Problems including a MoorDyn file in my Fast model

Greetings,

I’m trying to include a mooring system based on a single vertical cable on my OpenFAST model, through a MoorDyn input file.

Currently my MoorDyn file looks like this: (WtrDepth is 200 and the lowest point of mmy strcutre is set at -100, 0, -15)

--------------------- MoorDyn Input File ------------------------------------
Mooring system for MIT/NREL TLP 
True    Echo      - Echo the input to "<rootname>.MD.ech"?  (flag)
----------------------- LINE TYPES ------------------------------------------
Name     Diam      MassDen       EA    BA/-zeta    EI    Cd      Ca     CdAx   CaAx
(-)       (m)      (kg/m)        (N)    (N-s/-)    (-)   (-)     (-)    (-)    (-)
main     1    116.027       9.99E19    659733900000     0.0   1.6     1.0    0.1    0.0
---------------------- POINTS --------------------------------                                           
ID     Attachment  X        Y         Z      M      V       CdA   CA
(-)    (-)        (m)      (m)       (m)    (kg)   (m^3)   (m^2)  (-)
1      fixed	-100.0      0    -200.0     0      0        0     0
2      vessel	-100.0      0.0     -15    0      0        0     0
---------------------- LINES --------------------------------------                                           
ID      LineType   AttachA   AttachB  UnstrLen  NumSegs   Outputs
(-)       (-)        (-)       (-)       (m)      (-)       (-)
1         main        1         2      185	10        -
---------------------- SOLVER OPTIONS ---------------------------------------
0.001    dtM       - time step to use in mooring integration (s)
3.0e4    kbot      - bottom stiffness (Pa/m)
3.0e4    cbot      - bottom damping (Pa-s/m)
2.0      dtIC      - time interval for analyzing convergence during IC gen (s)
60.0     TmaxIC    - max time for ic gen (s)
4.0      CdScaleIC - factor by which to scale drag coefficients during dynamic relaxation (-)
0.01     threshIC  - threshold for IC convergence (-)
------------------------ OUTPUTS --------------------------------------------
FairTen1
AnchTen1
END
------------------------- need this line --------------------------------------

I’m getting this erro upon compiling:

Running MoorDyn (v2.a27, 2022-07-20).
   This is an alpha version of MoorDyn-F v2, with significant input file changes from v1.
   Copyright: (C) 2021 National Renewable Energy Laboratory, (C) 2019 Matt Hall
   Parsing MoorDyn input file: .\IEA-15-240-RWT-Monopile_MoorDyn.dat
   Created mooring system:  1 lines, 2 points, 0 rods, 0 bodies.
   Finalizing initial conditions using dynamic relaxation.

 Warning: extreme pitch moment from body-attached Point            1
 Warning: extreme pitch moment from body-attached Point            1
 Warning: extreme pitch moment from body-attached Point            1
 Warning: extreme pitch moment from body-attached Point            1
 Warning: extreme pitch moment from body-attached Point            1
 Warning: extreme pitch moment from body-attached Point            1
 Warning: extreme pitch moment from body-attached Point            1
 NaN detected at time   4.000000000000000E-003  in Line            1  in MoorDyn
 .
 NaN detected at time   4.500000000000001E-003  in Line            1  in MoorDyn
 .
   t=5.00000E-03  FairTen 1: NaN, 1, 2
 NaN detected at time   5.000000000000000E-003  in Line            1  in MoorDyn
 .
 NaN detected at time   5.500000000000000E-003  in Line            1  in MoorDyn
 .
   t=6.00000E-03  FairTen 1: NaN, NaN, 1
 NaN detected at time   6.000000000000000E-003  in Line            1  in MoorDyn
 .
 NaN detected at time   6.500000000000001E-003  in Line            1  in MoorDyn
 .
   t=7.00000E-03  FairTen 1: NaN, NaN, NaN
 NaN detected at time   7.000000000000000E-003  in Line            1  in MoorDyn
 .
 NaN detected at time   7.500000000000000E-003  in Line            1  in MoorDyn
 .
   t=8.00000E-03  FairTen 1: NaN, NaN, NaN
 NaN detected at time   8.000000000000000E-003  in Line            1  in MoorDyn
 .
 NaN detected at time   8.500000000000001E-003  in Line            1  in MoorDyn
 .
   t=9.00000E-03  FairTen 1: NaN, NaN, NaN
 NaN detected at time   9.000000000000001E-003  in Line            1  in MoorDyn
 .
 NaN detected at time   9.500000000000001E-003  in Line            1  in MoorDyn
 .
   t=1.00000E-02  FairTen 1: NaN, NaN, NaN
 NaN detected at time   1.000000000000000E-002  in Line            1  in MoorDyn
 .
 NaN detected at time   1.050000000000000E-002  in Line            1  in MoorDyn
 .
   t=1.10000E-02  FairTen 1: NaN, NaN, NaN
 NaN detected at time   1.100000000000000E-002  in Line            1  in MoorDyn
 .
 NaN detected at time   1.150000000000000E-002  in Line            1  in MoorDyn
 .
   t=1.20000E-02  FairTen 1: NaN, NaN, NaN
 NaN detected at time   1.200000000000000E-002  in Line            1  in MoorDyn
 .
 NaN detected at time   1.250000000000000E-002  in Line            1  in MoorDyn
 .
   t=1.30000E-02  FairTen 1: NaN, NaN, NaN
 NaN detected at time   1.300000000000000E-002  in Line            1  in MoorDyn
 .
 NaN detected at time   1.350000000000001E-002  in Line            1  in MoorDyn
 .
   t=1.40000E-02  FairTen 1: NaN, NaN, NaN
   Fairlead tensions converged to 1% after 1.40000E-02 seconds.
   MoorDyn initialization completed.

