diff --git a/CMakeLists_files.cmake b/CMakeLists_files.cmake
index 90343d178..d83d65a06 100644
--- a/CMakeLists_files.cmake
+++ b/CMakeLists_files.cmake
@@ -109,6 +109,7 @@ list (APPEND MAIN_SOURCE_FILES
   opm/simulators/flow/partitionCells.cpp
   opm/simulators/flow/RSTConv.cpp
   opm/simulators/flow/RegionPhasePVAverage.cpp
+  opm/simulators/flow/SimulatorConvergenceOutput.cpp
   opm/simulators/flow/SimulatorReportBanners.cpp
   opm/simulators/flow/SimulatorSerializer.cpp
   opm/simulators/flow/SolutionContainers.cpp
@@ -843,6 +844,7 @@ list (APPEND PUBLIC_HEADER_FILES
   opm/simulators/flow/priVarsPacking.hpp
   opm/simulators/flow/RSTConv.hpp
   opm/simulators/flow/RegionPhasePVAverage.hpp
+  opm/simulators/flow/SimulatorConvergenceOutput.hpp
   opm/simulators/flow/SimulatorFullyImplicitBlackoil.hpp
   opm/simulators/flow/SimulatorReportBanners.hpp
   opm/simulators/flow/SimulatorSerializer.hpp
diff --git a/opm/simulators/flow/SimulatorConvergenceOutput.cpp b/opm/simulators/flow/SimulatorConvergenceOutput.cpp
new file mode 100644
index 000000000..a96028705
--- /dev/null
+++ b/opm/simulators/flow/SimulatorConvergenceOutput.cpp
@@ -0,0 +1,94 @@
+/*
+  Copyright 2013, 2015, 2020 SINTEF Digital, Mathematics and Cybernetics.
+  Copyright 2015 Andreas Lauser
+  Copyright 2017 IRIS
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include <config.h>
+#include <opm/simulators/flow/SimulatorConvergenceOutput.hpp>
+
+#include <opm/input/eclipse/EclipseState/EclipseState.hpp>
+#include <opm/input/eclipse/EclipseState/IOConfig/IOConfig.hpp>
+
+#include <opm/simulators/flow/ConvergenceOutputConfiguration.hpp>
+
+namespace Opm {
+
+void SimulatorConvergenceOutput::
+startThread(std::string_view convOutputOptions,
+            std::string_view optionName,
+            ConvergenceOutputThread::ComponentToPhaseName getPhaseName)
+{
+    const auto config = ConvergenceOutputConfiguration {
+        convOutputOptions, optionName
+    };
+
+    if (! config.want(ConvergenceOutputConfiguration::Option::Iterations)) {
+        return;
+    }
+
+    auto convertTime = ConvergenceOutputThread::ConvertToTimeUnits {
+        [usys = eclState_.getUnits()](const double time)
+        { return usys.from_si(UnitSystem::measure::time, time); }
+    };
+
+    this->convergenceOutputQueue_.emplace();
+    this->convergenceOutputObject_.emplace
+        (eclState_.getIOConfig().getOutputDir(),
+         eclState_.getIOConfig().getBaseName(),
+         std::move(getPhaseName),
+         std::move(convertTime),
+         config, *this->convergenceOutputQueue_);
+
+    this->convergenceOutputThread_
+        .emplace(&ConvergenceOutputThread::writeASynchronous,
+                 &this->convergenceOutputObject_.value());
+}
+
+void SimulatorConvergenceOutput::
+write(const std::vector<StepReport>& reports)
+{
+    if (! this->convergenceOutputThread_.has_value()) {
+        return;
+    }
+
+    auto new_reports = std::vector<StepReport> {
+        reports.begin() + this->already_reported_steps_, reports.end()
+    };
+
+    auto requests = std::vector<ConvergenceReportQueue::OutputRequest>{};
