How to Identify Synthetic Fibres in Ropes
Fibres Guide
How to Identify the Synthetic Fibres Used In Rope Making
Many ropes look alike, especially with regard to material. Once a rope is removed from the reel or packing box or is otherwise separated from documentation, the material, and even the name of the manufacturer might not be easily determined.
Users frequently encounter ropes of unknown rope material. Some fibres are very similar in appearance. But important fibre rope properties such as strength, extension and durability are primarily functions of the material. Substitution of ropes of the wrong fibre material can have disastrous consequences in critical applications.
Simple observations and tests can be used to identify various fibres commonly used in ropes. Experts can distinguish some materials by appearance alone, but this is not generally reliable. Some tests can easily be performed in the field without special preparations and laboratory equipment. The burn test is the easiest to perform, but it may be impractical in some environments. Several appropriate tests should be performed for positive identification. Markings provided by manufacturers can also help in identification.
A thorough study of the techniques, practice with known fibre materials, and preparation of a few supplies will enable the user to identify most materials found in ropes. No single test should be relied upon for positive identification. Several appropriate tests should be used. When positive identification is very important, expert advice and laboratory testing should be relied on.
General information on Fibre Types
A general knowledge of the various fibre types is helpful in identifying these fibres.
The three most common rope materials are nylon, polyester, and polypropylene. Polyethylene is sometimes encountered. Some ropes are made of combinations of several of these materials.
Some ropes are now made of new fibre materials which have higher strengths than the common materials discussed above. They are also significantly stiffer, and for this reason they are usually grouped together in a category called high modulus fibres.
Sometimes the fibre material is known by its trade name instead of its common name. Some rope manufacturer's trade names identify the material. The chemical abbreviation or an acronym are sometimes used.
Table 1 gives some general identifying characteristics of the various synthetic fibres used in rope making.
Table 2 gives a brief glossary of terminology and tradenames for fibre ropes and rope materials.
Common Rope Materials
The three most common rope materials are nylon, polyester, and polypropylene. Polyethylene is sometimes encountered. Some ropes are made of combinations of several of these materials.
Nylon is generally the strongest of these common materials when dry. However, some nylon ropes lose as much as 20% of their strength when wet. Two forms of nylon are used in ropes; nylon 6 and nylon 6.6. The properties of these fibres, and the ropes made from them, are not significantly different, except nylon 6 has a lower melt point temperature.
Polyester ropes are almost as strong as nylon when dry. Polyester retains its strength when wet, and thus polyester ropes are generally stronger than nylon ropes when wet.
Polypropylene is probably the most common material found in ropes used in the marine field. One reason is that it is lighter than water, and thus it floats.
Polyethylene is uncommon in large ropes. It used water-ski ropes and other small ropes used for utilitarian purposes. It is used extensively in the fishing industry.
High Modulus Rope Materials
Some ropes are now made of new fibre materials which have higher strengths than the common materials discussed above. They are also significantly stiffer, and for this reason they are usually grouped together in a category called high modulus fibres.
Aramid was the first such high modulus fibre. It is known by the tradenames Kevlar and Twaron.
High Modulus Polyethylene (HMPE) is a special form of the conventional polyethylene discussed above and it is much stronger and stiffer than conventional polyethylene. It is known by the tradenames Spectra and Dyneema.
Liquid Crystal Aromatic Polyester (LCAP) is know by the tradename Vectran.
Trade Names and Other Terminology
Sometimes the fibre material is known by its trade name instead of its common name. Some rope manufacturer's trade names identify the material. The chemical abbreviation or an acronym are sometimes used.
For example, Dacron and Terylene are both trade names for polyester fibre. Some users call the rope by one of these names without knowing that it is actually polyester. The new high-modulus fibres, mentioned above, are usually referred to only by their respective trade names.
Table 2 lists some frequently used rope material trade names and chemical abbreviations. It also gives other common terms used for synthetic fibre rope products. This is not a complete list of trade names, and is not intended as an endorsement of the products listed. Fibre producers' and rope manufacturers' literature may be consulted for other trade names associated with a particular fibre material.
Identification by appearance
Preliminary identification can sometimes be made by the fibre appearance. This is seldom a reliable way of determining the fibre identity, but it is helpful in narrowing the number of possible fibres. Then only a few tests may be required to positively identify the particular fibre material.
