40160431 Cable Route Survey Dictionary

SCIG Information Guide 1 Section : 3Issue : 1

STANDARD DEFINITIONS

‘A’ End : The end of a system, block or repeater, into which the positive (or negative,depending upon local convention) current is usually fed.

‘A’ Terminal : Usually refers to the Terminal supplying positive (or negative, dependingupon local convention) current into the cable system.

Acrylic coating : The protective buffer coating used on optical fibres to protect the glass frommechanical damage.

Aft : Direction towards the stern of a ship.

Alter Course (A/C) : Point along a cable route where the course bearing changes.

Amplifier : Used to boost transmission signals, and inserted at intervals along a cable systemin a watertight housing called a ‘repeater’. See Repeater

Area Slack : See Slack

Armor / Armour wires : Normally galvanised steel wires (of circular cross-section) laidaround the core of the cable, to provide both tensile strength and protection from externaldamage.

Armor / Armoured cable : Cable covered with protective armour wires. Used mainly tominimise the risk of damage to the cable by fishing gear, anchors etc. See Cable Types

Articulated Piping : A system of articulated split pipes which are fitted over the cable to giveadditional protection to that afforded by armoured cables (usually at shore end landings).Articulated pipes are usually applied by divers after the cable has been laid, however sometypes of piping can be applied as the cable is deployed from the vessel.

As Laid List: See Route Position List, Straight Line Diagram (SLD).

Assembly of Submarine Plant : The activity of jointing cable sections and repeaters into acontinuous system length suitable for testing, loading and laying.

Attenuation : The loss of optical or electrical signal strength suffered by a transmissionsignal passing along a fibre (or cable).

Average Ship Slack : See Slack

‘B’ End : The end of a system, block or repeater, into which the positive (or negative,depending upon local convention) current is usually fed.

‘B’ Terminal : Usually refers to the Terminal supplying positive (or negative, dependingupon local convention) current into the cable system.


Beach Anchor : Secure point, usually embedded in the ground to act as a permanent anchorfor the shore end cable.

Beach Clearance : Activity of removing debris from beach to provide a clear corridor forcable and manhole installation. See Ordnance Clearance

Beach Joint : The joint between the land cable and the submarine cable, usually located in thebeach manhole.

Beach Manhole : Concrete vault at the top of the beach landing point used to accommodatethe beach joint. The structure is often used to provide a location for the beach anchor, and forthe storage of extra cable.

Bellmouth : A cable guiding structure which can be shaped in outline like a bell and acts tocontrol the safe bending radius of a cable when it makes a turn. Such structures aresometimes located above cable tanks. The height and design of the bellmouth assists thecable to uncoil freely, in a controlled manner, from the cable tank. Bellmouths can alsoappear at the front of ploughs, and on some tracked vehicles, to guide the cable smoothly intothe burial tool.

Bight : Any U-shaped loop of cable or rope. Often refers to the single U-shaped loop of cablepaid out from the cable ship as a final splice, or to the U-shaped loop of cable exiting thecable tank in which a repeater is positioned.

Block : See Mini System.

Block End Seal : A cable end fitting designed to seal a cable end, which will be laid at sea.Block end seals may be simple fittings to prevent water ingress, or similar to cable jointswhere fibres can be spliced and looped back to allow optical tests, or where the metallicconductor in the cable can be in either open circuit or short circuit with the sea.

Bow: The forward end of a ship.

Branching Unit (BU) : A BU is the sub-sea unit used at the point where the cable systemsplits into two legs or branches.

Burial : Burial of the cable into the seabed for additional protection against external hazards.Burial can be achieved by a number of means including Plough Burial, Jet Burial and Trenchburial.

Burial Assessment Survey (BAS) : A survey of the seabed to determine the likely success ofany type of burial operation and to assist in the appropriate selection of cable armouring.There are different combinations of tools, which may be used to constitute a BAS. Forinstance it may be invasive and continuous, such as a mini-plough or grapnel shaped tool.Alternatively sampling can be carried out at discrete sites, using techniques such as conepenetrometer tests (CPTs), or by core recovery. Other geophysical methods, such asresistivity or seismic refraction can be used, or any combination of the above. – SeeElectronic Burial Assessment (EBAS) and Plough Assessment Survey (PAS).


Burial Depth : The distance between the top of a buried cable and the seafloor. See TrenchDepth

Burial Protection Index : A concept relating depth of burial to the level of protectionachieved taking into account the strength of the material into which the cable is buried. Theobjective of the concept is to provide the optimum economic level of burial protection.

Cable Ship : A vessel usually custom built to install (lay) and repair cables.

Cable Awareness Chart : A chart published and distributed (usually free of charge) showingthe positions of all submarine cables in the area. This information is usually targeted towardsfishermen to avoid cable damage and loss of fishing equipment.

Cable Catenary : Term used to describe the shape of a cable in the water column from theship to the seabed.

Cable Crossing (Buried Cable) : The point at which a cable crosses an existing buried cable.Negotiations with the existing cable owner are required to agree to a mutually acceptablecrossing procedure / methodology for buried cables. There is typically an agreed exclusionzone on each side of the existing cable where no towed bodies such as ploughs or grapnelscan be used. Cable crossing points are usually post lay buried by jetting to ensure that thecable remains in a safe, stable position.

