship Mooring
Lines
1989 HMPE Dyneema fiber introduced Fibre Tethers 2000 JIP
1990 LCAP Vectran fiber introduced
1991
1992 Riser Protection Net
1993 M5 fiber discovered Reduced-Recoil-Risk Rope
1994 LCAP Vectran used in ropes
1995 Polyester Deepwater Platform
Mooring, Petrobras
1996
1997 Polyester PEN fiber introduced 12 x 12 Rope developed
1998
1999
2000 Yarn-on-Yarn Abrasion Method,
ASTM & CI
Table Time Line of Synthetic Fiber Rope Materials, Constructions, Uses and Developments
year Materials Constructions Developments and Uses
2001 ABS and API Deepwater Mooring
Guidelines
2002 “BOB”, HMPE/LCAP Hybrid Rope
developed
2003
2004 Deepwater Platforms In
Gulf of Mexico
2005 Heave-Compensated Winch Rope
2006 ePTFE Fiber introduced
2007
2008
2009
2010
2011
2012
2013
2014 NDT Method for Fiber Rope
2015
? Synthetic Spider Silk?
Carbon Nanotubes ? Space Tether Elevator ?
... Specifically for wool, the regeneration process was probably not adapted commercially as the conversion rate from wool to regenerated fibre was only 35% (Wormell, 1948). By the late 1960s, regenerated protein fibres were displaced on the market (Rijavec & Zupin, 2011) by the emergence of high-performing, cheap synthetic textiles, namely nylon in 1935 (Flory et al., 2015), polyester in 1941 (Flory et al., 2015), and rayons, developed throughout the early twentieth century (Rayon, 2016). ...
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This paper is a review of the experiences and issues with the use of polyester fiber ropes as mooring lines in deepwater applications. Early studies showed that polyester rope taut-leg mooring systems could provide better offset-restoring properties in deep water than the traditional wire rope catenary mooring systems. But there was reluctance to use such moorings without further knowledge of fiber rope properties. Polyester and other fiber ropes were studied for deepwater moorings in several Joint Industry Projects (JIP) in the early 1990s. These studies provided vital information and answered many critical questions. They showed that polyester rope has desirable stretch characteristics and very good durability for use as mooring lines. The use of polyester mooring systems was pioneered by Petrobras in the late 1990s. Mobile Offshore Drilling Units (MODU) began using polyester mooring lines in the Gulf of Mexico (GOM) in the early 2000s. The first permanent applications of deepwater polyester mooring systems in the Gulf of Mexico were the Mad Dog and Red Hawk platforms, installed in early 2004. The use of polyester and other fiber rope mooring systems into even deeper water depths will present new challenges. Stiffer ropes may be necessary to achieve desirable mooring system characteristics. Longer, larger volumes of polyester rope will be difficult to handle. More knowledge of the properties of the alternative, high-modulus, high-strength fiber ropes may be needed. INTRODUCTION Fifteen years ago there was much reluctance to use polyester and other fiber ropes in deepwater mooring systems for oil exploration and production platforms. The tendency was to continue to use and adapt wire rope mooring systems into deeper water. That skepticism has now been overcome. Polyester mooring lines are now used on platforms in Brazil, the GOM and elsewhere. The experiences have been favorable. Several polyester platform moorings survived the recent hurricanes without incident. Now there is interest in installing polyester and other fiber rope mooring systems in even deeper water. But as water depth increases, other - stiffer and stronger - fiber ropes might be preferred. This paper discusses the history, present status, and possible future of polyester and other fiber rope moorings in deep water. ADVANTAGES OF FIBER ROPES Fiber ropes have a number of advantages over steel wire rope in deepwater mooring systems. Lighter Weight. Lower Loads on Platform The principal advantage is weight. Fiber ropes are nearly or essentially neutrally buoyant in sea water. They can be used in taut-leg mooring arrangements. The advantages of the taut-leg mooring might not be obvious. Figure 1 illustrates three possible ways of mooring a floating platform in deep water. Wire rope in the form of a catenary is the traditional way of mooring platforms. However, as water depth increases, the weight of suspended wire rope increases and the downward angle of the catenary at the platform becomes steeper. This results in a large downward pull on the platform which decreases payload or increases required buoyancy. (As discussed later, the steep catenary also initially produces very little horizontal restoring force)
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The International Academy of Astronautics just approved a conclusion [“Space Elevators Seem Feasible”] when it published the study report entitled: “Space Elevators: An Assessment of the Technological Feasibility and the Way Forward.” The report addresses the simple and complex issues that have been identified through the development of space elevator concepts over the last decade. It begins with a summary of ideas in Edwards’ and Westling’s book “The Space Elevator” (2003). Out of these beginnings has risen a worldwide cadre focused upon their areas of expertise as applied to space elevator development and operational infrastructure. The report answers some basic questions about the feasibility of a space elevator infrastructure.
