Single or Double Braid?
All Nautilus Braid’s ropes are either braided as a single braid or a double braid.
Braided ropes have a unique advantage in that the fibres lock tighter together as the load increases. They are stable with respect to twisting because there is no unbalanced twist as found in a laid rope. (Twisted, folded or laid ropes untwist as the load increases which tends to loosen the fibre hence lowering inter-fibre friction allowing rupture to occur at much lower forces).
The Plaid of the Braid
This refers to the weave or the number of strands that make up each section of the rope. Again engineered to give the highest performance. Centres (inners) tend to be 8 plaid which gives a tightly compacted central core with the “pitch” (the length of the rope where all the strands have completed one turn) kept relatively long. These are the load bearing fibres and the straighter the better. (minimum stretch if the pitch is long – short pitch fibres would act like a spring straightening as the load increases).
The outer tends to be either an 8, (especially knobbly ropes for grip)16, 24 or 36 carrier weave; each weave having usually two or three ends of yarn depending on the diameter of the rope. The more finely twisted and the greater the number of filaments the more resistant to abrasion. However all ropes have to be spliced and using 16 or 24 carrier ropes with the correct pitch helps this operation giving the highest strength splice when the weight of the inner and outer are balanced.
Pitch also affects the ease of splicing and the flexibility and handle of the rope. If the pitch is too short the rope tends to become hard and looses flexibility, too long and the rope does not wear well and provide good service. Nautilus Braid has optimised these values for individual rope diameters balancing the pitch to give the highest performance, the best durability, ease of splicing and the least stretch.
In some special cases we use polyarylate or UHMWPE in both the inner and the outer to give special attributes like resistance to heat or friction.
The Double Braid
This structure is the time proven marine standard.
The rope consists of a low twisted compact inner braid primarily to add strength and a twisted braided outer which provides strength and abrasion resistance to stand the test of time. The outer yarns are folded in the “S” and “Z” directions and then braided so as the individual fibres lie inline with the rope itself. This stops individual fibres catching on any minor protrusions while in use. While the outer adds to the strength of the rope its primary design function is to give durability – abraison resistance.
The outer also gives the manufacturer the opportunity to add colours to distinguish individual ropes. Also Nautilus Braid has colour codes to distinguish our own ropes and the type of inner and thus recommended application the rope might have.
In the double braid structure we also use the high tech/high strength fibres in the inner for strength with a PE outer giving protection from the elements.
These tend to be used for specialist applications particularly when strength is paramount. For example, helicopter lifting strops and high performance halyards.
These single braid ropes are usually made of the high tech fibres either UHMWPE or polyarylate. With the UHMWPE yarns we usually coat the outer with polyurethane resins to give protection and durability. The polyurethane can be colour tinted to the customer’s requirements – grey is usually held in stock.
Most of Nautilus Braid’s ropes are made from high tenacity continuously spun multi-filament PE (polyester) or P.A. (Nylon) having a tenacity of around 8 gms per denier. Some special “buoyant” ropes use PP (polypropylene because of its especially low density)
We also carry new age fibre – Dyneema/Spectra (UHDPE – ultra high density polyethylene) and Vectran (polyarylate superfiber) to allow even the most discerning consumer to choose the right quality rope for the right job.