+    requests.reserve(new_reports.size());
+
+    for (auto&& report : new_reports) {
+        requests.push_back({ report.report_step, report.current_step, std::move(report.report) });
+    }
+    this->already_reported_steps_ = reports.size();
+
+    this->convergenceOutputQueue_->enqueue(std::move(requests));
+}
+
+void SimulatorConvergenceOutput::endThread()
+{
+    if (! this->convergenceOutputThread_.has_value()) {
+        return;
+    }
+
+    this->convergenceOutputQueue_->signalLastOutputRequest();
+    this->convergenceOutputThread_->join();
+}
+
+} // namespace Opm
diff --git a/opm/simulators/flow/SimulatorConvergenceOutput.hpp b/opm/simulators/flow/SimulatorConvergenceOutput.hpp
new file mode 100644
index 000000000..37aebe86c
--- /dev/null
+++ b/opm/simulators/flow/SimulatorConvergenceOutput.hpp
@@ -0,0 +1,66 @@
+/*
+  Copyright 2013, 2015, 2020 SINTEF Digital, Mathematics and Cybernetics.
+  Copyright 2015 Andreas Lauser
+  Copyright 2017 IRIS
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef OPM_SIMULATOR_CONVERGENCE_OUTPUT_HEADER_INCLUDED
+#define OPM_SIMULATOR_CONVERGENCE_OUTPUT_HEADER_INCLUDED
+
+#include <opm/simulators/flow/ExtraConvergenceOutputThread.hpp>
+
+#include <cstddef>
+#include <optional>
+#include <string_view>
+#include <thread>
+#include <vector>
+
+namespace Opm {
+
+class EclipseState;
+struct StepReport;
+
+/// Class handling convergence history output for a simulator.
+class SimulatorConvergenceOutput
+{
+public:
+    explicit SimulatorConvergenceOutput(const EclipseState& eclState)
+        : eclState_(eclState)
+    {}
+
+    void startThread(std::string_view convOutputOptions,
+                     std::string_view optionName,
+                     ConvergenceOutputThread::ComponentToPhaseName getPhaseName);
+
+    void write(const std::vector<StepReport>& reports);
+
+    void endThread();
+
+private:
+    const EclipseState& eclState_;
+
+    std::size_t already_reported_steps_ = 0;
+
+    std::optional<ConvergenceReportQueue> convergenceOutputQueue_{};
+    std::optional<ConvergenceOutputThread> convergenceOutputObject_{};
+    std::optional<std::thread> convergenceOutputThread_{};
+};
+
+} // namespace Opm
+
+#endif // OPM_SIMULATOR_CONVERGENCE_OUTPUT_HEADER_INCLUDED
diff --git a/opm/simulators/flow/SimulatorFullyImplicitBlackoil.hpp b/opm/simulators/flow/SimulatorFullyImplicitBlackoil.hpp
index 14b663dc2..01ee43d34 100644
--- a/opm/simulators/flow/SimulatorFullyImplicitBlackoil.hpp
+++ b/opm/simulators/flow/SimulatorFullyImplicitBlackoil.hpp
@@ -34,6 +34,7 @@
 #include <opm/simulators/flow/ConvergenceOutputConfiguration.hpp>
 #include <opm/simulators/flow/ExtraConvergenceOutputThread.hpp>
 #include <opm/simulators/flow/NonlinearSolver.hpp>
+#include <opm/simulators/flow/SimulatorConvergenceOutput.hpp>
 #include <opm/simulators/flow/SimulatorReportBanners.hpp>
 #include <opm/simulators/flow/SimulatorSerializer.hpp>
 #include <opm/simulators/timestepping/AdaptiveTimeStepping.hpp>
@@ -45,18 +46,15 @@
 #include <opm/simulators/utils/HDF5Serializer.hpp>
 #endif
 
