This data record defines a nonlinear mooring line in the same way as a NLIN data record except that NLID will flag the mooring line as dynamic so that dynamic analysis will be performed for this line unless cable dynamics is switched off by a DOFF data record (see The DYNM/DOFF Data Records - Cable Dynamics ON/OFF Switch).

NLID data records can only be used for elastic catenaries.

Line dynamics is available in all Aqwa programs (except Aqwa-Line), but it has little value in Librium static analysis except to take into account the current drag on mooring lines.

The NLID Data Record

      2   5  7   11    16    21    26    31        41        51        61        71
    - --- -- ---- ----- ----- ----- ----- --------- --------- --------- --------- ---------
   |X|   |  |NLID|     |     |     |     |         |         |        |         |         |
    - --- -- ---- ----- ----- ----- ----- --------- --------- --------- --------- ---------
       |  |   |     |     |     |     |      |          
       |  |   |     |     |     |     |      |           
       |  |   |     |     |     |     |      |_(6) Pretension Tension (F10.0) 
       |  |   |     |     |     |     |
       |  |   |     |     |     |     |_(5) Node Number (I5)
       |  |   |     |     |     |
       |  |   |     |     |     |_(4) Structure Number (I5)
       |  |   |     |     |
       |  |   |     |     |_(3) Node Number (I5)
       |  |   |     |
       |  |   |     |_(2) Structure Number (I5)
       |  |   |
       |  |   |_(1) Data Record Keyword (A4)
       |  |
       |  |_Optional User Identifier (A2)
       |
       |_Compulsory END on last data record in Data Category (A3)

(6) The pretension on the composite cable. The pretension can be defined if either the first or last section of the ECAT data record has defined the required pretension calculation data. Note that the unstretched sectional length is estimated by the quasi-static cable solution excluding the current drag force effect on the cable.