Fibre Appearance
Polyester fibres and almost all nylon fibres are very fine and hair like, typically about 0.023 mm dia. These fibres are almost always white. It is virtually impossible to distinguish between nylon and polyester by appearance alone. HMPE and the multifilament form of polypropylene are very similar to nylon and polyester in appearance.
AA monofilament form of nylon (tradename Perlon), 3 to 6 mm dia., is found in some European ropes. This Atlas fibre is round, stiff, and larger in diameter than heavy pencil lead. It is usually mixed with the multifilament form of nylon in rope making.
Polypropylene is encountered in several different forms in ropes. It is sometimes a thin multifilament fibre, similar to but slightly thicker than polyester and nylon. It is sometimes a thicker monofilament, resembling straw or bristles, typically 0.1 to 0.15 mm dia. In this form it may either be a continuous fibre, or it may be cut into short lengths and then processed like natural fibres to form staple yarn. Another form of polypropylene resembles a thin tape, typically 0.06 to 0.1 mm thick. The tape is sometimes twisted so it appears to be a circular fibre. This tape may be fibrillated or split so it appears to be a collection of small flat fibres which cling to each other.
Ropes made of monofilament polypropylene are frequently black, orange or yellow. The dye helps to prevent UV degradation. White monofilament polypropylene fibres with some other form of UV protection are also common.
Multifilament polypropylene fibres are usually white. They are almost indistinguishable from nylon and polyester fibres by appearance, except they are usually slightly thicker and thus stiffer. This contrast may be evident in mixed fibre ropes.
Polyethylene fibres typically are bristle-like, in the range of 0.2 to 0.4 mm dia., and are thus similar to the monofilament form of polypropylene. Polyethylene is not damaged by ultraviolet effects, need not be dyed, and is usually natural white. However, colored polyethylene is common, especially yellow and orange. Thus it is difficult to distinguish polyethylene from monofilament polypropylene by appearance.
Aramid is a very fine straw-colored fibre. Almost all large aramid ropes have a braided jacket of nylon or polyester or are covered by an extruded polyurethane coating. Also, the individual strands are usually jacketed.
HMPE is a very fine, very slippery fibre. Some HMPE ropes are jacketed, but others are unjacketed. Sometimes a light dull-blue coating is processed onto the unjacketed HMPE rope.
LCAP, at least in the Vectran form, is a very fine tan or dirty yellow colored fibre similar to, but not as yellow as aramid. LCAP is very uncommon in rope products at the time this paper was written. Most LCP ropes will probably be jacketed.
Many modern ropes are a blend or mixture of several of the above fibres. Combinations of polyester and polypropylene fibres in ropes are common. Some, but not all composite ropes made of polypropylene and polyester are essentially as strong as ordinary polyester ropes.
Another form of mixing fibre is in the fibre extrusion process. One example is Karat, a copolymer consisting of polyester and polyethylene. This particular fibre is straw-colored.
Colored Marker Yarns
Table 3 shows the marker yarn color code specified by the International Standards Organization (ISO) and the British Standards Institute (BS) for identifying fibres in ropes. This code is also called for in the Oil Companies International Marine Forum (OCIMF) Guidelines for Large Marine Hawsers. Unfortunately, this material color code is not commonly followed.
Some rope manufacturers identify their ropes by various color marker yarns, and some of these manufacturer's markers also identify the rope material. A few of these marker color codes are shown in Table 2.
As can be seen from Table 2, the international "standard" marker yarn material code colors duplicate those used by some rope makers for other purposes. Thus caution should be taken in using such marks as a means of identifying rope materials.
Internal Marker Tapes
Some ropes have a marker tape buried within a strand. These marker tapes generally bear the name of the manufacturer, the type of material, and the year of manufacturer.
Marker tapes are required in most ropes procured by the U.S. Military in various MIL Standards. It is also required by the OCIMF Guidelines for large ropes used as SPM mooring hawsers. Some rope manufacturers include such markers in most of their rope products.
In double braid rope, the tape may be in the center of the core or between the core and the cover. In other ropes, this tape is usually within the strand which has the colored marker yarn.
The marker tape is a conclusive way of identifying a rope material, when it can be found. In an unspliced rope, the marker tape can be found by untwisting the end of a strand. In broken rope, it may be found by careful disassembly of the rope.
It may be difficult to find and examine the marker tape in a spliced rope in service. The tape usually cannot be found and removed for examination without disturbing the rope structure. However, a piece of the tape might be found and examined in the end of a splice tuck.