Cable Crossing (Surface Laid) : The point at which a new cable crosses an existing surfacelaid cable. Generally the cable type selected is similar to that already laid underneath.

Cable Crossing ( Pipeline) : See Pipeline Crossing

Cable Data Sheet : Information giving the electrical, optical and mechanical details of thecable. In the case of system cable data the geographical details of the as-laid system areusually given in a standard form known as a Route Position List (RPL), As-Laid Diagram orsplice list.

Cable Depots : Depots strategically placed around the world which store spare cable,repeaters and BU’s suitable for the systems in that area.

Cable Head : Refers to the cable end positioned in the Cable Terminating Cubicle (CTC),Cable Terminating Equipment (CTE) or Power Feed Equipment (PFE).

Cable Pan : A portable cable storage tank.

Cable Route Engineering : The process of planning the build of an undersea cable system.Following the receipt of the ‘cable route survey’ report the final engineered cable route isoptimised and selected. The cable types are selected and the levels of cable slack are definedto allow complete in-fill of the undulating seabed. The end result of the route engineeringprocess is a cable Straight Line Diagram (SLD) which is used to manufacture the cablesystem.

Cable Route Survey : This is the marine survey operation to obtain all the necessaryinformation to design and engineer a cost effective and reliable cable system. Following


receipt of the ‘cable route survey’ report the installation cable route is optimised based on dataobtained on the seabed bathymetery (depth contours etc.), sub-bottom profiling together withother useful information such as side scan sonar, currents, temperatures and prevailingweather conditions. The survey will determine if cable burial is required or indeed ispossible.

Cable Tanks : Large tanks in a ship or depot in which cable is stored.

Cable Terminating Cubicle (CTC) / Cable Terminating Equipment (CTE) : Secure boxor cabinet where the cable end is secured and electrical power applied to the conductive cableelements.

Cable Tonnage : See Lift Capacity

Cable Tracker : A device used to locate and track along submarine cables (surface laid orburied). Usually used in association with an ROV.

Cable Types : The following internationally recognised cable types are offered by a varietyof system suppliers -

RA - Rock Armour Cable, a specialised double armour cable with a very short layouter armour to provide enhanced crush resistance and improved bendingstiffness. Generally used as a surface laid cable where burial is not possible.

DA - Double Armour Cable, based on LW cable with two layers of armourprotection. Can be based on the SA or SAL/LWA cable structure leading tothe terms DAH (heavy) or DAL (light) respectively.

SA - Single Armour Cable, based on LW cable with a single layer of armour wires. Dependant on the number and size of armour wires this type of cable is sometimes referred to as SAH (heavy) or SAM (medium).

LWA / SAL - Light Wire Armour / Single Armour Light Cable, based on LW cablewith a single layer of small diameter armour wires for protection. Generallyused in areas where good burial is expected.

DWP - Deep Water Protected Cable, a special semi - armoured cable design offered asa spare cable for use in deep water where cable abrasion has caused system failures.

LWP / LWS / SPA - Lightweight Protected / Lightweight Screened / SpecialApplication Cable, based on LW cable with a metallic screen and outerpolymeric sheath. Sometimes referred to as Fish-Bite Protection.

LW - Lightweight Cable, used in benign deep water areas.

Chain stopper : Tapered or untapered chain of high strength steel applied in half-hitches tocable. Mainly used on armoured cable during recovery or when the cable under the chainstopper will not be reused.

Coiling : Coiling cable in a tank is usually done in a clockwise direction, with conventionalleft hand lay armour cable. Conventional coiling starts at the outer edge of the tank andworks inwards. In some cases when the inner cone has been reached, the cable is taken out tothe outer edge of the tank and the process is repeated.

Commercial Acceptance : See Ready for Provisional Service (RFPS).


Cone : Structure in the centre of the cable tank. It prevents the cable from being stowed atless than the minimum bending radius and also holds the cable in position.

Cone Penetrometer Test (CPT) : A test carried out on the seabed where a cone is forced intothe seabed material. Data obtained from the force required to penetrate the seabed allows theshear strength or relative density of the material to be determined. CPTs are usually carriedout at discrete locations along the cable route in areas where burial may be considered, andare used to validate the electronic survey data.

Core sample : A cylindrically shaped soil sample taken from the seabed using a core orvibro-core sampling machine.

Corridor : Refers to the width of the sea bed corridor investigated during the surveyoperation. The survey corridor may vary in width dependant on the water depth.See Survey Swathe.

COTDR : Coherent Optical Time Domain Reflectometer. An instrument that is used toperform out of service backscattered light measurements on optically amplified line systems.The functionality is similar to a conventional OTDR instrument; the actual implementationoptimised for long systems. A fibre pair is tested by launching a test signal into the out goingfibre and receiving the scattered light on the in-coming fibre. Light scattered in thetransmission fibre is coupled to the incoming fibre in the loop-back couplers in each amplifierpair in a repeater. In this way a conventional loss versus distance display is obtained for eachoutgoing fibre span on the fibre pair being measured. Coherent optical detection is performedto greatly improve the sensitivity of the instrument.

Crinoline : A movable framework in a cable tank which can be moved up and down torestrict the tendency of cables to whip if the distance from the top of the stow to the bellmouthis too great and payout speed is high.