FAST_InitializeAll:FAST_Init:FAST_ReadPrimaryFile:1/VTK_fps is not an integer multiple of DT.
FAST will output VTK information at 15.385 fps, the closest rate possible.
FAST_InitializeAll: NaN state detected.

 OpenFAST encountered an error during module initialization.
 Simulation error level: FATAL ERROR

I think that the error is not due to my MoorDyn file but rather something related to the rest of my model. I am not able to find out what exactly. Eventhough I have Echo enabled, I don’t get any .ech file from MoorDyn…

What could cause this error? Thanks!

Dear @Pere.Palacin,

My guess is the big problem is that your EA stiffness is unrealistically high (10^19 N) causing problems in the numerical solve.

Best regards,

Dear @Jason.Jonkman ,

Thanks a lot for your reply. That fixed the error indeed. I was having problems with the default value so I kept on increasing it as I thought that was the problem.

Currently I am facing a new problem as I get this error upon compiling:


FAST_Solution:CalcOutputs_And_SolveForInputs:SolveOption1:FullOpt1_InputOutputSolve:HydroDyn_CalcO
utput:Morison_CalcOutput:The upper end-plate of a member must not cross the water plane.  This is
not true for Member ID 2
Morison_CalcOutput:The lowest element of a Morison member has become partially submerged!  This
is not allowed.  Please review your model and create a discretization such that even with
displacements, the lowest element of a member does not become partially submerged.
HydroDyn_CalcOutput:Morison_CalcOutput:The upper end-plate of a member must not cross the water
plane.  This is not true for Member ID 2
Morison_CalcOutput:The lowest element of a Morison member has become partially submerged!  This
is not allowed.  Please review your model and create a discretization such that even with
displacements, the lowest element of a member does not become partially submerged.

 OpenFAST encountered an error at simulation time 1.85 of 30 seconds.
 Simulation error level: FATAL ERROR

The VTK visualization reveals that the platform is sinking. Which means that I must fix it’s buoyancy. How can I tweak the buoyancy of the Platform? I don’t see any way to fix it in my HydroDyn file other than increase the volume of water displaced by the floater…

Please find attached a sample of my HydroDyn file.