Identification by Testing
Simple test methods used in combination can conclusively identify most rope fibres. The following brief instructions, together with the tables, may be sufficient to conduct most of the tests.
Burn Tests
Burn testing is a generally reliable way of identifying fibres. Table 3 provides a listing of burn test characteristics. The burn test method should be used with proper precautions.
Hold a specimen of the fibre or yarn by clean forceps over a clean flame, such as a gas burner or wooden match. While the specimen is in the flame, observe the reaction of the specimen and the nature of the smoke. The smoke should be sniffed with care to determine its smell.
Remove the specimen from the flame. Observe the reaction of the specimen and its smoke and again sniffed the smoke. Any flame on the specimen should then be extinguished.
Observe the nature of the melted end of the specimen, taking care to avoid touching hot residue. Use a metal or wooden stick instead of a finger to draw out or crush the residue.
Smell alone should not be used for identification. It is influenced by coatings on the fibres, and pollutants to which the rope has been exposed. The sense of smell is not be very precise.
Specific Gravity Test
Some fibres can be distinguished by differences in specific gravities, which are listed in Table 4. Make sure that all air is removed from the yarn or fibre bundle before making a determination. Polyethylene, polypropylene, and HMPE will float. The other fibres sink in water.
A more detailed method, using a density gradient tube, is described in ASTM D276. That method might be useful to distinguish between nylon and other materials.
Melt Test
The melting point is a reliable means of distinguishing some common forms of fibres. Melt temperatures for the various fibres are given in Table 4. This test can be conducted using a calibrated melting point apparatus. The method is described in ASTM D276.
An alternate method is to place the fibre on a metal sheet, together with known fibres. Place the metal sheet on a hot plate or other controlled source of heat. Slowly raise the temperature until the unknown material begins to melt, presumably at the same time as one of the known materials.
Melt point determination is the only reliable way, other than stain or chemical testing, to distinguish between nylon 6 and nylon 6.6. It is generally not accurate enough to distinguish between materials with melt points closer than about 10°C. Thus it is not capable of distinguishing between nylon 6.6 and polyester.
Stain Test
Stain testing can be conducted with several commercially available test kits. This method can be useful in environments where burn testing is not allowed, such as on the deck of a tanker or drilling platform.
Black Rit dye is available in many stores. It can be used to distinguish between nylon and polyester. Nylon will take the dye while the polyester will remain white.
"duPont Fibre Identification Stain No. 4" is available from Pylam Products Co., 1001 Stewart Ave., Garden City, NY 11530. It can distinguishing between polyester (yellow), nylon (red), and the polyolefins (white). However, it cannot distinguish between nylon 6 and 6.6 or between polyethylene and polypropylene.
"Shirlastain A" is available from Shirley Developments Ltd., Didsbury, Manchester, M20 8SA, UK. It can distinguish between nylon 6 (pale yellow) and nylon 6.6 (dark yellow), and distinguish these from polyester (unstained).
How to Identify Synthetic Fibres in Ropes
Fibres Guide
How to Identify the Synthetic Fibres Used In Rope Making
Many ropes look alike, especially with regard to material. Once a rope is removed from the reel or packing box or is otherwise separated from documentation, the material, and even the name of the manufacturer might not be easily determined.
Users frequently encounter ropes of unknown rope material. Some fibres are very similar in appearance. But important fibre rope properties such as strength, extension and durability are primarily functions of the material. Substitution of ropes of the wrong fibre material can have disastrous consequences in critical applications.
Simple observations and tests can be used to identify various fibres commonly used in ropes. Experts can distinguish some materials by appearance alone, but this is not generally reliable. Some tests can easily be performed in the field without special preparations and laboratory equipment. The burn test is the easiest to perform, but it may be impractical in some environments. Several appropriate tests should be performed for positive identification. Markings provided by manufacturers can also help in identification.
A thorough study of the techniques, practice with known fibre materials, and preparation of a few supplies will enable the user to identify most materials found in ropes. No single test should be relied upon for positive identification. Several appropriate tests should be used. When positive identification is very important, expert advice and laboratory testing should be relied on.
General information on Fibre Types
A general knowledge of the various fibre types is helpful in identifying these fibres.
The three most common rope materials are nylon, polyester, and polypropylene. Polyethylene is sometimes encountered. Some ropes are made of combinations of several of these materials.
