diff --git a/examples/worlds/buoyancy_engine.sdf b/examples/worlds/buoyancy_engine.sdf
new file mode 100644
index 0000000000..145e955cab
--- /dev/null
+++ b/examples/worlds/buoyancy_engine.sdf
@@ -0,0 +1,142 @@
+<?xml version="1.0" ?>
+<!--
+This example shows you how to use the BuoyancyEngine system to
+control the buoyancy of an underwater glider. It uses Archimedes'
+principle to apply an upward force based on the volume of the bladder. It
+listens to the topic `buoyancy_engine` or
+/model/{namespace}/buoyancy_engine` topic for the volume of the bladder in
+*cubicmeters*.
+## Parameters
+<link_name> - The link which the plugin is attached to [required, string]
+<namespace> - The namespace for the topic. If empty the plugin will listen
+  on `buoyancy_engine` otherwise it listens on
+  `/model/{namespace}/buoyancy_engine` [optional, string]
+<min_volume> - Minimum volume of the engine [optional, float,
+  default=0.00003m^3]
+<neutral_volume> - At this volume the engine has neutral buoyancy. Used to
+  estimate the weight of the engine [optional, float, default=0.0003m^3]
+<default_volume> - The volume which the engine starts at [optional, float,
+  default=0.0003m^3]
+<max_volume> - Maximum volume of the engine [optional, float,
+  default=0.00099m^3]
+<max_inflation_rate> - Maximum inflation rate for bladder [optional,
+  float, default=0.000003m^3/s]
+<fluid_density> - The fluid density of the liquid its suspended in kgm^-3.
+  [optional, float, default=1000kgm^-3]
+## Topics
+* Subscribes to a ignition::msgs::Double on `buoyancy_engine` or
+ `/model/{namespace}/buoyancy_engine`. This is the set point for the
+ engine.
+* Publishes a ignition::msgs::Double on `buoyancy_engine` or
+ `/model/{namespace}/buoyancy_engine/current_volume` on the current volume
+## Examples
+To get started run:
+```
+ign gazebo buoyancy_engine.sdf
+```
+Enter the following in a separate terminal:
+```
+ign topic -t  /model/buoyant_box/buoyancy_engine/ -m ignition.msgs.Double
+   -p "data: 0.003"
+```
+To see the box float up.
+```
+ign topic -t  /model/buoyant_box/buoyancy_engine/ -m ignition.msgs.Double
+   -p "data: 0.001"
+```
+To see the box go down.
+To see the current volume enter:
+```
+ign topic -t  /model/buoyant_box/buoyancy_engine/current_volume -e
+```
+-->
+<sdf version="1.6">
+  <world name="buoyant_tethys">
+    <scene>
+      <!-- For turquoise ambient -->
+      <ambient>0.0 1.0 1.0</ambient>
+      <background>0.0 0.7 0.8</background>
+    </scene>
+
+    <physics name="1ms" type="ode">
+      <max_step_size>0.001</max_step_size>
+      <real_time_factor>1.0</real_time_factor>
+    </physics>
+    <plugin
+      filename="ignition-gazebo-physics-system"
+      name="ignition::gazebo::systems::Physics">
+    </plugin>
+    <plugin
+      filename="ignition-gazebo-user-commands-system"
+      name="ignition::gazebo::systems::UserCommands">
+    </plugin>
+    <plugin
+      filename="ignition-gazebo-scene-broadcaster-system"
+      name="ignition::gazebo::systems::SceneBroadcaster">
+    </plugin>
+    <plugin
+      filename="ignition-gazebo-contact-system"
+      name="ignition::gazebo::systems::Contact">
+    </plugin>
+
+    <plugin
+      filename="ignition-gazebo-buoyancy-system"
+      name="ignition::gazebo::systems::Buoyancy">
+      <uniform_fluid_density>1000</uniform_fluid_density>
+    </plugin>
+
+    <light type="directional" name="sun">
+      <cast_shadows>true</cast_shadows>
+      <pose>0 0 10 0 0 0</pose>
+      <diffuse>1 1 1 1</diffuse>
+      <specular>0.5 0.5 0.5 1</specular>
+      <attenuation>
+        <range>1000</range>
+        <constant>0.9</constant>
+        <linear>0.01</linear>
+        <quadratic>0.001</quadratic>
+      </attenuation>
+      <direction>-0.5 0.1 -0.9</direction>
+    </light>
+