Thanks

------- HydroDyn v2.03.* Input File --------------------------------------------
IEA 15 MW offshore reference model monopile configuration
False            Echo           - Echo the input file data (flag)
---------------------- ENVIRONMENTAL CONDITIONS --------------------------------
        "default"   WtrDens        - Water density (kg/m^3)
        "default"   WtrDpth        - Water depth (meters)
        "default"   MSL2SWL        - Offset between still-water level and mean sea level (meters) [positive upward; unused when WaveMod = 6; must be zero if PotMod=1 or 2]
---------------------- WAVES ---------------------------------------------------
             0   WaveMod        - Incident wave kinematics model {0: none=still water, 1: regular (periodic), 1P#: regular with user-specified phase, 2: JONSWAP/Pierson-Moskowitz spectrum (irregular), 3: White noise spectrum (irregular), 4: user-defined spectrum from routine UserWaveSpctrm (irregular), 5: Externally generated wave-elevation time series, 6: Externally generated full wave-kinematics time series [option 6 is invalid for PotMod/=0]} (switch)
             0   WaveStMod      - Model for stretching incident wave kinematics to instantaneous free surface {0: none=no stretching, 1: vertical stretching, 2: extrapolation stretching, 3: Wheeler stretching} (switch) [unused when WaveMod=0 or when PotMod/=0]
          3630   WaveTMax       - Analysis time for incident wave calculations (sec) [unused when WaveMod=0; determines WaveDOmega=2Pi/WaveTMax in the IFFT]
          0.25   WaveDT         - Time step for incident wave calculations     (sec) [unused when WaveMod=0; 0.1<=WaveDT<=1.0 recommended; determines WaveOmegaMax=Pi/WaveDT in the IFFT]
          4.52   WaveHs         - Significant wave height of incident waves (meters) [used only when WaveMod=1, 2, or 3]
          9.45   WaveTp         - Peak-spectral period of incident waves       (sec) [used only when WaveMod=1 or 2]
"DEFAULT"        WavePkShp      - Peak-shape parameter of incident wave spectrum (-) or DEFAULT (string) [used only when WaveMod=2; use 1.0 for Pierson-Moskowitz]
       0.15708   WvLowCOff      - Low  cut-off frequency or lower frequency limit of the wave spectrum beyond which the wave spectrum is zeroed (rad/s) [unused when WaveMod=0, 1, or 6]
           3.2   WvHiCOff       - High cut-off frequency or upper frequency limit of the wave spectrum beyond which the wave spectrum is zeroed (rad/s) [unused when WaveMod=0, 1, or 6]
             0   WaveDir        - Incident wave propagation heading direction                         (degrees) [unused when WaveMod=0 or 6]
             0   WaveDirMod     - Directional spreading function {0: none, 1: COS2S}                  (-)       [only used when WaveMod=2,3, or 4]
             1   WaveDirSpread  - Wave direction spreading coefficient ( > 0 )                        (-)       [only used when WaveMod=2,3, or 4 and WaveDirMod=1]
             1   WaveNDir       - Number of wave directions                                           (-)       [only used when WaveMod=2,3, or 4 and WaveDirMod=1; odd number only]
            90   WaveDirRange   - Range of wave directions (full range: WaveDir +/- 1/2*WaveDirRange) (degrees) [only used when WaveMod=2,3,or 4 and WaveDirMod=1]
     123456789   WaveSeed(1)    - First  random seed of incident waves [-2147483648 to 2147483647]    (-)       [unused when WaveMod=0, 5, or 6]
      RANLUX     WaveSeed(2)    - Second random seed of incident waves [-2147483648 to 2147483647]    (-)       [unused when WaveMod=0, 5, or 6] 
TRUE             WaveNDAmp      - Flag for normally distributed amplitudes                            (flag)    [only used when WaveMod=2, 3, or 4]
""               WvKinFile      - Root name of externally generated wave data file(s)        (quoted string)    [used only when WaveMod=5 or 6]
             1   NWaveElev      - Number of points where the incident wave elevations can be computed (-)       [maximum of 9 output locations]
             0   WaveElevxi     - List of xi-coordinates for points where the incident wave elevations can be output (meters) [NWaveElev points, separated by commas or white space; usused if NWaveElev = 0]
