Umbilical. Tether. Cable. Control wire. Call it what you will, the electrical connection to your remotely operated vehicle is, quite literally, its lifeline. And it should be treated as such. Inuktun tethers typically provide not only the power and control signals for the vehicle, but also a strength member that allows for retrieval in emergency situations. Proper handling and storage can prevent damage resulting in costly re-termination or replacement and unnecessary down time. Here we offer a few tips for maximum tether life and reliability.
- When discussing your operational requirements with our expert team, verify that the proposed tether won’t experience problems when interacting with the environment. For example, a typical polyurethane jacketed cable will not work very well in most plastic pipes.
- If you are contemplating the required travel distance of a crawler, consider that every repair to the tether will make it shorter. We normally recommend buying the longest length possible, to reduce the chance of ending up with a system that is too short to suit your needs.
- For longer tether cables that are stored and deployed from an electric winch, always try to avoid fully unspooling the umbilical. Although the cable is protected where it is anchored to the winch drum, damage can more easily occur when it is subjected to direct pulling forces.
- With the heavier vehicles, a cable strain relief (typically a “kellems grip”) is included to insure that any pull on the cable is affected on the strength member, rather than the conductors. Always be sure that the grip is installed properly with some slack between where it connects to the tether and the back of the vehicle.
- Additional strain relief should be incorporated at the vehicle connection to minimize damage when flexing, bending or travelling around corners. This can be in the form of a spring, hose or flexible potting material.
- When setting up to perform an inspection, it is extremely rare to have the cable reel directly in line with the end of the pipe which means the tether will likely be going around multiple bends before it enters the pipe. Large diameter rotating cable sheaves should be used at every bend, instead of simply pulling the cable around a bar or the edge of the pipe.
It is important to bear in mind that the umbilical is an expensive, sophisticated multi-conductor tether, not a common electrical extension cord. To this end, do not step on, drive over, kink, over-bend, or snap load your tether. Crushing a tether can lead to premature failure and tether jacket abrasion. Take extra precautions to mark your working environment with safety cones or blockades, and ensure that operators are conscientiously managing the tether. Kinks regularly occur when there is slack tether with closing loops or when a coil slips off a full drum. Operators should read and understand the product user manual prior to operating a system, with knowledge of the maximum safe working load and minimum allowable bend diameter. And remember – your tether cable may be worth more than your car. It should be regularly inspected for damage and cleaned whenever possible.
Following these guidelines will extend the fatigue life of your tether and ensure you’re operating efficiently and economically with proper handling and care. We help you choose the best reel in this article, and our team is available to provide technical support on Inuktun’s Multi-Mission, Modular (IM3) technology.