+    <model name="buoyant_box">
+      <pose>0 0 0 0 0 0</pose>
+      <link name='body'>
+        <inertial>
+          <mass>1000</mass>
+          <inertia>
+            <ixx>133.3333</ixx>
+            <iyy>133.3333</iyy>
+            <izz>133.3333</izz>
+          </inertia>
+        </inertial>
+        <visual name='body_visual'>
+          <geometry>
+            <box>
+              <size>1 1 1</size>
+            </box>
+          </geometry>
+        </visual>
+        <collision name='body_collision'>
+          <geometry>
+            <box>
+              <size>1 1 1</size>
+            </box>
+          </geometry>
+        </collision>
+      </link>
+      <plugin
+        filename="libignition-gazebo-buoyancy-engine-system.so"
+        name="ignition::gazebo::systems::BuoyancyEngine">
+        <link_name>body</link_name>
+        <namespace>buoyant_box</namespace>
+        <min_volume>0.0</min_volume>
+        <neutral_volume>0.002</neutral_volume>
+        <default_volume>0.002</default_volume>
+        <max_volume>0.003</max_volume>
+        <max_inflation_rate>0.0003</max_inflation_rate>
+      </plugin>
+
+    </model>
+  </world>
+</sdf>
diff --git a/src/systems/CMakeLists.txt b/src/systems/CMakeLists.txt
index 2e2f830236..e63c1ccd86 100644
--- a/src/systems/CMakeLists.txt
+++ b/src/systems/CMakeLists.txt
@@ -92,6 +92,7 @@ add_subdirectory(apply_joint_force)
 add_subdirectory(battery_plugin)
 add_subdirectory(breadcrumbs)
 add_subdirectory(buoyancy)
+add_subdirectory(buoyancy_engine)
 add_subdirectory(collada_world_exporter)
 add_subdirectory(contact)
 add_subdirectory(camera_video_recorder)
diff --git a/src/systems/buoyancy_engine/BuoyancyEngine.cc b/src/systems/buoyancy_engine/BuoyancyEngine.cc
new file mode 100644
index 0000000000..14131f6c2d
--- /dev/null
+++ b/src/systems/buoyancy_engine/BuoyancyEngine.cc
@@ -0,0 +1,249 @@
+/*
+ * Copyright (C) 2021 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <algorithm>
+#include <chrono>
+#include <memory>
+#include <mutex>
+#include <string>
+
+#include <ignition/gazebo/components/Gravity.hh>
+#include <ignition/gazebo/components/World.hh>
+#include <ignition/gazebo/Link.hh>
+#include <ignition/msgs/double.pb.h>
+#include <ignition/plugin/Register.hh>
+#include <ignition/transport/Node.hh>
+
+#include "BuoyancyEngine.hh"
+
+using namespace ignition;
+using namespace gazebo;
+using namespace systems;
+
+class ignition::gazebo::systems::BuoyancyEnginePrivateData
+{
+  /// \brief Callback for incoming commands
+  /// \param[in] _volumeSetPoint - ignition message containing the desired
+  /// volume (in m^3) to fill/drain bladder to.
+  public: void OnCmdBuoyancyEngine(
+    const ignition::msgs::Double &_volumeSetPoint);
+
+  /// \brief Current volume of bladder in m^3
+  public: double bladderVolume = 3e-5;
+
+  /// \brief Maximum inflation rate in m^3*s^-1
+  public: double maxInflationRate = 3e-6;
+
+  /// \brief Set-point for volume, in m^3
+  public: double volumeSetPoint = 0.000030;
+
+  /// \brief Minimum volume of bladder in m^3
+  public: double minVolume = 0.000030;
+
+  /// \brief Maximum volume of bladder in m^3
+  public: double maxVolume = 0.000990;
+
+  /// \brief The link which the bladder is attached to
+  public: ignition::gazebo::Entity linkEntity{kNullEntity};
+
+  /// \brief The world entity
+  public: Entity world{kNullEntity};
+
+  /// \brief The fluid density in kg*m^-3
+  public: double fluidDensity = 1000;
+
+  /// \brief The neutral volume in m^3
+  public: double neutralVolume = 0.0003;
+
+  /// \brief Trasport node for control
+  public: ignition::transport::Node node;
+
+  /// \brief Publishes bladder status
+  public: ignition::transport::Node::Publisher statusPub;
+
+  /// \brief mutex for protecting bladder volume and set point.