             0   WaveElevyi     - List of yi-coordinates for points where the incident wave elevations can be output (meters) [NWaveElev points, separated by commas or white space; usused if NWaveElev = 0]
---------------------- 2ND-ORDER WAVES ----------------------------------------- [unused with WaveMod=0 or 6]
False            WvDiffQTF      - Full difference-frequency 2nd-order wave kinematics (flag)
False            WvSumQTF       - Full summation-frequency  2nd-order wave kinematics (flag)
             0   WvLowCOffD     - Low  frequency cutoff used in the difference-frequencies (rad/s) [Only used with a difference-frequency method]
       3.04292   WvHiCOffD      - High frequency cutoff used in the difference-frequencies (rad/s) [Only used with a difference-frequency method]
      0.314159   WvLowCOffS     - Low  frequency cutoff used in the summation-frequencies  (rad/s) [Only used with a summation-frequency  method]
           3.2   WvHiCOffS      - High frequency cutoff used in the summation-frequencies  (rad/s) [Only used with a summation-frequency  method]
---------------------- CURRENT ------------------------------------------------- [unused with WaveMod=6]
             1   CurrMod        - Current profile model {0: none=no current, 1: standard, 2: user-defined from routine UserCurrent} (switch)
             2   CurrSSV0       - Sub-surface current velocity at still water level  (m/s) [used only when CurrMod=1]
            90        CurrSSDir      - Sub-surface current heading direction (degrees) or DEFAULT (string) [used only when CurrMod=1]
            5   CurrNSRef      - Near-surface current reference depth            (meters) [used only when CurrMod=1]
             2   CurrNSV0       - Near-surface current velocity at still water level (m/s) [used only when CurrMod=1]
             90   CurrNSDir      - Near-surface current heading direction         (degrees) [used only when CurrMod=1]
             2   CurrDIV        - Depth-independent current velocity                 (m/s) [used only when CurrMod=1]
             90   CurrDIDir      - Depth-independent current heading direction    (degrees) [used only when CurrMod=1]
---------------------- FLOATING PLATFORM --------------------------------------- [unused with WaveMod=6]
             0   PotMod         - Potential-flow model {0: none=no potential flow, 1: frequency-to-time-domain transforms based on WAMIT output, 2: fluid-impulse theory (FIT)} (switch)
	     0   ExctnMod       - Wave Excitation model {0: None, 1: DFT, 2: state-space} (switch) [only used when PotMod=1; STATE-SPACE REQUIRES *.ssexctn INPUT FILE]
	     0   RdtnMod        - Radiation memory-effect model {0: no memory-effect calculation, 1: convolution, 2: state-space} (switch) [only used when PotMod=1; STATE-SPACE REQUIRES *.ss INPUT FILE]
	   60.0  RdtnTMax       - Analysis time for wave radiation kernel calculations (sec) [only used when PotMod=1; determines RdtnDOmega=Pi/RdtnTMax in the cosine transform; MAKE SURE THIS IS LONG ENOUGH FOR THE RADIATION IMPULSE RESPONSE FUNCTIONS TO DECAY TO NEAR-ZERO FOR THE GIVEN PLATFORM!]
	   0   RdtnDT         - Time step for wave radiation kernel calculations (sec) [only used when PotMod=1; DT<=RdtnDT<=0.1 recommended; determines RdtnOmegaMax=Pi/RdtnDT in the cosine transform]
	     1   NBody          - Number of WAMIT bodies to be used (-) [>=1; only used when PotMod=1. If NBodyMod=1, the WAMIT data contains a vector of size 6*NBody x 1 and matrices of size 6*NBody x 6*NBody; if NBodyMod>1, there are NBody sets of WAMIT data each with a vector of size 6 x 1 and matrices of size 6 x 6]
	     1   NBodyMod       - Body coupling model {1: include coupling terms between each body and NBody in HydroDyn equals NBODY in WAMIT, 2: neglect coupling terms between each body and NBODY=1 with XBODY=0 in WAMIT, 3: Neglect coupling terms between each body and NBODY=1 with XBODY=/0 in WAMIT} (switch) [only used when PotMod=1]
"unused"         PotFile        - Root name of potential-flow model data; WAMIT output files containing the linear, nondimensionalized, hydrostatic restoring matrix (.hst), frequency-dependent hydrodynamic added mass matrix and damping matrix (.1), and frequency- and direction-dependent wave excitation force vector per unit wave amplitude (.3) (quoted string) [MAKE SURE THE FREQUENCIES INHERENT IN THESE WAMIT FILES SPAN THE PHYSICALLY-SIGNIFICANT RANGE OF FREQUENCIES FOR THE GIVEN PLATFORM; THEY MUST CONTAIN THE ZERO- AND INFINITE-FREQUENCY LIMITS!]