Cut and Hold Grapnel : A grapnel capable of cutting the cable and then gripping the cableon one side of the cut.

Cutting Drive / Cutting Run : The grappling operation that results in cutting the cable on thebottom of the ocean.

Daily Report : An operational report summarising work completed in the last 24 hours andindicating what work is planed for the next 24 hours.

DC Test Set : Equipment used for resistance and capacitance testing of cables and subseaplant. The equipment is used for routine testing, fault location and integrity testing of cables.

Desk Top Study : This is the first stage of any cable route survey operation. The desk topstudy draws on published information of interest to the cable engineers planning the route andselecting suitable cable types. The desk top study will therefore provide information onclimate, weather patterns, bathymetry, temperatures, shipping, fishing, other cables (both inuse and out of use) etc. along the proposed route.


Deep Water Protected Cable (DWP) : A special design of semi-armoured cable offered as aspare cable for deep water repairs in local areas where non-armoured cable abrasion as provento be a persistent problem due to a rough seabed and high bottom currents. See Cable Types

Depressor : Device fitted to plough or other burial tool which pushes the cable down into thetrench.

Desk Top Study : This is the first stage of any cable route survey operation. The desk topstudy draws on published information of interest to the cable engineers planning the route andselecting suitable cable types. The desk top study will therefore provide information onclimate, weather patterns, bathymetry, temperatures, shipping, fishing, other cables (both inuse and out of use) etc. along the proposed route.

De-Trenching Grapnel : Grapnel used to de-bury (and often recover) buried cable.

Differential Global Positioning System (DGPS) : A satellite based positioning systemwhich makes differential corrections to GPS signals to ensure the most accurate navigationalposition, (accuracy is typically better than ±5 m).

Direct Shore End Landing : Where the main lay vessel can safely approach a landing pointto within a distance where cable can be floated directly ashore.

Directional Drilling : A specialised technique to drill under features without disturbing thelandscape. This technique is used in environmentally sensitive areas where local wildlife orplant life is protected and may be endangered by normal cable installation (excavation)techniques.

Diver Swim Survey : Usually carried out as part of the inshore survey operation. A diverwill swim the cable route to locate and identify any seabed features or obstacles likely tocause problems when the shore end cable is landed.

Double Armour Cable (DA) : Type of cable armouring often used at shore ends consistingof two layers of armour wires. The double layer of armour wires makes this a heavy cablewith enhanced bottom stability and abrasion protection. See Cable Types.

Down Time : Equipment or vessel downtime (i.e. time not operating correctly) is recorded onthe operational daily report

Draw Off & Hold Back (DOHB) Gear : Term applied to the back tensioning equipmentused in conjunction with a cable drum engine. The DOHB gear may be a tracked caterpillarengine or a tire engine capable of traversing across the working width of the drum engine.

Drum Cable Engine : A capstan device for controlling the cable pay out / recovery. Thedrum engine is used in conjunction with a back tensioning unit known as a Draw Off & HoldBack (DOHB) Gear. Cable Drum Engines can be top loading or bottom loading and are fittedwith fleeting knives or rings to control the position of cable on the drum. See Linear CableEngine (LCE).

Duct : A pipe or set of pipes (manufactured from steel, concrete or polymeric material)through which cable can be drawn (pulled). Directionally drilled ducts are often pre-installed


at environmentally sensitive shore end locations where local wildlife or rare plant life couldbe endangered by normal cable installation techniques.

Dynamic Positioning (DP) : Term applied to an integrated computer system used to controlthe propulsion of a vessel. Suitable DP systems allow vessels to automatically maintainstation (position) or to move along a selected route at a given speed.

Elastomer remover / stripper : Equipment used during cable jointing operations to removeelastomer compound surrounding the fibres.

Electrodes (conventional) : Two devices trailed by a repair ship used to detect a tone thathas been applied to a submarine cable from a terminal.

Electrodes (reversed) : Two devices trailed by a repair ship used to inject a tone into asubmarine cable, which is then detected at the terminal.

Electronic Burial Assessment Survey (EBAS) : A burial assessment survey (BAS) whichdoes not depend on a continuous seabed invasive tool like a plough or grapnel (See PloughAssessment Survey). Instead EBAS uses sensors towed along the ground surface, such asresistivity or shear wave sensors, generally coupled with CPT and video/sonar surveillanceequipment. ‘C-BASS’ is an example of an EBAS tool. See BAS, PAS.

Electronic Route Survey : That part of the marine survey in which all data is acquiredelectronically, refers to 3D bathymetry, side scan sonar imagery (a measure of bottomreflectivity, used to identity surface seabed materials) and sub bottom profiling (used to obtaininformation on the composition of the top 2 to 3 metres of seabed material).

Emergency Power Shutdown : Associated with power-feed equipment. Operated in theevent of danger to personnel or cable plant.

Equaliser : Passive device used to achieve nominally flat gain versus wavelength over aspecific transmission band throughout an ocean block within a cable system. Equalisation canbe typically achieved with a Passive Equalisation Unit (PEU) or Gain Equalisation Unit(GEU).

Equalising Strop / Bridle : Length of wire rope used to ‘equalise’ weight between 2stoppers.

Fiber / Fibre Optics : Transmission medium, over glass fibres, employed in moderntelecommunications cable systems utilising pulsed lasers to transmit and receive signals overglass fibers.