-#include <fmt/format.h>
-
-#include <cstddef>
 #include <filesystem>
 #include <memory>
-#include <optional>
 #include <string>
 #include <string_view>
-#include <thread>
 #include <utility>
 #include <vector>
 
+#include <fmt/format.h>
+
 namespace Opm::Parameters {
 
 struct EnableAdaptiveTimeStepping { static constexpr bool value = true; };
@@ -117,8 +115,9 @@ public:
     /// \param[in] eclipse_state the object which represents an internalized ECL deck
     /// \param[in] output_writer
     /// \param[in] threshold_pressures_by_face   if nonempty, threshold pressures that inhibit flow
-    SimulatorFullyImplicitBlackoil(Simulator& simulator)
+    explicit SimulatorFullyImplicitBlackoil(Simulator& simulator)
         : simulator_(simulator)
+        , convergence_output_(simulator_.vanguard().eclState())
         , serializer_(*this,
                       FlowGenericVanguard::comm(),
                       simulator_.vanguard().eclState().getIOConfig(),
@@ -134,15 +133,22 @@ public:
         if (this->grid().comm().rank() == 0) {
             this->terminalOutput_ = Parameters::Get<Parameters::EnableTerminalOutput>();
 
-            this->startConvergenceOutputThread(Parameters::Get<Parameters::OutputExtraConvergenceInfo>(),
-                                               R"(OutputExtraConvergenceInfo (--output-extra-convergence-info))");
+            auto getPhaseName = ConvergenceOutputThread::ComponentToPhaseName {
+                [compNames = typename Model::ComponentName{}](const int compIdx)
+                { return std::string_view { compNames.name(compIdx) }; }
+            };
+
+            convergence_output_.
+                startThread(Parameters::Get<Parameters::OutputExtraConvergenceInfo>(),
+                            R"(OutputExtraConvergenceInfo (--output-extra-convergence-info))",
+                            getPhaseName);
         }
     }
 
     ~SimulatorFullyImplicitBlackoil()
     {
         // Safe to call on all ranks, not just the I/O rank.
-        this->endConvergenceOutputThread();
+        convergence_output_.endThread();
     }
 
     static void registerParameters()
@@ -420,14 +426,7 @@ public:
             // Grab the step convergence reports that are new since last we
             // were here.
             const auto& reps = this->solver_->model().stepReports();
-
-            auto reports = std::vector<StepReport> {
-                reps.begin() + this->already_reported_steps_, reps.end()
-            };
-
-            this->writeConvergenceOutput(std::move(reports));
-
-            this->already_reported_steps_ = reps.size();
+            convergence_output_.write(reps);
         }
 
         // Increment timer, remember well state.
@@ -563,65 +562,6 @@ protected:
     const WellModel& wellModel_() const
     { return simulator_.problem().wellModel(); }
 
-    void startConvergenceOutputThread(std::string_view convOutputOptions,
-                                      std::string_view optionName)
-    {
-        const auto config = ConvergenceOutputConfiguration {
-            convOutputOptions, optionName
-        };
-        if (! config.want(ConvergenceOutputConfiguration::Option::Iterations)) {
-            return;
-        }
-
-        auto getPhaseName = ConvergenceOutputThread::ComponentToPhaseName {
-            [compNames = typename Model::ComponentName{}](const int compIdx)
-            { return std::string_view { compNames.name(compIdx) }; }
-        };
-
-        auto convertTime = ConvergenceOutputThread::ConvertToTimeUnits {
-            [usys = this->eclState().getUnits()](const double time)
-            { return usys.from_si(UnitSystem::measure::time, time); }
-        };
-
-        this->convergenceOutputQueue_.emplace();
-        this->convergenceOutputObject_.emplace
-            (this->eclState().getIOConfig().getOutputDir(),
-             this->eclState().getIOConfig().getBaseName(),
-             std::move(getPhaseName),
-             std::move(convertTime),
-             config, *this->convergenceOutputQueue_);
-
-        this->convergenceOutputThread_
-            .emplace(&ConvergenceOutputThread::writeASynchronous,
-                     &this->convergenceOutputObject_.value());
-    }
-
-    void writeConvergenceOutput(std::vector<StepReport>&& reports)
-    {
-        if (! this->convergenceOutputThread_.has_value()) {
-            return;
-        }
-
-        auto requests = std::vector<ConvergenceReportQueue::OutputRequest>{};
-        requests.reserve(reports.size());
-
-        for (auto&& report : reports) {
-            requests.push_back({ report.report_step, report.current_step, std::move(report.report) });
-        }
-
-        this->convergenceOutputQueue_->enqueue(std::move(requests));
-    }
-
-    void endConvergenceOutputThread()
-    {
-        if (! this->convergenceOutputThread_.has_value()) {
-            return;
-        }
-
-        this->convergenceOutputQueue_->signalLastOutputRequest();
-        this->convergenceOutputThread_->join();
-    }
-
     // Data.
     Simulator& simulator_;
 
@@ -636,14 +576,11 @@ protected:
     bool terminalOutput_;
 
     SimulatorReport report_;
-    std::size_t already_reported_steps_ = 0;
     std::unique_ptr<time::StopWatch> solverTimer_;
     std::unique_ptr<time::StopWatch> totalTimer_;
     std::unique_ptr<TimeStepper> adaptiveTimeStepping_;
 
-    std::optional<ConvergenceReportQueue> convergenceOutputQueue_{};
-    std::optional<ConvergenceOutputThread> convergenceOutputObject_{};
-    std::optional<std::thread> convergenceOutputThread_{};
+    SimulatorConvergenceOutput convergence_output_;
 
     SimulatorSerializer serializer_;
 };