Clip-on protection is hydrodynamic
A one-piece plastic extrusion can be opened out to allow the introduction of a rope of cable and then re-zipped to close it
. It also functions as a low drag aerodynamic- or hydrodynamic-shaped fairing.
It was originally designed by yacht rigging makers Colt Systems, of Stockton on Tees, as a chafe guard for composite stays on yachts. Responding to our November 2006 Coffee Time Challenge “Protecting Cable”, Colin Pearce thought it offered a better solution to cable protection than the one we offered.
Used in yacht rigging it protects the stay from fast-moving ropes and the chafe that induces. It also reduces the windage of the rig. Not only is it aerodynamically efficient, it self-rotates in the wind to ensure minimal drag. For use on a cable, he says it could be coiled up on a workboat, and spooled onto the cable, zipping it up as it goes out.
His team also believes it could be used on mooring ropes for deep water oil and gas production facilities, where the drag on the multiple mooring ropes, up to 10,000 feet long, significantly adds to the loading on the rig and the ropes.
“It could even be used for ropes lying on the sea floor, where it will tend to reduce water current induced motion and hence wear,” says Pearce.
Furthermore, he says it could reduce wind drag on the cable superstructure of older cable-stayed bridges, which may now “be working close to or outside their safety limits”.
A commercial version is to be launched this month and a patent has been applied for.