diff --git a/opm/parser/eclipse/EclipseState/EclipseState.hpp b/opm/parser/eclipse/EclipseState/EclipseState.hpp
index fa672507e..2a74c182c 100644
--- a/opm/parser/eclipse/EclipseState/EclipseState.hpp
+++ b/opm/parser/eclipse/EclipseState/EclipseState.hpp
@@ -122,10 +122,10 @@ namespace Opm {
             serializer(m_runspec);
             serializer(m_eclipseConfig);
             serializer(m_deckUnitSystem);
-            serializer(m_inputNnc);
-            serializer(m_inputEditNnc);
-            serializer(m_gridDims);
-            serializer(m_simulationConfig);
+            m_inputNnc.serializeOp(serializer);
+            m_inputEditNnc.serializeOp(serializer);
+            m_gridDims.serializeOp(serializer);
+            m_simulationConfig.serializeOp(serializer);
             serializer(m_transMult);
             serializer(m_faults);
             serializer(m_title);
diff --git a/opm/parser/eclipse/EclipseState/Edit/EDITNNC.hpp b/opm/parser/eclipse/EclipseState/Edit/EDITNNC.hpp
index c85027555..105bb221e 100644
--- a/opm/parser/eclipse/EclipseState/Edit/EDITNNC.hpp
+++ b/opm/parser/eclipse/EclipseState/Edit/EDITNNC.hpp
@@ -46,6 +46,12 @@ public:
 
     bool operator==(const EDITNNC& data) const;
 
+    template<class Serializer>
+    void serializeOp(Serializer& serializer)
+    {
+        serializer.vector(m_editnnc);
+    }
+
 private:
     std::vector<NNCdata> m_editnnc;
 };
diff --git a/opm/parser/eclipse/EclipseState/Grid/GridDims.hpp b/opm/parser/eclipse/EclipseState/Grid/GridDims.hpp
index 3f72d13dc..caab756cd 100644
--- a/opm/parser/eclipse/EclipseState/Grid/GridDims.hpp
+++ b/opm/parser/eclipse/EclipseState/Grid/GridDims.hpp
@@ -59,6 +59,14 @@ namespace Opm {
 
         bool operator==(const GridDims& data) const;
 
+        template<class Serializer>
+        void serializeOp(Serializer& serializer)
+        {
+            serializer(m_nx);
+            serializer(m_ny);
+            serializer(m_nz);
+        }
+
     protected:
         size_t m_nx;
         size_t m_ny;
diff --git a/opm/parser/eclipse/EclipseState/Grid/NNC.hpp b/opm/parser/eclipse/EclipseState/Grid/NNC.hpp
index c08d53e28..1c5099dfb 100644
--- a/opm/parser/eclipse/EclipseState/Grid/NNC.hpp
+++ b/opm/parser/eclipse/EclipseState/Grid/NNC.hpp
@@ -40,6 +40,14 @@ struct NNCdata {
                trans == data.trans;
     }
 
+    template<class Serializer>
+    void serializeOp(Serializer& serializer)
+    {
+        serializer(cell1);
+        serializer(cell2);
+        serializer(trans);
+    }
+
     size_t cell1;
     size_t cell2;
     double trans;
@@ -64,6 +72,12 @@ public:
 
     bool operator==(const NNC& data) const;
 
+    template<class Serializer>
+    void serializeOp(Serializer& serializer)
+    {
+        serializer.vector(m_nnc);
+    }
+
 private:
 
     std::vector<NNCdata> m_nnc;
diff --git a/opm/parser/eclipse/EclipseState/SimulationConfig/BCConfig.hpp b/opm/parser/eclipse/EclipseState/SimulationConfig/BCConfig.hpp
index c25d43fc6..c50859a24 100644
--- a/opm/parser/eclipse/EclipseState/SimulationConfig/BCConfig.hpp
+++ b/opm/parser/eclipse/EclipseState/SimulationConfig/BCConfig.hpp
@@ -69,6 +69,21 @@ public:
                BCComponent comp_arg,
                double rate_arg);
         bool operator==(const BCFace& other) const;
+
+        template<class Serializer>
+        void serializeOp(Serializer& serializer)
+        {
+            serializer(i1);
+            serializer(i2);
+            serializer(j1);
+            serializer(j2);
+            serializer(k1);
+            serializer(k2);
+            serializer(bctype);
+            serializer(dir);
+            serializer(component);
+            serializer(rate);
+        }
     };
 