             1   WAMITULEN      - Characteristic body length scale used to redimensionalize WAMIT output (meters) [only used when PotMod=1]
	   0.0   PtfmRefxt      - The xt offset of the body reference point(s) from (0,0,0) (meters) [1 to NBody] [only used when PotMod=1]
	   0.0   PtfmRefyt      - The yt offset of the body reference point(s) from (0,0,0) (meters) [1 to NBody] [only used when PotMod=1]
	   0.0   PtfmRefzt      - The zt offset of the body reference point(s) from (0,0,0) (meters) [1 to NBody] [only used when PotMod=1. If NBodyMod=2,PtfmRefzt=0.0]
	   0.0   PtfmRefztRot    - The rotation about zt of the body reference frame(s) from xt/yt (degrees) [1 to NBody] [only used when PotMod=1]
	   0.0   PtfmVol0       - Displaced volume of water when the platform is in its undisplaced position (m^3) [only used when PotMod=1; USE THE SAME VALUE COMPUTED BY WAMIT AS OUTPUT IN THE .OUT FILE!]
           0.0   PtfmCOBxt      - The xt offset of the center of buoyancy (COB) from the platform reference point (meters)  [only used when PotMod=1]
           0.0   PtfmCOByt      - The yt offset of the center of buoyancy (COB) from the platform reference point (meters)  [only used when PotMod=1]
---------------------- 2ND-ORDER FLOATING PLATFORM FORCES ---------------------- [unused with WaveMod=0 or 6, or PotMod=0 or 2]
             0   MnDrift        - Mean-drift 2nd-order forces computed                                       {0: None; [7, 8, 9, 10, 11, or 12]: WAMIT file to use} [Only one of MnDrift, NewmanApp, or DiffQTF can be non-zero]
             0   NewmanApp      - Mean- and slow-drift 2nd-order forces computed with Newman's approximation {0: None; [7, 8, 9, 10, 11, or 12]: WAMIT file to use} [Only one of MnDrift, NewmanApp, or DiffQTF can be non-zero. Used only when WaveDirMod=0]
             0   DiffQTF        - Full difference-frequency 2nd-order forces computed with full QTF          {0: None; [10, 11, or 12]: WAMIT file to use}          [Only one of MnDrift, NewmanApp, or DiffQTF can be non-zero]
             0   SumQTF         - Full summation -frequency 2nd-order forces computed with full QTF          {0: None; [10, 11, or 12]: WAMIT file to use}
---------------------- PLATFORM ADDITIONAL STIFFNESS AND DAMPING  --------------
           0.0   AddF0    - Additional preload (N, N-m) [If NBodyMod=1, one size 6*NBody x 1 vector; if NBodyMod>1, NBody size 6 x 1 vectors]
           0.0   
           0.0   
           0.0   
           0.0   
           0.0  
             0             0             0             0             0             0   AddCLin  - Additional linear stiffness (N/m, N/rad, N-m/m, N-m/rad)
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0   AddBLin  - Additional linear damping(N/(m/s), N/(rad/s), N-m/(m/s), N-m/(rad/s))
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0   AddBQuad - Additional quadratic drag(N/(m/s)^2, N/(rad/s)^2, N-m(m/s)^2, N-m/(rad/s)^2)
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0
             0             0             0             0             0             0
---------------------- AXIAL COEFFICIENTS --------------------------------------
             1   NAxCoef        - Number of axial coefficients (-)
AxCoefID  AxCd     AxCa     AxCp
   (-)    (-)      (-)      (-)
    1     0.00     0.00     1.00
---------------------- MEMBER JOINTS -------------------------------------------
             27   NJoints        - Number of joints (-)   [must be exactly 0 or at least 2]
JointID   Jointxi     Jointyi     Jointzi  JointAxID   JointOvrlp   [JointOvrlp= 0: do nothing at joint, 1: eliminate overlaps by calculating super member]
   (-)     (m)         (m)         (m)        (-)       (switch)
    1   XYZ      1            0
    2   XYZ      1            0
    3   XYZ      1            0
    4   XYZ      1            0
    5   XYZ      1            0
    6   XYZ    1            0
    7   XYZ    1            0
    8   XYZ    1            0
    9   XYZ    1            0
   10   XYZ    1            0
   11   XYZ    1            0
   12   XYZ    1            0
   13   XYZ    1            0
   14	XYZ	   1	        0
