Rope has been constructed from the materials available in the natural environment since time immemorial. Most boaters are familiar with ropes constructed of natural fibers like hemp or sisal, but are more likely to use synthetic materials with their boats.
Each material used to make a rope has its advantages and disadvantages. Different fibers are better suited for specific uses and knowing this can be a benefit to a boater during their everyday operations. Rope material characteristics can involve things like cost, strength, stretch, resistance to chemicals or sunlight, and durability. To add to the discussion, synthetic materials often bear a number of different names or trade names.
Natural Rope Construction Materials
Mariners use few ropes constructed of natural materials these days. There are still some rope manufactured from plants such as Sisal, Abaca (Hemp), and Cotton. Natural fibers are relatively short, making the lines made of them weaker than those built of manmade materials. They can easily be identified by their fuzzy surface that is hard on the hands and must be of great diameter to gain usable breaking strengths. Natural fiber ropes absorb moisture and will freeze. These materials will decay or degrade from insect, mildew, rot and fungus infestations.
Synthetic (Manmade) Rope Construction Materials
Synthetic ropes offer boaters a number of options in their application and use on a boat. One major advantage manmade rope fibers have natural materials is the overall length of their single fibers; they can feasibly be same length as the rope being built from them. The following are some more commonly seen synthetic material used in ropes used with recreational boats.
- Polyester (Terylene, Dacron) – A very strong synthetic fiber that offers good resistance to abrasion and load cycling. Polyester does not stretch like nylon, but it does wear better in repeated use. It is will suited for static loads like standing rigging and can replace wire in some cases. Polyester resists damage from acids, fuel, solvents and sunlight. Rope made from the fiber does not float. Some boater’s prefer using polyester line for storm moorings.
- Polypropylene (Polypropene) – The polypropylene material used to build a rope can be made of monofilament or multifilament fibers. Polypropylene is subject to chain degradation from exposure to sunlight and needs to be made with an UV-adsorbing additive if it is consistently used in sunlight. It will degrade through oxidation at high temperatures and has a low melting point. Polypropylene shouldn’t be used where friction generated by use of the rope is an issue. This rope is very light and floats in the water. Polypropylene is resistant to most chemicals.
- Polyethylene (Polythene) – This a widely used plastic that produces a lightweight rope that wears well and inexpensive to manufacture. Polyethylene rope is difficult to tie in a knot and it floats in the water. Knots tied with this rope are infamous for coming loose.
- Polyamide (Nylon) – This is one of the strongest materials available for construction of rope, but it does loose about 10 percent of its strength when wet. Nylon is very elastic, stretching up to 40 percent without breaking. The material is well suited for anchor and towlines were it ability to adsorb shock loads is important. Nylon resists damage from most chemicals other than acid and sunlight well. It wears well and doesn’t float in the water.
The material used to make a rope effects its performance and preferred use around a boat. Nylon is a good choice for anchoring and polypropylene could be a good product to use with a throwable ring buoy since it floats. Learning a little about rope construction materials can make for a better boater.
 |
 |
 |
