What is the difference between Dyneema^® and Polyester ropes?

Dyneema^® and polyester are the two most commonly used materials in sailing ropes. The type of rope is chosen between these materials. Sometimes Dyneema^® and polyester yarns are also used in a combination.

But what is the difference?

Ropes made from polyester are quite common on sailing boats. Polyester is flexible, strong, abrasion-and UV-resistant. Ropes made of polyester are not expensive and offer a lot of possibilities. This fibre can be used for mooring lines, sheets, halyards and trim lines. It’s actually an all-round material. Another important property of polyester is the elongation or stretch. Whether this is a disadvantage or an advantage can differ depending on the application. For instance, we expect mooring lines to have some stretch to absorb peak loads.

Dyneema^® is also a well-known name in the marine industry. It is actually an HMPE fibre and Dyneema^® is a brand name. For example, there are also other brand names such as Spectra^® or Stirotex^®. All are HMPE fibres. Ropes made from this material are very popular. That is not surprising, because ropes made of Dyneema^® fibres are twice as strong as polyester and the material does not stretch. Dyneema^® is very smooth and has a low melting point. That is why ropes made of Dyneema^® fibres often have a polyester cover. Otherwise the ropes will not hold in the clutch or on a winch.

What type of line should I choose for my halyards or sheets?

It’s important to decide whether you want a rope with or without any stretch. An important choice because it has a lot of influence on the sailing characteristics of the yacht. A rope without elongation ensures a perfect sail trim. The sail will retain its shape and the draft of the sail stays in the right place. If a rope elongates, then the draft of the sail moves aft. Which means that the boat will not accelerate but instead leans over during gusts of wind. This is not preferred.
If the elongation of a rope is less important. For instance with sheets for cruising. Then you can use polyester ropes without hesitation. The costs can also be an important factor. Ropes made with Dyneema^® fibres are considerably more expensive than polyester.