Flatfish Grapnel : A grapnel used to cut undersea cables.

Fleeting knives : Machinery operated to keep cable turns in the correct position on a cabledrum engine.

Fleeting rings : Perform same function as fleeting knives.


Freighter Transfer : A means of shipping cable from the cable factory to the cableinstallation vessel by means of a freighter fitted out with cable tanks. This conceptmaximises the main lay cable ship’s time in cable laying and avoids potentially long transitsfor the cable ship.

Fusion splicer : Equipment used to join two fibres together by a process of arc fusion.

Final Splice : Final joint in a cable installation, making the system complete and able tocommence commissioning tests. Also refers to the final joint in a repair operation.

Gifford : A type of grapnel comprising four wide seated hooks at right angles to each other.Used on hard or rough bottoms.

Global Positioning System (GPS) : GPS is a military satellite navigation system, owned andoperated by the United States Department of Defense. The space segment of the systemconsists of 24 satellites, evenly distributed between 6 planes to ensure that a minimum of 4satellites are visible to a receiver anywhere on the earths surface. GPS will therefore providecontinuous, worldwide position fixing. GPS provides a 3-Dimensional high accuracynavigational position, which is deliberately degraded for non military use, (accuracy isvariable and dependant on signal quality, but typically ± 100 m).

Grap Rope : Usually a wire core rope used for towing a grapnel.

Grapnel : A hook like device used on the end of a length of rope to raise the cable to thesurface.

Great Circle : The shortest distance between two points on a spheroid (note that to follow agreat circle exactly requires continual changes of course). See Rhumb Line Distances.

Ground chain : Length of heavy chain between grapnel rope and grapnels to keep front endof grapnel low as grapnels are dragged over the seabed.

Ground rope : Rope attached to cable which lies on the seabed to which buoy moorings areattached. Where a surface buoy is undesirable, it can be used as a grappling tail into whichthe ship can grapple to recover the system cable without damaging it.

Holding Drive / Holding Run : A grappling drive / run to recover cable as opposed to acutting drive / run.

Housing : Term sometimes used for cable joints and repeaters. The housing offers pressureresistance by means of a tubular casing, provides an electrical path for powered systems andprovides the mechanical strength to protect the cable fibres and other components within thehousing.

Hydrodynamic Constant : A convenient measure of the sinking rate of a cable.Hydrodynamic Constant is a function of the cable diameter, drag coefficient and submergedcable weight.

In Line Transition : A change in cable types manufactured on the armouring line in the cablefactory.


Injector Shoe : A jet burial tool fixed to the side of a shore end installation barge, enablingdeep burial (up to 10m) in soft materials in water depths up to 40m.

Instantaneous Ship Slack : See Slack

International Maritime Organisation (IMO) : Responsible for the publication of codes ofsafe working practices and other maritime rules and regulations.

Jet Burial : Cable burial in suitable seabed materials (sands and soft silts/clays only) by anROV or sledge equipped with a jetting tool . Water jets remove seabed material to form atrench into which the cable is lowered, See Trench Burial, Plough Burial.

Joint : The product and the assembly process used to join two cables (perhaps of twodifferent types) to form a continuous segment. The time required to manufacture an opticaljoint is variable and dependant on cable type and the number of fibres.

Jointer : The person who performs the above operation

Jointing : The process of joining two ends of cable together.

Jointless Lay ( Seamless Lay) : A marine operation (lay) which is planned to completionwithout making a shipboard joint.

Lay : Term used to describe the operation of paying out cable to the seabed.

Layback : Horizontal distance from the stern (or cable deployment point) to the position of atowed vehicle or point at which the cable touches the seabed.

Lift capacity (Cable Tonnage) : The weight of cable (normally in tonnes) that a ship is ableto carry.

Lightweight (LW) cable : Generally the cable type used in benign areas of the seabed indeep water. The cable construction is usually one where the inner steel wires (strengthmembers) are surrounded by an insulant of polyethylene.

Lightweight Sheathed Cable : Based on lightweight cable with the addition of an extrapolyethylene sheath coating for additional bending stiffness and abrasion protection.

Lightweight Protected / Lightweight Screened / Special Application Cable : Based onlightweight cable with the addition of a longitudinally continuous (circumferentiallyoverlapped) metallic screen around the core LW cable, and then a final (exterior)polyethylene sheath coating for additional bending stiffness and abrasion protection. Theaddition of a metallic screen has been shown to offer improved protection over abrasion andfish-bite damage.

Light Wire Armour (LWA) / Single Armour Light (SAL) : Type of cable armouringconsisting of a single layer of small diameter armour wires applied over a lightweightstructure. LWA / SAL is generally more flexible than SA, having a lower bending stiffness


and torsional stiffness. Being lighter the LWA / SAL cable characteristics mean that the cablecan be deployed in greater water depths.

Linear Cable Engine (LCE) : Generally situated at the aft end of a cable ship, thisequipment is used to pay out / pick up cable. The equipment consists of two opposing tracksor a series of pairs of wheels and tyres (usually arranged in the vertical plane) which grip thecable. The greater the outboard tension, the more ‘wheel pairs’ are required to grip the cableand control deployment without slippage. See Drum Cable Engine.