Some ropes are now made of new fibre materials which have higher strengths than the common materials discussed above. They are also significantly stiffer, and for this reason they are usually grouped together in a category called high modulus fibres.
Sometimes the fibre material is known by its trade name instead of its common name. Some rope manufacturer's trade names identify the material. The chemical abbreviation or an acronym are sometimes used.
Table 1 gives some general identifying characteristics of the various synthetic fibres used in rope making.
Table 2 gives a brief glossary of terminology and tradenames for fibre ropes and rope materials.
Common Rope Materials
The three most common rope materials are nylon, polyester, and polypropylene. Polyethylene is sometimes encountered. Some ropes are made of combinations of several of these materials.
Nylon is generally the strongest of these common materials when dry. However, some nylon ropes lose as much as 20% of their strength when wet. Two forms of nylon are used in ropes; nylon 6 and nylon 6.6. The properties of these fibres, and the ropes made from them, are not significantly different, except nylon 6 has a lower melt point temperature.
Polyester ropes are almost as strong as nylon when dry. Polyester retains its strength when wet, and thus polyester ropes are generally stronger than nylon ropes when wet.
Polypropylene is probably the most common material found in ropes used in the marine field. One reason is that it is lighter than water, and thus it floats.
Polyethylene is uncommon in large ropes. It used water-ski ropes and other small ropes used for utilitarian purposes. It is used extensively in the fishing industry.
High Modulus Rope Materials
Some ropes are now made of new fibre materials which have higher strengths than the common materials discussed above. They are also significantly stiffer, and for this reason they are usually grouped together in a category called high modulus fibres.
Aramid was the first such high modulus fibre. It is known by the tradenames Kevlar and Twaron.
High Modulus Polyethylene (HMPE) is a special form of the conventional polyethylene discussed above and it is much stronger and stiffer than conventional polyethylene. It is known by the tradenames Spectra and Dyneema.
Liquid Crystal Aromatic Polyester (LCAP) is know by the tradename Vectran.
Trade Names and Other Terminology
Sometimes the fibre material is known by its trade name instead of its common name. Some rope manufacturer's trade names identify the material. The chemical abbreviation or an acronym are sometimes used.
For example, Dacron and Terylene are both trade names for polyester fibre. Some users call the rope by one of these names without knowing that it is actually polyester. The new high-modulus fibres, mentioned above, are usually referred to only by their respective trade names.
Table 2 lists some frequently used rope material trade names and chemical abbreviations. It also gives other common terms used for synthetic fibre rope products. This is not a complete list of trade names, and is not intended as an endorsement of the products listed. Fibre producers' and rope manufacturers' literature may be consulted for other trade names associated with a particular fibre material.
Identification by appearance
Preliminary identification can sometimes be made by the fibre appearance. This is seldom a reliable way of determining the fibre identity, but it is helpful in narrowing the number of possible fibres. Then only a few tests may be required to positively identify the particular fibre material.
Fibre Appearance
Polyester fibres and almost all nylon fibres are very fine and hair like, typically about 0.023 mm dia. These fibres are almost always white. It is virtually impossible to distinguish between nylon and polyester by appearance alone. HMPE and the multifilament form of polypropylene are very similar to nylon and polyester in appearance.
AA monofilament form of nylon (tradename Perlon), 3 to 6 mm dia., is found in some European ropes. This Atlas fibre is round, stiff, and larger in diameter than heavy pencil lead. It is usually mixed with the multifilament form of nylon in rope making.
Polypropylene is encountered in several different forms in ropes. It is sometimes a thin multifilament fibre, similar to but slightly thicker than polyester and nylon. It is sometimes a thicker monofilament, resembling straw or bristles, typically 0.1 to 0.15 mm dia. In this form it may either be a continuous fibre, or it may be cut into short lengths and then processed like natural fibres to form staple yarn. Another form of polypropylene resembles a thin tape, typically 0.06 to 0.1 mm thick. The tape is sometimes twisted so it appears to be a circular fibre. This tape may be fibrillated or split so it appears to be a collection of small flat fibres which cling to each other.
Ropes made of monofilament polypropylene are frequently black, orange or yellow. The dye helps to prevent UV degradation. White monofilament polypropylene fibres with some other form of UV protection are also common.
Multifilament polypropylene fibres are usually white. They are almost indistinguishable from nylon and polyester fibres by appearance, except they are usually slightly thicker and thus stiffer. This contrast may be evident in mixed fibre ropes.
