In 2003, Navtec identified the opportunity to achieve specific cable specifications dictated by customer and application and purchased a custom designed, filament winding machine to CNC wind continuous fiber tow (Aramid or PBO). Two years of testing and development resulted in a machine design that can maintain accuracy in both length (+/- 1mm) and specification. Not only can cables be produced that meet customer’s specific requirements, but exact replacements can be manufactured at a later date.
Z-System cables can be ordered to equivalent rod or wire specifications, or by strength or stiffness requirements. As each Z-System cable is produced to its own specification, the length and fiber bundle can be accurately adjusted to suit any application.
When designing fiber rigging, the cable stiffness (EA) is typically matched to the equivalent Nitronic 50 rod in order to maintain the original specification. Generally, Nitronic 50 is specified with a safety factor equal to 2.5 times the working load. The strength versus modulus ratio of the PBO fiber offers approximately 50% more strength than the Nitronic 50 rod, resulting in enhanced safety.
To produce a Z-System cable, PBO or Aramid fiber is placed under constant tension and is wound continuously around two thimbles a fixed distance apart. Once the desired amount of fiber is wound, the cable is covered with three layers of protection: compression tape, seal tape, and chafe-resistant braid. Each thimble has a carbon fiber cover applied to create the only sealed end fitting in the industry. An adhesive-lined piece of heat shrink creates the seal between the cover and the mid-span of the cable, helping to prevent the strength degradation caused by UV light and moisture
For the past 30 years, Navtec has been at the forefront of yacht rigging. And for the past 20 years, we have been perfecting the performance of fiber rigging, offering the greatest combination of materials and terminations. As fi ber technology constantly evolves, the Navtec Design Team continue to deliver innovative rig solutions.
Until the introduction of PBO, Navtec Aramid rigging was the industry standard. Over the years, it has undergone as much development as any Navtec rigging product. The biconic compression fitting was redesigned in 2001 to be more efficient in its connection to the pre-made unidirectional Aramid cables. The fittings are now stronger and safer than ever before, and Aramid continues to be a successful offering in our fiber rigging product line.
Navtec was the first company to introduce a biconic compression fitting to terminate PBO. We use titanium terminations to ensure the most efficient use of strength available in a PBO fiber bundle. Because of this, Navtec biconic terminations are the safest available, when compared to other PBO termination methods.
Navtec offers many standard sizes of pre-made cable to meet a number of application requirements. These consist of unidirectional Aramid or PBO fibers assembled in a way that minimizes the constructional stretch characteristics inherent in fiber cable production. The use of Navtec biconic fittings with our Aramid or PBO cable ensures a long lasting performance upgrade for any application.
One unique aspect of the cable design is the protective coating that is extruded around the fiber bundle during the cable manufacturing process. For PBO cables it is a glossy, dark grey cover, whereas the Aramid has a matte, grey cover (Aramid also available with white cover in certain sizes). This cover seals and protects the fiber bundle from the damaging effects of UV and moisture and also provides a high level of abrasion resistance, plus low windage.