NaviPac Cable Laying Utilities Author : Ole Kristensen Company : EIVA a/s Date: April 2012
NaviPac Cable laying Page 2 Introduction This document gives a short introduction to the catenary functions (for cable and pipe laying) found in NaviPac as it is and lists a series of ideas for improvement of the functionality Contents NaviPac Cable Laying Utilities... 1 Revision table... 2 1 NaviPac 3.8... 2 1.1 Cable over length... 2 1.1.1 Definition in HD... 4 1.2 Barge run-lines... 7 1.3 Catenary monitoring... 10 1.4 Interface to CMS... 12 2 Next generation... 12 2.1 NaviCat... 13 2.2 Cable Lay... 15 2.3 3D Display... 15 Revision table Date Who Comment 10-5-2004 OKR Document created 22-9-2004 OKR Added section 2.2 26-4-2012 OKR Upgraded to version 3.8 More details on HD control 1 NaviPac 3.8 The actual NaviPac version includes a series of functions, which might be used during cable or pipe laying jobs. Most of these have been designed in close cooperation with various clients using these features for laying jobs over the last years. 1.1 Cable over length A typical scenario in laying a cable is that you end up having more cable than the remaining line to avoid cutting the cable; a term called Cable over length is introduced. Following a set of rules, a new run-line is created to obtain the wanted length. File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 2
NaviPac Cable laying Page 3 A run-line is defined with a total length of 1248 meters. But the remaining cable is 1275 meters ie. Adding 27 meters in total. Inserting an overlength route may now change each segment: The operator may define route criteria and monitor the changes before accepting them. with the result showed graphically: File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 3
NaviPac Cable laying Page 4 1.1.1 Definition in HD To activate the feature just follow the steps in Helmsman s Display: Edit the runline; in page Segments double click (edit) a STRAIGHT segment (probably the last (or first) segment); select Main page; select Wave Route (overlength) option and the overlength dialog will pop up. From here on it s just a step-by-step procedure. File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 4
NaviPac Cable laying Page 5 File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 5
NaviPac Cable laying Page 6 File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 6
NaviPac Cable laying Page 7 1.2 Barge run-lines To obtain the best possible laying operation especially in the so-called S laying mode the touch down point (where the cable/pipe hits the bottom) is a certain distance behind the laying barge. Before a job is started, the system is fed with the planned route which can be used as runlines in the helmsman s Display. But with a layback touch down point there a difference between the planned route and the route to be followed by the barge. File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 7
NaviPac Cable laying Page 8 NaviPac offers a tool called Barge run-lines, where we based on planned route and layback determines the actual line. HD with display of planned route File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 8
NaviPac Cable laying Page 9 HD with graphical result shown. File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 9
NaviPac Cable laying Page 10 1.3 Catenary monitoring During the laying process, a very important factor is monitoring the total amount of cable out (in the water column), the tension in the cable and how much the cable is bending. NaviPac offers a simple catenary monitoring tool which based on the winch point (where the cable leaves the barge) and the touch down point (where the cable hit s the seabed monitored with ROV or similar). It done by defining two objects in NaviPac one for the leaving point (typically an offset on the vessel) and one for the touch down point: A catenary monitoring (up to 5 simultaneously) may now be defined: File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 10
NaviPac Cable laying Page 11 Definition of calculations: - Name - Input parameters - Leave point - Touch down point The optimal calculation is obtained by inputting weight of catenary cable. The result may be monitored (any computer on the network) as alphanumerical displays: The most interesting value to watch for the operator is normally the Vertical Angle (Theta) that is the angle of the catenary curve. Horizontal Distance (X): File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 11
NaviPac Cable laying Page 12 This field gives the horizontal distance between the two points. Vertical Distance (Y): This field gives the vertical distance between the two points. Vertical Angle (Theta): Hold the vertical angle of the catenary curve. Length of Catenary (L): Hold the computed length of the catenary curve. Min radius of catenary curve : The computed min. radius of the catenary curve Horizontal Tension (H): If a unit weight is specified the horizontal tension is shown here. Vertical Tension (V): If a unit weight is specified the vertical tension is shown here. Total Tension (T): If a unit weight is specified the sum of vertical and horizontal tension is shown here. 1.4 Interface to CMS NaviPac includes, if operated in TMS/RigMove mode, an interface to a special Stolt Offshore Catenary Monitoring System (Halliburton Subsea CMS ) It output s information about barge and anchor locations, and offers the receiving program sufficient information to document behavior of the anchor chains. Details on formats can be obtained from NaviPac manuals. 2 Next generation During the use of NaviPac for barge and laying operations, and lot of new ideas has been raised from a.o. Subsea7, C&C Technology and Capital Signal, and we are based on these input s working of projects to include these ideas in standard NaviPac operations. This has resulted in a CableLay add-on to NaviPac developed in cooperation with the Danish company JD Contractors. C/B Henry P. Lading File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 12
NaviPac Cable laying Page 13 The system is build around NaviPac, as all sensor interfacing and recording takes place here. The system requires special data input of - Cable output angle - Cable length - Cable tension Based on those inputs the system calculates the catenary curve in the water and estimates the touchdown point. Please note that cable interfacing is most often different for each vessel, so tailor-making must be expected! 2.1 NaviCat The brain in the system is the EIVA catenary solution, which performs a full 3D calculation of the cable in the water column and along the seabed. File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 13
NaviPac Cable laying Page 14 The catenary model is based on a 3D particle system and allows full computation of forces along the chain. This model can be expanded to include external forces such as current. The system loads terrain information (DTM, profile or fixed depth) and used this for the touchdown estimation and cable curvature calculations. File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 14
NaviPac Cable laying Page 15 2.2 Cable Lay The Cable Lay module is program running beside NaviPac (same pc or remote) and it gives the cable operator the needed displays to monitor cable speed, angle, bending radius etc. This module is also responsible for the cable amounting, and thus a very important tool. 2.3 3D Display The cable lay scenario can be connected to NaviPac Online3D, and thus give a user friendly visualization of the entire project: File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 15
NaviPac Cable laying Page 16 File: C:\USERS\LDA\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.OUTLOOK\5F6ADPH2\CABLELAYING.DOC Page 16