Polyethylene fibres typically are bristle-like, in the range of 0.2 to 0.4 mm dia., and are thus similar to the monofilament form of polypropylene. Polyethylene is not damaged by ultraviolet effects, need not be dyed, and is usually natural white. However, colored polyethylene is common, especially yellow and orange. Thus it is difficult to distinguish polyethylene from monofilament polypropylene by appearance.
Aramid is a very fine straw-colored fibre. Almost all large aramid ropes have a braided jacket of nylon or polyester or are covered by an extruded polyurethane coating. Also, the individual strands are usually jacketed.
HMPE is a very fine, very slippery fibre. Some HMPE ropes are jacketed, but others are unjacketed. Sometimes a light dull-blue coating is processed onto the unjacketed HMPE rope.
LCAP, at least in the Vectran form, is a very fine tan or dirty yellow colored fibre similar to, but not as yellow as aramid. LCAP is very uncommon in rope products at the time this paper was written. Most LCP ropes will probably be jacketed.
Many modern ropes are a blend or mixture of several of the above fibres. Combinations of polyester and polypropylene fibres in ropes are common. Some, but not all composite ropes made of polypropylene and polyester are essentially as strong as ordinary polyester ropes.
Another form of mixing fibre is in the fibre extrusion process. One example is Karat, a copolymer consisting of polyester and polyethylene. This particular fibre is straw-colored.
Colored Marker Yarns
Table 3 shows the marker yarn color code specified by the International Standards Organization (ISO) and the British Standards Institute (BS) for identifying fibres in ropes. This code is also called for in the Oil Companies International Marine Forum (OCIMF) Guidelines for Large Marine Hawsers. Unfortunately, this material color code is not commonly followed.
Some rope manufacturers identify their ropes by various color marker yarns, and some of these manufacturer's markers also identify the rope material. A few of these marker color codes are shown in Table 2.
As can be seen from Table 2, the international "standard" marker yarn material code colors duplicate those used by some rope makers for other purposes. Thus caution should be taken in using such marks as a means of identifying rope materials.
Internal Marker Tapes
Some ropes have a marker tape buried within a strand. These marker tapes generally bear the name of the manufacturer, the type of material, and the year of manufacturer.
Marker tapes are required in most ropes procured by the U.S. Military in various MIL Standards. It is also required by the OCIMF Guidelines for large ropes used as SPM mooring hawsers. Some rope manufacturers include such markers in most of their rope products.
In double braid rope, the tape may be in the center of the core or between the core and the cover. In other ropes, this tape is usually within the strand which has the colored marker yarn.
The marker tape is a conclusive way of identifying a rope material, when it can be found. In an unspliced rope, the marker tape can be found by untwisting the end of a strand. In broken rope, it may be found by careful disassembly of the rope.
It may be difficult to find and examine the marker tape in a spliced rope in service. The tape usually cannot be found and removed for examination without disturbing the rope structure. However, a piece of the tape might be found and examined in the end of a splice tuck.
Identification by Testing
Simple test methods used in combination can conclusively identify most rope fibres. The following brief instructions, together with the tables, may be sufficient to conduct most of the tests.
Burn Tests
Burn testing is a generally reliable way of identifying fibres. Table 3 provides a listing of burn test characteristics. The burn test method should be used with proper precautions.
Hold a specimen of the fibre or yarn by clean forceps over a clean flame, such as a gas burner or wooden match. While the specimen is in the flame, observe the reaction of the specimen and the nature of the smoke. The smoke should be sniffed with care to determine its smell.
Remove the specimen from the flame. Observe the reaction of the specimen and its smoke and again sniffed the smoke. Any flame on the specimen should then be extinguished.
Observe the nature of the melted end of the specimen, taking care to avoid touching hot residue. Use a metal or wooden stick instead of a finger to draw out or crush the residue.
Smell alone should not be used for identification. It is influenced by coatings on the fibres, and pollutants to which the rope has been exposed. The sense of smell is not be very precise.
Specific Gravity Test
Some fibres can be distinguished by differences in specific gravities, which are listed in Table 4. Make sure that all air is removed from the yarn or fibre bundle before making a determination. Polyethylene, polypropylene, and HMPE will float. The other fibres sink in water.
A more detailed method, using a density gradient tube, is described in ASTM D276. That method might be useful to distinguish between nylon and other materials.