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The experience gained from the utilization of the synthetic fiber, high modulus polyethylene (HMPE) to carry out specialist cargo recovery using in 3000 meters water depth, using an adapted 17.5Te drum winch, has lead to the development of a patented drum profile. This profile allows the fiber rope to be spooled evenly and prevents excessive flange loading and cutting in. It also minimizes heat generation in the fiber rope compared to alternative types of winch, as the fiber rope is put through fewer bend cycles. This enabling technology has been harnessed by Expro AX-S to deploy and recover its innovative light well intervention system capable of working down to 3000 mwd, using an 85Te actively heave compensated fiber rope drum winch operating from a 120m, DP2 monohull. The drum profile has also been incorporated into the established design of an offshore deck crane to deploy and recover 250Te to 3000 mwd. These developments have only be made possible by a combination of calculated risk taking, to be some of the first to use HMPE in deep water lifting application; backed by rigorous testing to further understand the nature and influencing factors that affect the working life of fiber rope; and the application of an integrated systems approach. The commercial goal is to open up deep and ultra deep water by providing safe, reliable and cost-effective means of deployment and recovery using readily available monohulls in combination with a synthetic alternative to steel wire rope that it weightless in water. Cargo Recovery in 3000 meters of water The global oil and gas industry has immense financial power, and yet it is often slow to adopt new technology, probably because it still makes the bulk of its revenue without having to do so. The salvage industry, however, is exactly the opposite. It can only achieve, especially in the niche activity of cargo recovery, by taking advantage of every new advance that will make its activities safer, cheaper and faster. This is why as far back as 2000 Deep Tek took the strategic decision to harness synthetic fiber for operation down to 3000 mwd, after experiencing the weight penalty of a wire wound umbilical in 1250 mwd. The properties of a wide range of fibers were investigated and HMPE was chosen, as it provided the best alternative for marine lifting application when compared to steel wire rope of the same diameter. A 3500 meter length of 28mm, 12×1 strand HMPE with standard urethane coating was purchased. A bespoke drum winch, designed to accommodate 1800 meters of 32mm diameter hoist umbilical was modified to take the extra capacity. Its Lebus grooving was made flush with a covering and new spooling gear was added in order lay on the rope in an open, crossing fashion; an idea that was taken directly from handling fiber rope on tug winches, in order to prevent ‘cutting in’. The result was the onsite proof that a drum winch could be successfully used to repeatedly deploy and recover varying loads down to 3000 meters water depth; undertaking many hundreds of cycles from the surface to the seabed and back again, and still remain within its original safe working load. The only drawback was the spooling pattern, which was uneven, was not deemed suitable for larger diameters of fiber rope for continued cycling. The quest therefore continued for a means of handling heavier loads.
Article
The benefits of synthetic fiber ropes for deepwater station keeping are now well established and their use is expanding. Nearly all current applications use a single grade of polyester fiber, but for different supports and environments this may not be the optimal choice. Properties of polyester fibers can be modified by adjusting processing parameters and there are other fibers available such as PEN, which offer higher stiffness. This study examines the benefits of intermediate stiffness fibres, stiffer than standard polyester but less stiff than the high performance fibers. The results indicate that there is scope for improving mooring line performance and reducing line weight by careful evaluation of material options. Introduction Polyester fiber ropes are finding increasing applications in offshore mooring systems as production moves to deeper water. Following successful installations offshore Brazil in the late 1990's [Pellegrin 1999] the first Gulf of Mexico mooring was for the Mad Dog spar [Bugg 2004] in 2004, which employed 1200 tons of polyester down to 1670 meters water depth. The recently installed Independence Hub platform also used polyester moorings, in 2440 meters water depth [Paganie 2007]. Different rope constructions have been used but these mooring lines were all composed of similar high tenacity polyester fibers. The Red Hawk spar [Haslum 2005], also installed in 2004, used a modified polyester fiber with a higher initial stiffness to facilitate installation, and this raised the question of whether a higher fiber stiffness might be beneficial for other supports and allow rope diameter to be reduced. Previous work within the French Mooring line project [Davies et al 2002] studied high performance fibres such as aramids and HMPE and concluded that their very high stiffness, while allowing much smaller rope diameter and weight, did not improve durability as it would result in high fatigue loading of the metallic components of the mooring line. However, there is an intermediate stiffness region, shown in Figure 1, situated between the currently used fibres, with initial tensile modulus around 10-15 GPa, and the high performance fibers (> 60 GPa) which has not been explored previously for deepwater mooring applications.