Load cell : Instrumentation device incorporating strain gauges configured to measure load.Widely used for measuring cable tension on cable engines and ploughs.

Load / Load Out : Term used to describe the operation of physically taking cable onboardthe vessel (usually from a cable factory).

Main Lay : Refers to the operation where a significant proportion of the cable in a system islaid from a cable ship, as distinct from a ‘separate shore end operation’, ‘post lay burialoperation’ or ‘rock dumping operation’ which tend to use smaller vessels.

Maul : Term used to describe the damage sustained by a cable when it has been hit by towedfishing gear (bottom trawling, otter boards, beam trawls).

Megaripples : These are sedimentary (transverse) bedforms which form at 90 degrees to thedominant current regime and are usually associated with lower current velocities and highsediment supply. Transverse bedforms can be classified as :

Ripples - up to 5cm height, wavelength up to 60cm (usually 5-12 times heightMegaripples - 5cm to 1m height, wavelengths generally >15 times heightSandwaves - >1m height, wavelengths >15 times height (sometimes in excess of 100times height). When the sandwave is mobile, a condition exists where the seabedshifts and may potentially expose previously buried cable.

Mercator : Map projection with straight lines of latitude and longitude at right angles – aconstant bearing is a straight line in Mercator projection. See Universal Transverse Mercator.

Mini System : This is short for “Mini-Repair-System”, an assembly of one or more repeatersand cable joined on the repair ship prior to a repair operation. Such an assembly can enable aspeedy repair if there is reason to believe prior to the operation that such an assembly will beneeded to replace a faulted portion of the system.

Minimum Bending Radius : Cables should be handled and stored to the manufacturer’sspecifications. One important parameter which has to be observed is the cable minimumbending radius which ensures that the cable elements are not over strained or damaged. It isimportant to note that different values of minimum bending radius can apply dependant on thetension in the cable and the time duration of the bend.

Mushroom : A mushroom shaped anchor which comes in various sizes and is used foranchoring buoy moorings, cable ends etc.

NOTS : Abbreviation for ‘Nominal Operating Tensile Strength’ which is a defined cablehandling parameter. It is the maximum tension which can be applied to the cable in


suspension from the ship for 48 hours with a greater than 95 % fibre survival probability forits entire design lifespan.

NPTS : Abbreviation for ‘Nominal Permanent Tensile Strength’ which is a defined cablehandling parameter. It is the maximum tension which can be left permanently in a cable (forits entire designed life span) with greater than 99.9 % fibre survival probability.

NTTS : Abbreviation for ‘Nominal Transient Tensile Strength’ which is a defined cablehandling parameter. It is the maximum tension which can be applied to a cable for one hourwith greater than 95 % fibre survival probability for its entire design lifespan.

Optical Amplifier : An optical amplifier uses Erbium doped fibre and a laser pump toamplify an optical signal. This is done without the optical signal being regenerated byconversion to an electrical signal and then converted back into an optical signal (as is the casewith optical regenerators). Subsea Optical Amplifiers are packaged in housings in a similarmanner to repeaters and continue to be referred to as repeaters.

Ordnance Clearance : Usually undertaken by a specialist team of engineers, qualified tosurvey, detect and dispose of munitions and other abandoned armaments.

OTDR : Optical Time Domain Reflectometer. An instrument which is used to accuratelymeasure the following parameters : fibre length, attenuation per kilometre, splice loss etc.These parameters allow the transmission engineer to access the quality, integrity andsuitability of the fibre.

Out of Use (OOU) Cable (Out of Service Cable) : Term used to describe a cable which isstill in situ on the seabed, but is no longer in commercial transmission service. Some cableswhich fall into this category continue to function in other capacities, for instance in seismicresearch.

Pipeline Crossing : The point at which a cable crosses an existing pipeline. Negotiationswith the pipeline owner are required to agree a mutually acceptable crossing procedure /methodology. It is normal for cables to cross pipelines at 90 degrees and to continue at 90degrees to the pipeline for a distance either side of the pipeline. There is usually an agreedexclusion zone on each side of the pipeline where no towed bodies such as ploughs orgrapnels can be used. Pipeline crossing points are often rock dumped to ensure that the cableremains in a stable position and is not disturbed by fishing activities.

Pipe Tracker : A device used to locate and track along pipelines and cables (surface laid orburied). Usually used in association with an ROV.

Plough / Plow : A tool for burying cable into suitable seabed materials. A plough is a passivedevice that is pulled through the seabed by a ship (usually the cable laying vessel)simultaneously with the vessel laying the cable. The plough is equipped with a share whichcuts a narrow trench in the seabed and then guides the cable into the bottom of the trench.Instrumentation fitted to the plough confirms in real time the burial depth of the cable.Ploughs can be fitted with auxiliary shares to bury larger diameter bodies in the cable such asjoints and repeaters. See ROV.


Plough Assessment Survey (PAS) : A marine survey operation carried to determine thesuitability of the seabed to bury cables. This operation is normally performed by towing asurveyor plough or detrenching grapnel along the proposed cable route and recording datasuch as tow tensions, pitch, roll and depth of burial. See BAS, EBAS

Plough Burial : Burial of the cable into the seabed for enhanced cable protection using aplough (usually towed from the installation vessel as the cable is deployed from the vessel).The cable is guided into the bottom of a narrow trench cut into the seabed by the ploughdepressor . See Jet Burial, Trench Burial.