Melt Test
The melting point is a reliable means of distinguishing some common forms of fibres. Melt temperatures for the various fibres are given in Table 4. This test can be conducted using a calibrated melting point apparatus. The method is described in ASTM D276.
An alternate method is to place the fibre on a metal sheet, together with known fibres. Place the metal sheet on a hot plate or other controlled source of heat. Slowly raise the temperature until the unknown material begins to melt, presumably at the same time as one of the known materials.
Melt point determination is the only reliable way, other than stain or chemical testing, to distinguish between nylon 6 and nylon 6.6. It is generally not accurate enough to distinguish between materials with melt points closer than about 10°C. Thus it is not capable of distinguishing between nylon 6.6 and polyester.
Stain Test
Stain testing can be conducted with several commercially available test kits. This method can be useful in environments where burn testing is not allowed, such as on the deck of a tanker or drilling platform.
Black Rit dye is available in many stores. It can be used to distinguish between nylon and polyester. Nylon will take the dye while the polyester will remain white.
"duPont Fibre Identification Stain No. 4" is available from Pylam Products Co., 1001 Stewart Ave., Garden City, NY 11530. It can distinguishing between polyester (yellow), nylon (red), and the polyolefins (white). However, it cannot distinguish between nylon 6 and 6.6 or between polyethylene and polypropylene.
"Shirlastain A" is available from Shirley Developments Ltd., Didsbury, Manchester, M20 8SA, UK. It can distinguish between nylon 6 (pale yellow) and nylon 6.6 (dark yellow), and distinguish these from polyester (unstained).
The Different Types Of Rope
by Chris Riley Updated on . In Nautical Knots
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Rope is one of the most important pieces of marine equipment out there, and while there’s no shortage of literature about hull types, the best anchors you can buy, SOS distress signals, there’s not enough written about rope, rope types, and the different properties, uses, and marine applications of this useful tool.
In this article, we’re going to take a look as synthetic ropes and natural fiber rope types, learning about their pros and cons, their different uses, and understanding which ones will work best in challenging marine environments.
Not all ropes were created equal! Here’s all you need to know.
What are the different types of rope?
There are many materials used today to make rope; synthetic fiber, natural fiber, and wire. The most popular is nylon, a tough and durable synthetic. It is strong, holds up well to the weather and stress, and coils without kinking. The line is also made from natural fibers like cotton and hemp (manila rope), and other synthetic fibers such as Dacron, Kevlar, and polypropylene.
No matter what material your rope is made from, they’ll all have similar construction. A rope is a group of fibers that have been braided or twisted together to create a larger, stronger cord.
A braided rope is made from a number of strands that have been woven together to create a strong line. They come in different varieties with differing numbers of strands used. Some have a twisted braid construction in the core, while others do not. Since they’re so strong, they’re particularly good for climbing rope and often used for outdoor pursuits and a wide range of different purposes.
A variety of braided lines are available:
- Braid on Braid has a braided core inside a braided sheath – will stretch less, and has less flexibility, than a hollow braid.
- Multibraid is braided with 2 pairs of Z-laid and two pairs of S-laid strands – these braided ropes are flexible and won’t kink.
- Parallel Core has a braided sheath over a core of straight or lightly twisted yarns – it is very strong.
- Hollow Braid has no core – it is very flexible but can flatten during use. It is only found in small-sized rope.
Twisted rope is one of the more popular rope choices. This type of rope is usually made from three strands that are twisted into a strong and tight cord. Traditionally, a twisted rope is made from gathered fibers that are spun into durable yarns. The yarns are then twisted into strands, which are then laid into rope. Compared with braided rope, twisted versions usually have a greater rope thickness.
There are other variations of rope type out there, such as solid braid rope, Kernmantle rope, plaited rope, endless winding rope, and some braided ropes that use a combination of the two mentioned above (a twisted braid construction). Now let’s look at the different rope materials out there.
Types Of Rope: Synthetic
Polypropylene Rope
Polypropylene line is the least expensive of the synthetic lines, however, it deteriorates quickly from ultra-violet rays and wear. It is not a good line for dock line because its hard surface tends to slip from cleats and can cause cuts if it runs free through your hands. It also has poor abrasion resistance. It floats, so it is good for rescue lines. It is also appropriate for ski lines, dinghy painters, short mooring pendants, or other applications where you want to be able to see the line on top of the water. Polypropylene rope shouldn’t be used as dock, anchor, or towing lines.
