diff --git a/model/src/w3profsmd_pdlib.F90 b/model/src/w3profsmd_pdlib.F90
index 6759fb53e..140fdc33b 100644
--- a/model/src/w3profsmd_pdlib.F90
+++ b/model/src/w3profsmd_pdlib.F90
@@ -2854,12 +2854,24 @@ SUBROUTINE PDLIB_W3XYPUG_BLOCK_EXPLICIT(IMOD, FACX, FACY, DTG, VGX, VGY, LCALC)
     !
     USE W3ODATMD, only: IAPROC
     USE W3GDATMD, only: B_JGS_USE_JACOBI
+    USE W3TIMEMD, only: DSEC21
+    USE W3ODATMD, only: TBPI0, TBPIN, FLBPI
+    USE W3WDATMD, only: TIME
 
     LOGICAL, INTENT(IN) :: LCALC
     INTEGER, INTENT(IN) :: IMOD
     REAL, INTENT(IN) :: FACX, FACY, DTG, VGX, VGY
+    REAL             :: RD1, RD2
+
+    IF ( FLBPI ) THEN
+      RD1  = DSEC21 ( TBPI0, TIME )
+      RD2  = DSEC21 ( TBPI0, TBPIN )
+    ELSE
+      RD1=1.
+      RD2=0.
+    END IF
 
-    CALL PDLIB_EXPLICIT_BLOCK(IMOD, FACX, FACY, DTG, VGX, VGY, LCALC)
+    CALL PDLIB_EXPLICIT_BLOCK(IMOD, FACX, FACY, RD1, RD2, DTG, VGX, VGY, LCALC)
     !/
     !/ End of W3XYPFSN ----------------------------------------------------- /
     !/
@@ -6328,7 +6340,7 @@ SUBROUTINE PDLIB_JACOBI_GAUSS_SEIDEL_BLOCK(IMOD, FACX, FACY, DTG, VGX, VGY, LCAL
 #endif
   END SUBROUTINE PDLIB_JACOBI_GAUSS_SEIDEL_BLOCK
   !/ ------------------------------------------------------------------- /
-  SUBROUTINE PDLIB_EXPLICIT_BLOCK(IMOD, FACX, FACY, DTG, VGX, VGY, LCALC)
+  SUBROUTINE PDLIB_EXPLICIT_BLOCK(IMOD, FACX, FACY, RD10, RD20, DTG, VGX, VGY, LCALC)
     !/
     !/                  +-----------------------------------+
     !/                  | WAVEWATCH III           NOAA/NCEP |
@@ -6402,7 +6414,7 @@ SUBROUTINE PDLIB_EXPLICIT_BLOCK(IMOD, FACX, FACY, DTG, VGX, VGY, LCALC)
 
     INTEGER, INTENT(IN) :: IMOD
 
-    REAL, INTENT(IN)    :: FACX, FACY, DTG, VGX, VGY
+    REAL, INTENT(IN)    :: FACX, FACY, DTG, VGX, VGY, RD10, RD20
 
     REAL              :: KTMP(3), UTILDE(NTH), ST(NTH,NPA)
     REAL              :: FL11(NTH), FL12(NTH), FL21(NTH), FL22(NTH), FL31(NTH), FL32(NTH), KKSUM(NTH,NPA)
@@ -6411,7 +6423,7 @@ SUBROUTINE PDLIB_EXPLICIT_BLOCK(IMOD, FACX, FACY, DTG, VGX, VGY, LCALC)
     REAL              :: KSIG(NPA), CGSIG(NPA), CXX(NTH,NPA), CYY(NTH,NPA)
     REAL              :: LAMBDAX(NTH), LAMBDAY(NTH)
     REAL              :: DTMAX(NTH), DTMAXEXP(NTH), DTMAXOUT, DTMAXGL
-    REAL              :: FIN(1), FOUT(1), REST, CFLXY, RD1, RD2, RD10, RD20
+    REAL              :: FIN(1), FOUT(1), REST, CFLXY, RD1, RD2
     REAL              :: UOLD(NTH,NPA), U(NTH,NPA)
 