Plough Tow Tension : Tow force required to pull the plough along the seabed duringploughing operations. The tow force is usually measured at the plough tow point, but can becalculated from the tow tension measured on the ship at the tow winch.

Pock Marks : Most pock marks are formed by the decay of organic matter within thesediment matrix which causes gas to seep upwards and to be released at the seabed asbubbles. The sediment grains in this area are forced apart by the gas and can be winnowedaway by even very low bottom currents. The typical conical shape of pock marks is causedby this winnowing, which is centred around the area of greatest gas release. Pock mark widthand depth can vary greatly, mainly dependent on the level of gas release and bottom currents.Some of the larger pock marks can be tens of metres deep and have very steep side-slopes.The slopes - coupled with the soft sediment - are a direct threat to plough operations.

Post Lay Burial (PLB) : This operation involves the burial of cable into the seabed after thecable has been deployed. The operation can be carried out by divers in shallow water(generally less than 30 m) or by an ROV equipped with jetting or trenching tools.

Post Lay Inspection (PLI) : This operation involves the inspection of the installed cable afterit has been deployed and possibly buried.

Post Lay Inspection & Burial (PLIB) : This operation is usually carried out in areas ofplough burial after the cable installation by an ROV. The inspection operation (usually overselected areas of the buried cable route, up to a maximum percentage of the buried cablelength) confirms the burial depth. If necessary additional burial (usually by jetting) can beimplemented in localised areas, for instance at ‘plough skips’ (where the plough has beenrecovered for repair or maintenance).

Post Lay Rock Dump : Term used to describe the accurate dumping of graded rock over adefined area of the seabed, after cable deployment. This operation is often specified bypipeline owners as part of the cable crossing agreement and is specified to prevent cablemovement over and along the pipeline after installation.

Power Budgets : A tabular listing of optical parameters that in total determine thetransmission performance of the repeatered undersea system. At the top is the idealperformance considering only the intrinsic noise of the optical amplifiers, and then it accountsfor all the possible impairments (e.g., non-linearity of the fibre, manufacturing variations,degrading supervisory effects) to determine the expected beginning of life performance. Itnext list the impairments that can occur over the life of the system (e.g., ageing of repeatersand cable, added loss due to repairs) to determine worst-case end-of-life performance.


Power Feed Equipment (PFE) : A constant current / high voltage power supply used tosupply DC power to a submarine cable system.

Power Safety Officer (PSO) : The person on the cable ship who has responsibility to theCaptain (or Offshore SuperIntendent) for the safety of all personnel on the cable ship withrespect to the voltage and current used during laying and repair operations.

Power Safety Message (PSM) : A message (usually written and faxed, but can be verbal)exchanged between the cable ship and the terminal stations to define who has power safetycontrol and in what condition the cable head is to be maintained.

Pre Lay Rock Dump : Term used to describe the accurate dumping of graded rock over adefined area of the seabed, prior to the cable deployment. This operation is often specified bypipeline owners as part of the cable crossing agreement.

Pre Laid Shore End (Separate Shore End) : Where the main lay vessel cannot safelyapproach the landing point (due to draft, or prevailing weather conditions) a separate shoreend landing operation is carried out using a smaller vessel with a shallow draft allowing for acloser approach to the beach landing. The result is a pre laid shore end, which the main layvessel can recover and carry out an initial splice before laying away.

Pre Lay Grapnel Run (PLGR) : This operation is carried out shortly before burialoperations and involves towing a grapnel along the planned burial route to ensure that anydiscarded material (such as abandoned ropes, fishing equipment etc) which could foul theburial machine and cause cable damage is removed. This activity is separate from ‘RouteClearance’.

Preformed Stoppers : A preformed wire helix, designed to be wrapped around cables andfitted with an eyelet to allow transfer of tension from the cable to another rope withoutdamaging the cable insulation. Can be used in conjunction with both armoured and non-armoured cables.

Protection Grounding Unit (PGU) / Power System Branch Repair Unit (PSBR) :Provides the earth path or ground, in the event the cable is powered, during a repair on asystem that is fitted with Branching Units. It allows the vessel to work on a faulty leg of asystem without loss of traffic on the main leg. Also known as an In Service Repair (ISR) orHot Repair.

Pulse Echo Fault Locator (PEFL) : Sometimes known as a reflectometer. It has beendesigned to locate mismatch conditions (open circuits, short circuits, joints) in cables. Thenature of the mismatch can be ascertained by comparing the reflected pulse with the originaltransmitted pulse.

Ready for Provisional Acceptance (RFPA) : Date on which the System Supplier offers thecable system to the purchaser for acceptance (all main lay marine installation operations,supplier commissioning and acceptance tests having been completed).

Ready For Provisional Service (RFPS) : Date on which the cable system has completed allcommissioning tests / purchaser acceptance tests and has been accepted by the purchaser of


the system, subject to some additional works being carried out. The cable system is ready forcommercial use. (Also known as Commercial Acceptance)

Ready For Service (RFS) : Date on which the cable system has completed all commissioningtests / purchaser acceptance tests and has been accepted by the purchaser of the system. Thecable system is ready for commercial use.

Re Laid : A term used for the relaying or re-routing of a cable system.