Nylon Rope
Nylon rope has a lot of stretch (up to 40%) and is very strong for its size, allowing it to absorb shock loads well. However, when it is wet it can lose up to 25% of its strength. It wears well, resists mildew and rot, and does not float. Nylon three-strand rope braided together is the preferred line for dock lines since it stretches sufficiently to dampen the shock of wave action and wind against your cleats. Just make sure it does not stretch too much for the situation in which you use it.
Polyester Rope
Polyester rope wears better than polypropylene, is almost as strong as Nylon, and retains its strength when wet. It does not stretch as much as Nylon and does not float. It’s the most abrasion-resistant of the synthetic rope types, and high abrasion resistance is very important if you want a long-lasting rope. For that reason, Polyester (such as Dacron) is used for sailboat running rigging, anchor rode, towing lines, and other applications where you don’t want line stretch to interfere. It will, however, chafe easily so check it often and protect it as necessary.
About Synthetic Rope
When cutting synthetic rope, prevent the ends from fraying with a temporary binding or whipping. Synthetic rope ends can be sealed by melting, either with a special heat tool for the purpose of cutting and sealing (as shown in photo), or by melting over a flame to fuse the fibers. Adhesive tape wound around the ends can be a temporary binding. Small line ends can be dipped into acetate glue or a commercial “liquid whipping” material. Plastic heat-shrink tubing is also available.
Synthetic lines are lighter and stronger and more rot-resistant, generally, than natural fiber ropes. Synthetic lines are slipperier than natural fiber ropes so be sure to check your knots to make sure they are secure. Synthetic lines should be cleaned with fresh water and detergent, kept out of sunlight, inspected frequently for chafe, and stored dry.
Types Of Rope: Natural
In all honesty, modern boaters shouldn’t use natural fiber for ropes. Synthetic ropes are so much more efficient. It used to be that penny-pinching sailors would use natural fiber ropes to save money, but these days real natural fiber rope is hard to come by, and it’s generally more expensive because of that very reason. However, it does still turn up on deck, but usually in the form of a rustic decoration. Why has natural fiber rope gone out of fashion? Here’s why.
Natural materials such as manila, sisal, hemp, and cotton will shrink when they get wet and also tend to rot or become brittle. Manila is still used today on large ships and is the best natural fiber for mooring lines, anchor lines, and as running rigging. Manila rope has a minimum of stretch and is very strong. However, it’s only about half as strong as a comparable-sized modern synthetic line.
A natural fiber line should be uncoiled from the inside of a new coil in order to prevent kinks. Always whip or tape the ends of natural fibers to keep them from unraveling. When natural fiber lines have been in salt water you should rinse them in fresh water and allow them to dry thoroughly. They should then be properly coiled and stored on grates above deck in a dry, well-ventilated place to help prevent mildew and rot.
What are the safe working loads for different ropes?
Knowing the maximum safe working load for a line can help prevent accidents and tragedies. You should never stress a line anywhere near its breaking strength. As a line is spliced, stretched, wears, is subjected to sustained loads, shock loads, loads of many times the recommended working load, subjected to great heat or ultraviolet light for long periods of time, it will continually lose some of its strength. Every time a knot is tied in the rope, it will lose some of its strength–and that includes all practical marine knots. Each line should be inspected prior to using it in extreme load conditions and if chafe, excess dirt, cut or worn strands, stiffness or hardness are found the line should not be used.
Important: Do not allow anyone to stand in line with, or within 45 degrees on either side, of a line under tension. Should the line part, the recoil force may cause serious injury.
Safe working load is generally thought of as no more than 1/5th of a line’s breaking strength. Said another way, the breaking strength should be five times the weight of the object the line is going to hold. You are not expected to memorize the tables below but you should remember this 5 to 1 safety rule. You should always choose a line with its intended safe working load in mind. The American Boat and Yacht Council has published charts of safe working loads for various types of line and are outlined below.
In Summary: What Is The Best Type Of Rope For Boating?
As attractive as old school twisted rope made from natural materials might be, there’s no replacement for modern, synthetic rope when it comes to marine applications. We recommend that you keep a variety of different rope kinds in stock but if we had to choose one above the rest, we would always recommend a good Nylon rope. A strong braided Nylon is easy to splice, affordable, and very strong. It’s useful for mooring, docking, and a number of other purposes.