Article
The Mad Dog Floating Production System (FPS) will be the first truss spar to use polyester for a permanent mooring system. The breaking strength of the polyester ropes is also the largest ever-made being in the 2000 mT range. As such, prototype testing to validate the breaking strength capacity of the spliced ropes was important along with gathering performance data of the ropes to be used in the mooring design and global performance analyses of the FPS. Since this is the first spar to use a polyester mooring, and since loop currents typically govern the mooring of a spar in the Gulf of Mexico, a better understanding of the "static drift stiffness" or extension of the rope was required. Thus far, polyester moorings have been predominately used by Petrobras in the Campos Basin for semi-submersible FPS and Floating Production, Storage and Offloading (FPSO) units and thus only the dynamic and drift stiffness has been important. Much data is available for these two stiffness, but very little on the static drift stiffness was available. Consequently, a model had to be developed along with procedures to test the ropes to derive this stiffness. This paper will discuss the prototype test plan, which basically follows API RP 2SM but with several deviations, in particular to obtain more dynamic stiffness and static drift stiffness (extension) data over a range of mean loads, load ranges and rate of loading. In addition, axial tensioncompression fatigue testing was conducted explicitly to the mean load, range of loading and number of cycles expected to occur to the mooring while in-service to confirm this is not a problem since tension did fall below 5% of MBL. Finally a stiffness model will be presented that can be used for mooring design / global performance analyses for FPS using a polyester mooring system. Information presented in this paper will help designers of polyester mooring systems and also should impact the future revision of API RP 2SM. Introduction Petrobras has designed and installed numerous polyester mooring systems to semi-submersibles FPS and Floating Production, Storage and Offloading (FPSO) systems (Costa, 2001). However, to date, polyester has not been used in a permanent mooring system outside of the Campos Basin. BP Exploration & Production Inc. ("BP") and the Mad Dog project partners changed that when the taut-leg polyester mooring system was installed on the truss spar in early 2004. The Mad Dog project was facing a significant hurdle in trying to keep development cost down so the company and the partners, BHP Billiton Petroleum (Deepwater) Inc. ("BHP Billiton"), and Union Oil Company of California ("Unocal"), could sanction the project. In order to control cost, it was important that the hull be fabricated and transported to the Gulf of Mexico as a single piece. The size and weight of the hull was already challenging the capabilities of the worldâ??s heavy lift vessels and in addition, payload was increasing to meet topsides requirements. Thus the project team investigated using a taut leg polyester mooring system.
Article
This paper presents the design and testing of the polyester mooring system for Kerr-McGee's Red Hawk platform installed in 5300 ft water depth at Garden Banks. A new test plan was developed and used to evaluate polyester rope stiffness for extreme loop-current conditions. A relationship was observed between the final installed rope length and the loop-current stiffness behavior of the lines. The loop-current stiffness is dependent on the amount of "construction stretch" removed during installation. Different rope designs and installation procedures are evaluated. Introduction Platform offset is an important driver for design of the risers supported on the platform. For the Red Hawk cell spar, the "missing one line case" in the extreme loop current event is the governing design condition for both maximum mooring line tensions and maximum platform offset. The loop current is characterized by steady loads acting on the platform for up to several weeks. The platform offset calculation requires knowledge of the polyester stiffness characteristics during a loop current event. Unfortunately, present design guidelines do not define polyester stiffness values relevant for a deep draft floater exposed to loop current. A new test plan was developed for Red Hawk and used to evaluate different rope designs and installation procedures. Future revisions of design guidelines should include a test method to standardize the static stiffness values used for loop current offset calculation. The final installed rope length depends on the "construction stretch" removed during installation. Higher installation loads result in more permanent stretch removal and longer rope lengths. Similarly, the loop-current stiffness is highly dependent on the amount of permanent stretch removed during installation. Higher stiffness values resulting in smaller platform offsets can be achieved by exposing the rope to higher installation loads, thereby removing as much permanent stretch as practical. The ABS and API modulus test procedures, Ref. [1] and [2], both begin by loading the rope to 55% of minimum breaking load (MBL). For typical mooring installations, the mooring lines are exposed to lower peak loads than 55% MBL. Subsequent measurements made on the rope sample loaded to 55% MBL will then overpredict the loop-current stiffness and the installed rope length. For Red Hawk, stretch was removed using an anchor handling vessel and a rigging that amplified the bollard pull. The mooring requirements dictated by riser design necessitated the use of a stiffer polyester yarn previously not used in offshore mooring rope constructions. Mooring System Configuration An overview of the Red Hawk project is given in Ref. [3]. The Red Hawk cell spar is moored in 5,300 ft water depth with six evenly spread taut legs comprising of chain-polyester-chain. Figure 1 shows the hull configuration with mooring lines and topside. Figure 1: General overview of the Red Hawk cell spar (Available in full paper) The configuration of the cell spar is efficiently suited for the connection of each leg of a six leg mooring system at the junction between each of the six outer cells, see Figure 1.