Remote Amplifier Box (RAB) : Term used to describe an erbium amplifier housingpositioned in an unrepeatered cable system.

Remotely Operated Vehicle (ROV) : A submersible unmanned vehicle used to inspect, de-bury, bury or re-bury cables. They can also be used to carry out surveys and inspection of thecable on the seabed. ROV’s are usually fitted with cameras, cable tracking equipment and forburial operations can be fitted with a jetting or trenching tool package. See Plough.

Repair : Operation whereby the integrity of a cable system is restored.

Repeater : An element of submersible plant (housing / amplifier) used for boosting thesignal, which is required due to the losses inherent in the transmission media. Repeaters alsotypically contain DC power regulation and supervisory functions.

Repeatered Cable System : A powered cable system fitted with repeaters (or opticalamplifiers).

Request for Quotation (RFQ) : Request sent to specialist sub-contractors to supply aquotation for work specified in an attached scope of work.

Rhumb Line Distance : The constant bearing distance between two points on a spheroid.See Great Circle

Ripples : See Megaripples.

Rock Armour (RA) Cable : A special type of double armoured cable. The outer layer ofarmour wires will have a very short lay length to provide enhanced crush resistance and henceprovide improved protection against external damage caused by impacts from rocks, droppedobjects and towed equipment such as fishing gear. See Cable Types.

Rotometer (Roto) : An instrument used on ships for measuring the movement of cable. Therotometer is usually a wheel which runs on the cable to measure the length and speed atwhich cable is loaded, paid out or picked up.

Route Clearance : A Pre Lay Grapnel Run, where specific out of service cables are targetedfor removal from the cable route. Identified cables are recovered or cut back to provide aclear corridor for the installation for the new cable system.

Route Engineering Study : An enhanced Desk Top Study which involves visiting thelanding sites and gathering additional local information.


Route Position List (RPL) : A standard format for providing information on the planned andthen as laid positions of the cable system. Details on the cable type, sectional and cumulativecable length, positions of alter courses, joint housings, repeaters, and cable slack values arerecorded.

Route Survey : See Cable Route Survey

Sand Waves : When mobile, a condition exists where the seabed shifts and may potentiallyexpose previously buried cable. See Megaripples

Scientific Cable : Cables used for research purposes and not for commercialtelecommunications, this may include out of service cables which have been donated or soldto an academic institution. Some scientific cables are used as part of the World Wide OceanCirculation Experiment (WWOCE) to measure ocean currents and their effect on climatechange, predictions and modelling.

Seabed Slack : See Slack

Siemens Stopper : A platted wire rope stopper applied to armoured cables. Functions in asimilar manner as pre formed stoppers.

Separate Shore End : See Pre Laid Shore End

Share : Part of the plough which engages in the seabed to bury the cable. See Depressor

Ships Slack : See Slack

Side Scan Sonar : An acoustic technique to map the reflectivity of seabed materialidentifying potential obstructions on the seabed . Used primarily during survey operationsprior to ploughing operations. The use of side scan sonar is helpful in cable repair operationsin identifying surface laid cables and in localising fault locations.

Single Armour (SA) Cable : Type of cable armouring consisting of a single layer of armourwires applied over a lightweight cable structure. Depending on the diameter of the armourwires used for protection some suppliers use the terms Single Armour Medium (SAM) andSingle Armour Heavy (SAH). See Cable Types.

Single Armour Light (SAL) / Light Wire Armour (LWA) Cable : Type of cablearmouring consisting of a single layer of smaller diameter armour wires applied over alightweight cable structure. SAL is generally more flexible than SA, having a lower bendingstiffness and torsional stiffness. Being lighter the SAL cable characteristics mean that thecable can be deployed in greater water depths. See Cable Types.

Skid : The parts of the plough which run along the seabed are called skids. The function of askid is to support the weight of the plough, while allowing the plough to ride over ruggedterrain.

Slack : The term ‘Slack’ defines a ratio of excess cable length to distance, but there areseveral different precise definitions given below, all of which are important in cable-work.Slack values are usually expressed as a percentage:


Area Slack = (‘Planned Cable length on seabed between waypoints’ - ‘route distanceat sea level between waypoints’) / ‘route distance at sea level between waypoints’Area slack is the figure generally quoted on the route position list of a planned lay, andis used for defining the cable lengths to be manufactured.Average Ship Slack = (‘Cable length overboarded from ship between two points’ –‘route distance at sea level between the points’) / ‘route distance at sea level betweenthe points’Average Ship Slack is typically quoted on an ‘as laid RPL’ that forms part of thenormal lay report.Instantaneous Ship Slack = (‘Cable Payout Speed’ – ‘Ship Speed’) / ‘Ship Speed’Seabed Slack = (‘Incremental Length of Cable on Seabed’ – ‘Increment of Lengthmeasured along the seabed’) / ‘Increment of Length measured along the seabed’

Spear Point grapnel : A type of grapnel used in softer seabeds to achieve greater penetrationfor cable recovery.

Special Application (SPA) / Lightweight Protected / Lightweight Screened Cable : Isbased on lightweight cable with the addition of a longitudinally continuous (circumferentiallyoverlapped) metallic screen around the core LW cable, and then a final (exterior)polyethylene sheath coating for additional bending stiffness and abrasion protection. Theaddition of a metallic screen has been shown to offer improved protection over abrasion andfish-bite damage. See Cable Types.