+  public: std::mutex mtx;
+};
+
+//////////////////////////////////////////////////
+void BuoyancyEnginePrivateData::OnCmdBuoyancyEngine(
+  const ignition::msgs::Double &_volumeSetpoint)
+{
+  auto volume = std::max(this->minVolume, _volumeSetpoint.data());
+  volume = std::min(volume, this->maxVolume);
+
+  std::lock_guard lock(this->mtx);
+  this->volumeSetPoint = volume;
+}
+
+//////////////////////////////////////////////////
+BuoyancyEnginePlugin::BuoyancyEnginePlugin()
+  : dataPtr(std::make_unique<BuoyancyEnginePrivateData>())
+{
+}
+
+//////////////////////////////////////////////////
+void BuoyancyEnginePlugin::Configure(
+  const ignition::gazebo::Entity &_entity,
+  const std::shared_ptr<const sdf::Element> &_sdf,
+  ignition::gazebo::EntityComponentManager &_ecm,
+  ignition::gazebo::EventManager &/*_eventMgr*/)
+{
+  auto model = ignition::gazebo::Model(_entity);
+  if (!_sdf->HasElement("link_name"))
+  {
+    ignerr << "Buoyancy Engine must be attached to some link."  << std::endl;
+    return;
+  }
+
+  this->dataPtr->linkEntity =
+    model.LinkByName(_ecm, _sdf->Get<std::string>("link_name"));
+  if (this->dataPtr->linkEntity == kNullEntity)
+  {
+    ignerr << "Link [" << _sdf->Get<std::string>("link_name")
+      << "] was not found in model [" << model.Name(_ecm) << "]" << std::endl;
+    return;
+  }
+
+  if (_sdf->HasElement("min_volume"))
+  {
+    this->dataPtr->minVolume = _sdf->Get<double>("min_volume");
+  }
+
+  if (_sdf->HasElement("max_volume"))
+  {
+    this->dataPtr->maxVolume = _sdf->Get<double>("max_volume");
+  }
+
+  if (_sdf->HasElement("fluid_density"))
+  {
+    this->dataPtr->fluidDensity = _sdf->Get<double>("fluid_density");
+  }
+
+  this->dataPtr->bladderVolume = this->dataPtr->minVolume;
+  if (_sdf->HasElement("default_volume"))
+  {
+    this->dataPtr->bladderVolume = _sdf->Get<double>("default_volume");
+    this->dataPtr->volumeSetPoint = this->dataPtr->bladderVolume;
+  }
+
+  if (_sdf->HasElement("neutral_volume"))
+  {
+    this->dataPtr->neutralVolume = _sdf->Get<double>("neutral_volume");
+  }
+
+  if(_sdf->HasElement("max_inflation_rate"))
+  {
+    this->dataPtr->maxInflationRate = _sdf->Get<double>("max_inflation_rate");
+  }
+
+  this->dataPtr->world = _ecm.EntityByComponents(components::World());
+  if (this->dataPtr->world == kNullEntity)
+  {
+    ignerr << "World entity not found" <<std::endl;
+    return;
+  }
+
+  std::string cmdTopic = "/buoyancy_engine/";
+  std::string statusTopic = "/buoyancy_engine/current_volume";
+  if (_sdf->HasElement("namespace"))
+  {
+    cmdTopic = ignition::transport::TopicUtils::AsValidTopic(
+      "/model/" + _sdf->Get<std::string>("namespace") + "/buoyancy_engine/");
+    statusTopic = ignition::transport::TopicUtils::AsValidTopic(
+      "/model/" + _sdf->Get<std::string>("namespace")
+      + "/buoyancy_engine/current_volume");
+  }
+
+  if(!this->dataPtr->node.Subscribe(cmdTopic,
+    &BuoyancyEnginePrivateData::OnCmdBuoyancyEngine, this->dataPtr.get()))
+  {
+    ignerr << "Failed to subscribe to [" << cmdTopic << "]" << std::endl;
+  }
+
+  this->dataPtr->statusPub =
+    this->dataPtr->node.Advertise<ignition::msgs::Double>(statusTopic);
+
+  igndbg << "Listening to commands on [" << cmdTopic
+         << "], publishing status on [" << statusTopic << "]" <<std::endl;
+}
+
+//////////////////////////////////////////////////
+void BuoyancyEnginePlugin::PreUpdate(
+  const ignition::gazebo::UpdateInfo &_info,
+  ignition::gazebo::EntityComponentManager &_ecm)
+{
+  if (_info.paused)
+    return;
+
+  typedef std::chrono::duration<float, std::ratio<1L, 1L>> DurationInSecs;
+  auto dt = std::chrono::duration_cast<DurationInSecs>(_info.dt).count();
+
+  ignition::msgs::Double msg;
+
+  const components::Gravity *gravity = _ecm.Component<components::Gravity>(
