6 Ropes, Lines and Knots (MaRLinespiKe seaManship)

Rope and LinesRopeRope Construction MaterialsHistorically, rope was made from naturally occurring materials such as hemp, manila, or flax and was laid in three strands twisted together. Most rope today is made from ny-lon, polyester, or polypropylene, which produces a product far superior to the ropes made from the natural materials. Other far stronger synthetic ropes, made from materials such as Kevlar or Spectra, are becoming available.Nylon rope is the most common in marine applications and is characterized by its superior strength and elasticity (it stretches). Three-strand nylon rope is three times stronger than manila rope and double- braided nylon is about four times stronger (see strength tables at the end of this chapter). For some applications, such as anchoring and mooring, the ability to stretch is a plus, but for other uses such as sheets and halyards, nylon’s stretchiness is an undesirable characteristic.Polyester rope is about as strong as nylon but doesn’t stretch nearly as much. It is commonly used for running rigging on sailboats.Polypropylene rope is about twice the strength of manila and breaks down in sunlight. Its main virtue is that it floats (unlike the other two types), which makes it useful for tow-ing water-skiers or a dinghy (because it won’t get tangled in your propeller).All three of the synthetic materials are highly resistant to rot, which is a major advantage over the natural materials. Table 6-1 on the next page compares these materials.The newer high tech materials like Spectra are about eight times stronger than manila and are much less elastic than even polyester. This makes them suitable for applications such as standing rigging, where only wire rope would suffice heretofore.

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types of RopeThe two basic types of rope construction are either three-strand or braided.

Three-Strand RopeThree-strand rope is the traditional type and consists of fibers twisted into yarns, which are twisted into three strands, which in turn are twisted into rope. Figure 6-1 shows con-struction of three-strand rope.

Three-strand rope tends to hold knots better, is somewhat more elastic, and is easy to splice.

Braided RopeBraided rope is (as you might expect) braided instead of twisted and is either single-braided or double-braided. Double-braided rope has a braided outer sheath and an inner braided core. Figure 6-2 shows a typical double-braided rope. Generally, only very small ropes are single-braided.Braided rope is stronger than three-strand, easier on the hands, and less likely to kink.

nylon polyester polypropylene

Tensile strength HighestAlmost

as high as nylon

Lowest

Elasticity Most elastic Not elastic Somewhat Shock loading Best Intermediate WorstAbrasion resistance Best Good Good

Weight Intermediate Heaviest LightestBuoyancy Sinks Sinks FloatsSun resistance Best Intermediate PoorestRot Very good Very good Very good

TABLE 6-1: Characteristics of Rope Making Materials

FIGURE 6-1: Three-Strand Rope

Ropes, Lines and Knots 377

heaving Line Knot

The heaving line knot is used to add weight to the end of a line, which can be useful when heaving a line.

Knots used to join two Lines (Bends)Carrick Bend

The carrick bend is typically used to join large diameter lines such as hawsers and steel rope. If the ends are seized it will be much easier to untie after being placed under load since it will not capsize so easily.

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Cleat hitch

Start the first turn around the end of the cleat furthest from the direction of pull on the standing part. Continue turns until the line looks like the illustration (2) below.

Now twist the bight on the end so the free end passes underneath and then slip the loop so formed around the end of the cleat and draw tight. The

finished hitch should look like the following (3) with the two lines adjacent and parallel in the center.The cleat hitch is used for securing a line to a cleat. It is mostly used for dock-lines, hal-yards, and sheets.

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trucker’s hitch—slip typeThe slip type trucker’s hitch to the right is used for the same purposes as the no-slip trucker’s hitch above; however, when the free end is released back through the eye, the knot unties. It is also a little quicker to tie.

Loop KnotsBowlineThe bowline is one of the stronger knots, it doesn’t slip or capsize, and it can be easily untied. It can be tied around objects in any size loop and can be used as a rescue sling to lift a

man out of the water. A bowline on the end of each of two lines is also a good way to join two lines together since not only does it not slip but it is also one of the stronger knots.

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Fisherman’s Knot (also angler’s Knot or Water Knot)This knot is suited to small line such as fishing line and is popular with fishermen. It’s very easy to tie, but is suitable for small diameter line only and not very good for use with rope.The two overhand knots are pulled tight together to finish the knot.

Fisherman’s eyeThe fisherman’s eye is one of the best known knots for mak-ing a loop in a fishing line.Note that this is actually the same as fisherman’s knot shown previously, but it has a loop at one end.

palomarThe palomar is a very easy knot to tie and is com-monly used for securing fishhooks. It is considered one of the stronger knots. It’s meant for small line but is secure with larger sizes too.Start by tying an overhand loop on a bight with the overhand loop passing through the eye of the hook as shown.