Spheroid : The assumed shape of the earth, WGS84 datum (World Geodetic System 1984) isnormally used.

Straight Line Diagram (SLD) : The SLD is the result of the cable engineering processcarried out after the cable route survey. The SLD provides information on the cable types andlengths required to make the system, together with a manufacturing tolerance and identifyingcritical areas of cable which are required to be accurately positioned (for pipeline crossingsetc.) in the system. Repeater positions (and separations) are usually indicated in the SLD,together with plough up and down positions, water depths and slack allocations.

Stern : The aft part of a ship.

Stinger : A rigid share supported from a shore end barge which is fitted with water jettingnozzles and capable of deep burial of cables (up to 5 m burial) in suitable seabed materials.

Stow : A term to describe the stowage of cable in a cable tank.

Stowage Factor : A term indicating the volume occupied by a known length of cable.

Strumming : A term used to describe the standing wave vibration set up in unsupported cableduring deployment or when in suspension between localised high spots on the seabed.Strumming is induced by the drag forces generated when water currents flow across the cablein suspension.

Sub Bottom Profiling (SBP) : This is an acoustic method of determining the verticallithological distribution of the upper seabed. SBP equipment releases quite low power, high


frequency, short pulses of acoustic energy into the water column and measures energyreflected back from the seabed and sub-seabed.

The acoustic energy reflects back not only from the seabed surface, but also from layerswithin the seabed, because of differing physical properties associated with differentgeological units.

Surface Lay : Operation where cable is paid out from the vessel and laid directly onto theseabed without being buried.

Suspension : A term used to describe cable in free span, i.e. an unsupported length of cableheld in a catenary by the residual cable tension at each side of the suspension. Cable insuspension can suffer damage at the contact points where abrasion can occur (chafe) and maybe subject to strumming, a cable vibration induced by the flow of water across the cablesuspension.

Swathe : Refers to a survey swathe or width of the survey corridor.

System Load and Lay Instructions (SLLI) / Handling Guidelines : A document preparedby the system manufacturer for the marine installer detailing how the cable system (includingjoints and repeaters) will be loaded, laid and handled safely. Instructions on the equipmentand services to be provided and the required safety standards to be maintained during theoperation are defined. A project plan is included.

Trailed Electrode : See Electrodes

Transition : The length of cable (or body) between two different cable types.

Transponder : An acoustic beacon which relays positional information (bearing anddistance) to a hydrophone receiver (usually hull mounted) on the surface vessel.Transponders can be used to locate subsea equipment such as ploughs, ROV’s etc., to mark atarget area on the seabed or to ensure accurate placement of equipment on the sea bottom.

Trench Burial : Cable burial in the seabed achieved by a mechanical cutter such as a chaincutter or a rock wheel cutter. This technique is typically used where plough burial cannotachieve adequate protection. See Jet Burial, Plough Burial.

Trench Depth : The distance between the bottom of the cut trench and the seafloor (SeeBurial Depth)

Turn Over : Process of moving cable from one tank to another to facilitate jointing,inspection/restowing or assembly of a larger system.

UTS : Abbreviation for the Ultimate Tensile Strength which a cable can support beforemechanical failure.

Under running : Under running is the process of passing a cable over an under runningsheave to allow the vessel to move towards a fault location or cable end. This processbecomes necessary to reduce the amount of cable removed during a repair when grappling hasoccurred some distance from the fault.


Universal Joint / Universal Coupling (UJ / UC) : A type of cable jointing and repeatercoupling that uses an agreed set of equipment and tooling for assembly, and has beenapproved using an international standard for qualification testing.

Universal Quick Joint : A type of cable jointing for non-repeatered systems, that uses anagreed set of equipment and tooling for assembly and uses an international standard forqualification testing.

Universal Transverse Mercator (UTM) : Grid system in which the world is divided into 60zones, each consisting of 6 degrees of longitude. Latitude and longitude may be convertedinto grid terms and vice versa using the appropriate formulae.

Unrepeatered Cable System : An un-powered cable system, without repeaters. The cable iscapable of carrying a small current and voltage to monitor Insulation Resistance for a faultcondition.

V Sheave : Type of grooved bow or stern roller sheave used as a cable guide.

Waypoints : Discrete locations along a cable route where special events occur, i.e. coursechanges.

WDM : Wavelength Division Multiplexing. A method of transmitting optical signals atseveral wavelengths over the same fibre at the same time.

Whiskers : A guide manufactured from shaped steel plate forming a three dimensionalstructure used to guide cables into and out of the vessel over a roller sheave so that the cableminimum bend radius is controlled.

Whiting Chalk : A chalk applied to armoured cables to prevent cables sticking together whenseepage of the armour compounds may occur in hot storage conditions.

Wire pennant : Length of wire used to hand off cables and ropes when transferring them toand from cable drums.

Wrap / Coil : Term used to describe the coiling and storage of fibres inside a joint housing.

X Rays : A process used to detect defects such as voids, inclusions and non-concentricityoccurring in moulded joints during cable repair operations.

Yale Grips : A custom made webbing stopper for use on rope and armoured cable.

Documents

40160431 Cable Route Survey Dictionary