+    this->dataPtr->world);
+  if (!gravity)
+  {
+    ignerr << "World has no gravity component" << std::endl;
+    return;
+  }
+
+  math::Vector3d zForce;
+  {
+    std::lock_guard lock(this->dataPtr->mtx);
+    // Adjust the bladder volume using the pump. Assume ability to pump at
+    // max flow rate
+    if (this->dataPtr->bladderVolume < this->dataPtr->volumeSetPoint)
+    {
+      this->dataPtr->bladderVolume +=
+        std::min(
+          dt * this->dataPtr->maxInflationRate,
+          this->dataPtr->volumeSetPoint - this->dataPtr->bladderVolume
+        );
+    }
+    else if (this->dataPtr->bladderVolume > this->dataPtr->volumeSetPoint)
+    {
+      this->dataPtr->bladderVolume -=
+        std::min(
+          dt * this->dataPtr->maxInflationRate,
+          this->dataPtr->bladderVolume - this->dataPtr->volumeSetPoint
+        );
+    }
+
+    /// Populate status message
+    msg.set_data(this->dataPtr->bladderVolume);
+    this->dataPtr->statusPub.Publish(msg);
+
+    // Simply use Archimede's principle to apply a force at the desired link
+    // position. We take off the neutral buoyancy element in order to simulate
+    // the mass of the oil in the bladder.
+    zForce = - gravity->Data() * this->dataPtr->fluidDensity
+      * (this->dataPtr->bladderVolume - this->dataPtr->neutralVolume);
+  }
+  ignition::gazebo::Link link(this->dataPtr->linkEntity);
+  link.AddWorldWrench(_ecm, zForce, {0, 0, 0});
+}
+
+IGNITION_ADD_PLUGIN(
+  BuoyancyEnginePlugin,
+  ignition::gazebo::System,
+  BuoyancyEnginePlugin::ISystemConfigure,
+  BuoyancyEnginePlugin::ISystemPreUpdate)
+
+IGNITION_ADD_PLUGIN_ALIAS(BuoyancyEnginePlugin,
+                          "ignition::gazebo::systems::BuoyancyEngine")
diff --git a/src/systems/buoyancy_engine/BuoyancyEngine.hh b/src/systems/buoyancy_engine/BuoyancyEngine.hh
new file mode 100644
index 0000000000..c4dd70cf80
--- /dev/null
+++ b/src/systems/buoyancy_engine/BuoyancyEngine.hh
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2021 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+#ifndef IGNITION_GAZEBO_SYSTEMS_BUOYANCYENGINE_HH_
+#define IGNITION_GAZEBO_SYSTEMS_BUOYANCYENGINE_HH_
+
+#include <ignition/gazebo/System.hh>
+
+#include <memory>
+
+namespace ignition
+{
+namespace gazebo
+{
+// Inline bracket to help doxygen filtering.
+inline namespace IGNITION_GAZEBO_VERSION_NAMESPACE {
+namespace systems
+{
+  class BuoyancyEnginePrivateData;
+
+  /// \brief This class provides a simple mechanical bladder which is used to
+  /// control the buoyancy of an underwater glider. It uses Archimedes'
+  /// principle to apply an upward force based on the volume of the bladder. It
+  /// listens to the topic `buoyancy_engine` or
+  /// `/model/{namespace}/buoyancy_engine` topic for the volume of the bladder
+  /// in *cubicmeters*.
+  ///
+  /// ## Parameters
+  /// <link_name> - The link which the plugin is attached to [required, string]
+  /// <namespace> - The namespace for the topic. If empty the plugin will listen
+  ///   on `buoyancy_engine` otherwise it listens on
+  ///   `/model/{namespace}/buoyancy_engine` [optional, string]
+  /// <min_volume> - Minimum volume of the engine [optional, float,
+  ///   default=0.00003m^3]
+  /// <neutral_volume> - At this volume the engine has neutral buoyancy. Used to
+  ///   estimate the weight of the engine [optional, float, default=0.0003m^3]
+  /// <default_volume> - The volume which the engine starts at [optional, float,
+  ///   default=0.0003m^3]
+  /// <max_volume> - Maximum volume of the engine [optional, float,
+  ///   default=0.00099m^3]
+  /// <max_inflation_rate> - Maximum inflation rate for bladder [optional,
+  ///   float, default=0.000003m^3/s]
+  /// <fluid_density> - The fluid density of the liquid its suspended in kgm^-3.