 
@@ -80,6 +95,13 @@ public:
     std::vector<BCFace>::const_iterator begin() const;
     std::vector<BCFace>::const_iterator end() const;
     bool operator==(const BCConfig& other) const;
+
+    template<class Serializer>
+    void serializeOp(Serializer& serializer)
+    {
+        serializer.vector(m_faces);
+    }
+
 private:
     std::vector<BCFace> m_faces;
 };
diff --git a/opm/parser/eclipse/EclipseState/SimulationConfig/RockConfig.hpp b/opm/parser/eclipse/EclipseState/SimulationConfig/RockConfig.hpp
index 5a163cfaa..67192ec44 100644
--- a/opm/parser/eclipse/EclipseState/SimulationConfig/RockConfig.hpp
+++ b/opm/parser/eclipse/EclipseState/SimulationConfig/RockConfig.hpp
@@ -49,6 +49,13 @@ struct RockComp {
     RockComp() = default;
     RockComp(double pref_arg, double comp_arg);
     bool operator==(const RockComp& other) const;
+
+    template<class Serializer>
+    void serializeOp(Serializer& serializer)
+    {
+        serializer(pref);
+        serializer(compressibility);
+    }
 };
 
 
@@ -64,6 +71,18 @@ struct RockComp {
     bool water_compaction() const;
 
     bool operator==(const RockConfig& other) const;
+
+    template<class Serializer>
+    void serializeOp(Serializer& serializer)
+    {
+        serializer(m_active);
+        serializer.vector(m_comp);
+        serializer(num_property);
+        serializer(num_tables);
+        serializer(m_water_compaction);
+        serializer(hyst_mode);
+    }
+
 private:
     bool m_active = false;
     std::vector<RockComp> m_comp;
diff --git a/opm/parser/eclipse/EclipseState/SimulationConfig/SimulationConfig.hpp b/opm/parser/eclipse/EclipseState/SimulationConfig/SimulationConfig.hpp
index a2553c17c..0104a1fed 100644
--- a/opm/parser/eclipse/EclipseState/SimulationConfig/SimulationConfig.hpp
+++ b/opm/parser/eclipse/EclipseState/SimulationConfig/SimulationConfig.hpp
@@ -53,6 +53,18 @@ namespace Opm {
 
         bool operator==(const SimulationConfig& data) const;
 
+        template<class Serializer>
+        void serializeOp(Serializer& serializer)
+        {
+            m_ThresholdPressure.serializeOp(serializer);
+            m_bcconfig.serializeOp(serializer);
+            m_rock_config.serializeOp(serializer);
+            serializer(m_useCPR);
+            serializer(m_DISGAS);
+            serializer(m_VAPOIL);
+            serializer(m_isThermal);
+        }
+
     private:
         ThresholdPressure m_ThresholdPressure;
         BCConfig m_bcconfig;
diff --git a/opm/parser/eclipse/EclipseState/SimulationConfig/ThresholdPressure.hpp b/opm/parser/eclipse/EclipseState/SimulationConfig/ThresholdPressure.hpp
index 77706dc85..24d993cdd 100644
--- a/opm/parser/eclipse/EclipseState/SimulationConfig/ThresholdPressure.hpp
+++ b/opm/parser/eclipse/EclipseState/SimulationConfig/ThresholdPressure.hpp
@@ -74,13 +74,17 @@ namespace Opm {
         bool active() const;
         bool restart() const;
 
-        const ThresholdPressureTable& thresholdPressureTable() const
-        { return m_thresholdPressureTable; }
-
-        const PressureTable& pressureTable() const
-        { return m_pressureTable; }
-
         bool operator==(const ThresholdPressure& data) const;
+
+        template<class Serializer>
+        void serializeOp(Serializer& serializer)
+        {
+            serializer(m_active);
+            serializer(m_restart);
+            serializer(m_thresholdPressureTable);
+            serializer(m_pressureTable);
+        }
+
     private:
         bool m_active;
         bool m_restart;
diff --git a/src/opm/parser/eclipse/EclipseState/SimulationConfig/ThresholdPressure.cpp b/src/opm/parser/eclipse/EclipseState/SimulationConfig/ThresholdPressure.cpp
index 4ded494d5..0238ef77b 100644
--- a/src/opm/parser/eclipse/EclipseState/SimulationConfig/ThresholdPressure.cpp
+++ b/src/opm/parser/eclipse/EclipseState/SimulationConfig/ThresholdPressure.cpp
@@ -218,8 +218,8 @@ namespace Opm {
     bool ThresholdPressure::operator==(const ThresholdPressure& data) const {
         return this->active() == data.active() &&
                this->restart() == data.restart() &&
-               this->thresholdPressureTable() == data.thresholdPressureTable() &&
-               this->pressureTable() == data.pressureTable();
+               this->m_thresholdPressureTable == data.m_thresholdPressureTable &&
+               this->m_pressureTable == data.m_pressureTable;
     }