   15	XYZ	   1	        0
   16	XYZ	   1	        0
   17	XYZ  1            0
   18	XYZ  1	        0
   19	XYZ  1	        0
   20	XYZ	   1	        0
   21	XYZ	   1	        0
   22	XYZ	   1	        0
   23	XYZ  1	        0
   24	XYZ  1	        0
   25	XYZ  1	        0
   26	XYZ  1	        0
   27	XYZ  1	        0
---------------------- MEMBER CROSS-SECTION PROPERTIES -------------------------
             7   NPropSets      - Number of member property sets (-)
PropSetID    PropD         PropThck
   (-)        (m)            (m)
    1	    D1	    T1         
    2	    D2	    T2         
    3	    D3	    T3         
    4	    D4	    T4         
    5	    D5	    T5         
    6	    D6	    T6             
    7       D7      T7    
---------------------- SIMPLE HYDRODYNAMIC COEFFICIENTS (model 1) --------------
  SimplCd    SimplCdMG    SimplCa    SimplCaMG    SimplCp    SimplCpMG   SimplAxCd  SimplAxCdMG  SimplAxCa  SimplAxCaMG  SimplAxCp  SimplAxCpMG
    (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)    
    1.0         1.0         1.0         1.0         1.0         1.0         0.0         0.0         1.0         1.0         1.0         1.0    
---------------------- DEPTH-BASED HYDRODYNAMIC COEFFICIENTS (model 2) ---------
             0   NCoefDpth       - Number of depth-dependent coefficients (-)
   Dpth       DpthCd     DpthCdMG     DpthCa     DpthCaMG     DpthCp     DpthCpMG    DpthAxCd   DpthAxCdMG   DpthAxCa   DpthAxCaMG   DpthAxCp   DpthAxCpMG 
    (m)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)    
---------------------- MEMBER-BASED HYDRODYNAMIC COEFFICIENTS (model 3) --------
0           NCoefMembers - Number of member-based coefficients (-)
MemberID_HydC  MemberCd1   MemberCd2  MemberCdMG1 MemberCdMG2  MemberCa1   MemberCa2  MemberCaMG1 MemberCaMG2  MemberCp1   MemberCp2  MemberCpMG1 MemberCpMG2 MemberAxCd1 MemberAxCd2 MemberAxCdMG1 MemberAxCdMG2 MemberAxCa1 MemberAxCa2 MemberAxCaMG1 MemberAxCaMG2 MemberAxCp1 MemberAxCp2 MemberAxCpMG1 MemberAxCpMG2
    (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)         (-)    
-------------------- MEMBERS -------------------------------------------------
             44   NMembers       - Number of members (-)
MemberID  MJointID1  MJointID2  MPropSetID1  MPropSetID2  MDivSize   MCoefMod  PropPot   [MCoefMod=1: use simple coeff table, 2: use depth-based coeff table, 3: use member-based coeff table] [ PropPot/=0 if member is modeled with potential-flow theory]
  (-)        (-)        (-)         (-)          (-)        (m)      (switch)   (flag)
     1	    AB	         1	          1         1.0000      1        FALSE
    2	    AB	         1	          1         1.0000      1        FALSE
    3	    AB	         1	          1         1.0000      1        FALSE
    4	    AB	         1	          1         1.0000      1        FALSE
    5	    AB	         2	          2         1.0000      1        FALSE
    6	    AB	         2	          3         1.0000      1        FALSE
    7	    AB	         3	          3         1.0000      1        FALSE
    8	    AB	         3	          3         1.0000      1        FALSE
    9	    AB	         3	          3         1.0000      1        FALSE
   10	    AB	         2	          2         1.0000      1        FALSE
   11	    AB	         2	          3         1.0000      1        FALSE
   12	    AB	         3	          3         1.0000      1        FALSE
   13	    AB	         3	          3         1.0000      1        FALSE
   14	    AB	         3	          3         1.0000      1        FALSE
   15	    AB	         4	          4         1.0000      1        FALSE
   16	    AB	         4	          4         1.0000      1        FALSE
   17	    AB	         4	          4         1.0000      1        FALSE
   18	    AB	         4	          4         1.0000      1        FALSE
   19	    AB	         4	          4         1.0000      1        FALSE
   20	    AB	         5	          5         1.0000      1        FALSE
   21	    AB	         5	          5         1.0000      1        FALSE
   22	    AB	         5	          5         1.0000      1        FALSE
   23	    AB	         5	          5         1.0000      1        FALSE
   24	    AB	         4	          4         1.0000      1        FALSE
