Shipboard cable sheathing to avoid UV damage 1

[Revelation19]

We are faced with a situation where the sheathing on cables on shipboard (topside) equipment are cracking at high stress points (at bends and clamps). The cable outer sheathing is polychloroprene (neoprene) per the drawing. Then it is coated with some type of preservative. (I don't know what: - MIL-P-11520). In service they are coated by hand with silicone once a month after the equipment is hosed down. Silicone is applied by wiping it on the cable.

However, we are still experiencing the cracking on many of the cables. The required life time is about ten years for these cables as that is the overhaul period where the cables are replaced.

Any suggestions or personal experiences as to what I can do to extend the lilfe of the cables and avoid the cracking problem would be greatly appreciated.

 

[simultaneity]

If and I assume the overall environmental and light conditions apply to the sheathing, the materials are indeed exposed to high angles of open air and solar radiation, then the silicone in use to coat the neoprene is reacting to the light frequency and breaking down. Silicone is not optimal for any direct sunlight exposure. It will actually assist in the degradation by dehydrating the coated core. 10 years is a relatively short amount of meantime before failure or replacement and you would want to seek another answer to your coating other than silicone. A rubberized sealant will have better lasting characteristics, and less corrosion from oxidation and salts as well the effect in open sunlight is greatly imporoved as long as the sealant is pliable at the bends and the physical and technical configuration thresholds and absorbtion rates are within spec to the compound.
Chris Mar

 

[MvanderStelt]

An other solution is using specified wire with a cross-linked ETFE Polymer. These wires are used by most aircraft manufacters. Besides the good resistance to weathering (UV, ozone, water) its also resistant to chemicals like hydraulic fluids, de-icers, coolants, fuels and many other chemicals). Marine related products (wire and cable) most of the time are not suited for an open environment. Airframe wire is more suited.

Good luck.

Marco

 

[IRstuff]

A couple of things that are used in outdoor environments:

Auto finish clearcoat
Kynar used on aluminum roofing tiles

TTFN