     REAL, PARAMETER   :: ONESIXTH = 1.0/6.0
@@ -6570,8 +6582,8 @@ SUBROUTINE PDLIB_EXPLICIT_BLOCK(IMOD, FACX, FACY, DTG, VGX, VGY, LCALC)
         IF ( FLBPI ) THEN
           DO ITH = 1, NTH
             ISP = ITH + (IK-1) * NTH
-            RD1 = RD10 - DTG * REAL(ITER(IK)-IT)/REAL(ITER(IK))
-            RD2 = RD20
+            RD1=RD10 - DTMAXGL * REAL(ITER(IK)-IT)/REAL(ITER(IK))
+            RD2=RD20
             IF ( RD2 .GT. 0.001 ) THEN
               RD2    = MIN(1.,MAX(0.,RD1/RD2))
               RD1    = 1. - RD2
diff --git a/model/src/w3sdb1md.F90 b/model/src/w3sdb1md.F90
index 34c7ec3bf..7b4c0ce02 100644
--- a/model/src/w3sdb1md.F90
+++ b/model/src/w3sdb1md.F90
@@ -187,6 +187,7 @@ SUBROUTINE W3SDB1 (IX, A, DEPTH, EMEAN, FMEAN, WNMEAN, CG, LBREAK, S, D )
     USE W3ODATMD, ONLY: NDST
     USE W3GDATMD, ONLY: SIG
     USE W3ODATMD, only : IAPROC
+    USE W3PARALL, only : THR 
 #ifdef W3_S
     USE W3SERVMD, ONLY: STRACE
 #endif
@@ -218,7 +219,7 @@ SUBROUTINE W3SDB1 (IX, A, DEPTH, EMEAN, FMEAN, WNMEAN, CG, LBREAK, S, D )
     INTEGER, SAVE           :: IENT = 0
 #endif
     REAL*8                    :: HM, BB, ARG, Q0, QB, B, CBJ, HRMS, EB(NK)
-    REAL*8                    :: AUX, CBJ2, RATIO, S0, S1, THR, BR1, BR2, FAK
+    REAL*8                    :: AUX, CBJ2, RATIO, S0, S1, BR1, BR2, FAK
     REAL                      :: ETOT, FMEAN2
 #ifdef W3_T0
     REAL                    :: DOUT(NK,NTH)
@@ -231,12 +232,9 @@ SUBROUTINE W3SDB1 (IX, A, DEPTH, EMEAN, FMEAN, WNMEAN, CG, LBREAK, S, D )
 #endif
     !
     ! 0.  Initialzations ------------------------------------------------- /
-    !     Never touch this 4 lines below ... otherwise my exceptionhandling will not work.
-    S = 0.
-    D = 0.
-
-    THR = DBLE(1.E-15)
-    IF (SUM(A) .LT. THR) RETURN
+    IF (EMEAN .LT. TINY(1.d0)) THEN
+      RETURN
+    ENDIF
 
     IWB = 1
     !
diff --git a/model/src/w3srcemd.F90 b/model/src/w3srcemd.F90
index e90ba88eb..eeb2a95a1 100644
--- a/model/src/w3srcemd.F90
+++ b/model/src/w3srcemd.F90
@@ -1,4 +1,4 @@
-!> @file
+
 !> @brief Source term integration routine.
 !>
 !> @author H. L. Tolman
@@ -1244,7 +1244,7 @@ SUBROUTINE W3SRCE ( srce_call, IT, ISEA, JSEA, IX, IY, IMOD,          &
       IF (.NOT. FSSOURCE .or. LSLOC) THEN
 #endif
 #ifdef W3_TR1
-        CALL W3STR1 ( SPEC, SPECOLD, CG1, WN1, DEPTH, IX,        VSTR, VDTR )
+        CALL W3STR1 ( SPEC, CG1, WN1, DEPTH, IX, VSTR, VDTR )
 #endif
 #ifdef W3_PDLIB
       ENDIF
@@ -1534,8 +1534,13 @@ SUBROUTINE W3SRCE ( srce_call, IT, ISEA, JSEA, IX, IY, IMOD,          &
                   DVS  = SIGN(MIN(MAXDAC,ABS(DVS)),DVS)
                 ENDIF
                 PreVS  = DVS / FAKS
-                eVS    = PreVS / CG1(IK) * CLATSL
-                eVD    = MIN(0.,VD(ISP))
+                IF (IOBP_LOC(JSEA) .EQ. 3) THEN
+                  eVS = 0
+                  eVD = 0
+                ELSE
+                  eVS    = PreVS / CG1(IK) * CLATSL
+                  eVD    = MIN(0.,VD(ISP))
+                ENDIF
                 B_JAC(ISP,JSEA)                   = B_JAC(ISP,JSEA) + SIDT * (eVS - eVD*SPEC(ISP)*JAC)
                 ASPAR_JAC(ISP,PDLIB_I_DIAG(JSEA)) = ASPAR_JAC(ISP,PDLIB_I_DIAG(JSEA)) - SIDT * eVD
 #ifdef W3_DB1
@@ -1548,9 +1553,9 @@ SUBROUTINE W3SRCE ( srce_call, IT, ISEA, JSEA, IX, IY, IMOD,          &
                   evS = -evS
                   evD = 2*evD
                 ENDIF
-#endif
                 B_JAC(ISP,JSEA)                   = B_JAC(ISP,JSEA) + SIDT * eVS
                 ASPAR_JAC(ISP,PDLIB_I_DIAG(JSEA)) = ASPAR_JAC(ISP,PDLIB_I_DIAG(JSEA)) - SIDT * eVD
+#endif
 
