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Underwater TerminationsUnderwater Standard Steel TerminationThe most common standard underwater steel termination in the MacArtney range is the forktermination, which will allow you to make underwater terminations to either steel armoured or Kevlar armoured cables in the range of 6-14 mm OD to carry loads up to 1250 kg and make sure that you transfer the full strength as the Safe Working Load (SWL). The standard underwater steel terminations is a safe and reliable way to hook-up your cable to your system for towing after a vessel or lifting a heavy object such as a down hole camera system. In most cases the underwater cable end is terminated and moulded to a underwater connector and thereby making the underwater cable termination completely watertight. Underwater Chamber Terminations Termination of special fibre optic and electrical steel armoured cables to special customer designed connectors is one of the many strengths of MacArtney. On steel armoured cables the mechanical stress termination is done by using cone metal parts or wire lock thereby making it possible to transfer the whole force from the cable to the steel parts. Terminating a underwater cable to a special designed underwater connector can be done by using a underwater chamber termination where you hook-up the cable to the underwater connector inside the chamber termination. The chambers can be rated and certified for up to 300 bars. The advantage of using a underwater chamber termination is that it makes it relatively easy to replace connectors and cable and at the same time making it possible to re-use the steel parts. Underwater Oil Compensation The underwater oil compensated steel termination basically works like the chamber termination; the only difference is that the chamber is oil filled. The oil compensation is either controlled through a bladder or an external reservoir. The advantage of using an underwater oil compensated system is that the system can be certified for up to 600 bars complete with fibre optic and electrical underwater connectors for up to 4.5 kV and thereby meeting the demands of deep water operations. Bend Restrictors & Bend Stiffeners When making a underwater steel termination to a cable and operating it offshore on a vessel, the way to get the assembly overboard is by using a Cable Overboard Unit (COU) or a cable sheave. This can to some extend introduce a sharp bend of the cable in the joint between the cable and the steel part. The sharp bending of the cable can be minimised by using a bend stiffener or a bend restrictor/Armadillo. The bend restrictor will only allow the cable to bend to a certain angle where it will be stopped mechanically. The bend stiffener will make it more difficult to bend the cable as you have the outer reinforcement either in Neoprene or PUR mounted onto your cable, which will allow more force to be used on the cable before it will bend. The advantage of using either of the two solutions is a longer cable lifetime. PE Mouldings MacArtney provides solutions for terminating underwater cables with a PE jacket to a steel termination by using a special hot moulding machine, where PE moulding material is forced into the moulding form under high pressure. A high pressure moulding to a PE jacketed cable makes sure that the bonding between the cable and steel parts is certified for use at up to 600 bars. Today many cables for deep water use are made with a PE jacket and the possibility of making a watertight connection between without the use of an oil compensated system will reduce the cost. Penetrators MacArtney has a long history of making standard and customer designed penetrators for various solutions in both extreme and more "normal" conditions. A penetrator is build up over a metal part with or without a water-block inside depending on the application. The bonding between the cable and metal parts is done with either a PUR or a PE moulding depending on the cable type. The penetrators can be made with electrical underwater cables, fibre optic underwatercables or a combination of both. A penetrator makes it easy to hook-up equipment without using underwater connectors. The advantage of not using underwater connectors in the system, especially for fibre optic transmissions, is that it will minimise the attenuation loss. Extension & Take Out of Fibre Optic MacArtney A/S has many years of experience in extension of underwater fibre optic and electrical cables. This technology is used were cables are damaged or have to be extended in order to reach new locations. The underwater termination is usually designed to meet the same SWL and depth rating as the cable. Take outs are often used in fibre optic and electrical structural monitoring systems where take outs are needed in several positions on the main cable. Take out and connectors are often designed for a life time of 10 to 15 years in sea water. FITA The FITA (Field Installable Termination Assembly) is designed to be an integral part of a MUX or Umbilical underwater cable termination system. The FITA is field installable without use of any chemicals. Inside the FITA advanced cable and connector booting technology assures functionality even if the FITA are flooded. The FITA is oil compensated with inside bladders that maintains a pressure similar to the outside water environment. The FITA termination is always used in combination with a steel termination where the armor termination assembly is secured to the control system framework using a cone lock system that is designed to the MUX or Umbilical SWL. |