   25	    AB	         4	          4         1.0000      1        FALSE
   26	    AB	         4            4         1.0000      1        FALSE
   27	    AB	         4	          4         1.0000      1        FALSE
   28	    AB	         4	          4         1.0000      1        FALSE
   29	    AB	         5	          5         1.0000      1        FALSE
   30	    AB	         5	          5         1.0000      1        FALSE
   31	    AB	         5	          5         1.0000      1        FALSE
   32	    AB	         5	          5         1.0000      1        FALSE
   33	    AB	         4	          4         1.0000      1        FALSE
   34	    AB	         4	          4         1.0000      1        FALSE
   35	    AB	         4	          4         1.0000      1        FALSE
   36	    AB	         4	          4         1.0000      1        FALSE
   37	    AB	         4	          4         1.0000      1        FALSE
   38	    AB	         5	          5         1.0000      1        FALSE
   39	    AB	         5	          5         1.0000      1        FALSE
   40	    AB	         5	          5         1.0000      1        FALSE
   41	    AB	         5	          5         1.0000      1        FALSE
   42	    AB	         6	          6         1.0000      1        FALSE
   43	    AB	         6	          6         1.0000      1        FALSE
   44	    AB	         7	          7         1.0000      1        FALSE
---------------------- FILLED MEMBERS ------------------------------------------
             0   NFillGroups     - Number of filled member groups (-) [If FillDens = DEFAULT, then FillDens = WtrDens; FillFSLoc is related to MSL2SWL]
FillNumM FillMList             FillFSLoc     FillDens
(-)      (-)                   (m)           (kg/m^3)
---------------------- MARINE GROWTH -------------------------------------------
             0   NMGDepths      - Number of marine-growth depths specified (-)
MGDpth     MGThck       MGDens
(m)        (m)         (kg/m^3)
---------------------- MEMBER OUTPUT LIST --------------------------------------
             0   NMOutputs      - Number of member outputs (-) [must be < 10]
MemberID   NOutLoc    NodeLocs [NOutLoc < 10; node locations are normalized distance from the start of the member, and must be >=0 and <= 1] [unused if NMOutputs=0]
  (-)        (-)        (-)
---------------------- JOINT OUTPUT LIST ---------------------------------------
             2   NJOutputs      - Number of joint outputs [Must be < 10]
   1,2           JOutLst        - List of JointIDs which are to be output (-)[unused if NJOutputs=0]
---------------------- OUTPUT --------------------------------------------------
True             HDSum          - Output a summary file [flag]
False            OutAll         - Output all user-specified member and joint loads (only at each member end, not interior locations) [flag]
             2   OutSwtch       - Output requested channels to: [1=Hydrodyn.out, 2=GlueCode.out, 3=both files]
"ES11.4e2"       OutFmt         - Output format for numerical results (quoted string) [not checked for validity!]
"A11"            OutSFmt        - Output format for header strings (quoted string) [not checked for validity!]
---------------------- OUTPUT CHANNELS -----------------------------------------
"Wave1Elev"               - Wave elevation at the WAMIT reference point (0,0)
END of output channels and end of file. (the word "END" must appear in the first 3 columns of this line)

Dear @Pere.Palacin,

Is your model set up following the recommended practice (4.2.8.4. Modeling Considerations — OpenFAST v3.4.1 documentation) such that the system weight balances with the undisplaced buoyancy and vertical pretension of the mooring system?

I also see that you’ve set a pretty strong combination of current profiles; could that be part of the problem?

Best regards,

Dear @Jason.Jonkman ,

Thanks a lot for your reply. I didn’t know about the recommended practices to set up my HydroDyn file. I will review it throughly to try to solve the issue.

I was testing different current speeds as part of my study but I get the same issue with different speeds and the error persisted.

I will try to fix it on my own following the guidelines provided. If I encounter any problem I will ask again.

Thanks a lot,
Best regards.
Pere