 #ifdef W3_TR1
                 eVS = VSTR(ISP) * JAC
@@ -1562,9 +1567,9 @@ SUBROUTINE W3SRCE ( srce_call, IT, ISEA, JSEA, IX, IY, IMOD,          &
                   evS = -evS
                   evD = 2*evD
                 ENDIF
-#endif
                 B_JAC(ISP,JSEA)                   = B_JAC(ISP,JSEA) + SIDT * eVS
                 ASPAR_JAC(ISP,PDLIB_I_DIAG(JSEA)) = ASPAR_JAC(ISP,PDLIB_I_DIAG(JSEA)) - SIDT * eVD
+#endif
               END DO
             END DO
 
diff --git a/model/src/w3str1md.F90 b/model/src/w3str1md.F90
index d8067abd7..ce14b6b36 100644
--- a/model/src/w3str1md.F90
+++ b/model/src/w3str1md.F90
@@ -180,7 +180,7 @@ MODULE W3STR1MD
   !>
   !> @author A. J. van der Westhuysen  @date 13-Jan-2013
   !>
-  SUBROUTINE W3STR1 (A, AOLD, CG, WN, DEPTH, IX, S, D)
+  SUBROUTINE W3STR1 (A, CG, WN, DEPTH, IX, S, D)
     !/
     !/                  +-----------------------------------+
     !/                  | WAVEWATCH III           NOAA/NCEP |
@@ -259,7 +259,6 @@ SUBROUTINE W3STR1 (A, AOLD, CG, WN, DEPTH, IX, S, D)
     !       CG      R.A.  I   Group velocities.
     !       WN      R.A.  I   Wavenumbers.
     !       DEPTH   Real  I   Mean water depth.
-    !       EMEAN   Real  I   Mean wave energy.
     !       FMEAN   Real  I   Mean wave frequency.
     !       S       R.A.  O   Source term (1-D version).
     !       D       R.A.  O   Diagonal term of derivative (1-D version).
@@ -320,7 +319,7 @@ SUBROUTINE W3STR1 (A, AOLD, CG, WN, DEPTH, IX, S, D)
     !/ ------------------------------------------------------------------- /
     !/ Parameter list
     !/
-    REAL, INTENT(IN)        :: CG(NK), WN(NK), DEPTH, A(NSPEC), AOLD(NSPEC) 
+    REAL, INTENT(IN)        :: CG(NK), WN(NK), DEPTH, A(NSPEC)
     INTEGER, INTENT(IN)     :: IX
     REAL, INTENT(OUT)       :: S(NSPEC), D(NSPEC)
     !/
@@ -391,11 +390,13 @@ SUBROUTINE W3STR1 (A, AOLD, CG, WN, DEPTH, IX, S, D)
 #ifdef W3_S
     CALL STRACE (IENT, 'W3STR1')
 #endif
-
-!AR: todo: check all PRX routines for differences, check original thesis of elderberky. 
 !
 ! 1.  Integral over directions
 !
+    IF (MAXVAL(A) .LT. TINY(1.)) THEN
+      RETURN 
+    ENDIF 
+
     SIGM01 = 0.
     EMEAN  = 0.
     JACEPS = 1E-12
diff --git a/model/src/w3wavemd.F90 b/model/src/w3wavemd.F90
index 6db2f03af..83d3be9e5 100644
--- a/model/src/w3wavemd.F90
+++ b/model/src/w3wavemd.F90
@@ -1453,6 +1453,12 @@ SUBROUTINE W3WAVE ( IMOD, ODAT, TEND, STAMP, NO_OUT &
         call print_memcheck(memunit, 'memcheck_____:'//' WW3_WAVE TIME LOOP 13')
         !
 #ifdef W3_PDLIB
+
+        IF (LPDLIB .and. .not. FLSOU .and. .not. FSSOURCE) THEN
+          B_JAC     = 0.
+          ASPAR_JAC = 0.
+        ENDIF
+
         IF (LPDLIB .and. FLSOU .and. FSSOURCE) THEN
 #endif
 
@@ -1484,6 +1490,8 @@ SUBROUTINE W3WAVE ( IMOD, ODAT, TEND, STAMP, NO_OUT &
 
             CALL INIT_GET_ISEA(ISEA, JSEA)
 
+            IF ((IOBP_LOC(JSEA).eq.1..or.IOBP_LOC(JSEA).eq. 3).and.IOBDP_LOC(JSEA).eq.1.and.IOBPA_LOC(JSEA).eq.0) THEN
+
             IX     = MAPSF(ISEA,1)
             IY     = MAPSF(ISEA,2)
             DELA=1.
@@ -1556,6 +1564,7 @@ SUBROUTINE W3WAVE ( IMOD, ODAT, TEND, STAMP, NO_OUT &
             WRITE(740+IAPROC,*) '     SHAVETOT=', SHAVETOT(JSEA)
             FLUSH(740+IAPROC)
 #endif
+          ENDIF 
           END DO ! JSEA
         END IF ! PDLIB
 #endif
@@ -2158,6 +2167,7 @@ SUBROUTINE W3WAVE ( IMOD, ODAT, TEND, STAMP, NO_OUT &
             !
             DO JSEA=1, NSEAL
               CALL INIT_GET_ISEA(ISEA, JSEA)
+
               IX     = MAPSF(ISEA,1)
               IY     = MAPSF(ISEA,2)
               DELA=1.