+  ///   [optional, float, default=1000kgm^-3]
+  ///
+  /// ## Topics
+  /// * Subscribes to a ignition::msgs::Double on `buoyancy_engine` or
+  ///  `/model/{namespace}/buoyancy_engine`. This is the set point for the
+  ///  engine.
+  /// * Publishes a ignition::msgs::Double on `buoyancy_engine` or
+  ///  `/model/{namespace}/buoyancy_engine/current_volume` on the current volume
+  ///
+  /// ## Examples
+  /// To get started run:
+  /// ```
+  /// ign gazebo buoyancy_engine.sdf
+  /// ```
+  /// Enter the following in a separate terminal:
+  /// ```
+  /// ign topic -t  /model/buoyant_box/buoyancy_engine/ -m ignition.msgs.Double
+  ///    -p "data: 0.003"
+  /// ```
+  /// To see the box float up.
+  /// ```
+  /// ign topic -t  /model/buoyant_box/buoyancy_engine/ -m ignition.msgs.Double
+  ///    -p "data: 0.001"
+  /// ```
+  /// To see the box go down.
+  /// To see the current volume enter:
+  /// ```
+  /// ign topic -t  /model/buoyant_box/buoyancy_engine/current_volume -e
+  /// ```
+  class BuoyancyEnginePlugin:
+    public ignition::gazebo::System,
+    public ignition::gazebo::ISystemConfigure,
+    public ignition::gazebo::ISystemPreUpdate
+  {
+    /// \brief Constructor
+    public: BuoyancyEnginePlugin();
+
+    // Documentation inherited
+    public: void Configure(
+        const ignition::gazebo::Entity &_entity,
+        const std::shared_ptr<const sdf::Element> &_sdf,
+        ignition::gazebo::EntityComponentManager &_ecm,
+        ignition::gazebo::EventManager &/*_eventMgr*/
+    );
+
+    // Documentation inherited
+    public: void PreUpdate(
+        const ignition::gazebo::UpdateInfo &_info,
+        ignition::gazebo::EntityComponentManager &_ecm);
+
+    /// \brief Private data pointer
+    private: std::unique_ptr<BuoyancyEnginePrivateData> dataPtr;
+  };
+}
+}
+}
+}
+#endif
diff --git a/src/systems/buoyancy_engine/CMakeLists.txt b/src/systems/buoyancy_engine/CMakeLists.txt
new file mode 100644
index 0000000000..b849e89309
--- /dev/null
+++ b/src/systems/buoyancy_engine/CMakeLists.txt
@@ -0,0 +1,7 @@
+gz_add_system(buoyancy-engine
+  SOURCES
+  BuoyancyEngine.cc
+  PUBLIC_LINK_LIBS
+    ignition-common${IGN_COMMON_VER}::ignition-common${IGN_COMMON_VER}
+    ignition-transport${IGN_TRANSPORT_VER}::ignition-transport${IGN_TRANSPORT_VER}
+)
diff --git a/test/integration/CMakeLists.txt b/test/integration/CMakeLists.txt
index 9753c3ef2c..d4fb16a10a 100644
--- a/test/integration/CMakeLists.txt
+++ b/test/integration/CMakeLists.txt
@@ -8,6 +8,7 @@ set(tests
   battery_plugin.cc
   breadcrumbs.cc
   buoyancy.cc
+  buoyancy_engine.cc
   collada_world_exporter.cc
   components.cc
   contact_system.cc
diff --git a/test/integration/buoyancy_engine.cc b/test/integration/buoyancy_engine.cc
new file mode 100644
index 0000000000..822666d22c
--- /dev/null
+++ b/test/integration/buoyancy_engine.cc
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2021 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <gtest/gtest.h>
+
+#include <ignition/common/Console.hh>
+#include <ignition/common/Util.hh>
+#include <ignition/msgs/double.pb.h>
+#include <ignition/transport/Node.hh>
+
+#include "ignition/gazebo/Server.hh"
+#include "ignition/gazebo/SystemLoader.hh"
+#include "ignition/gazebo/components/Name.hh"
+#include "ignition/gazebo/components/Pose.hh"
+#include "ignition/gazebo/components/Model.hh"
+
+#include "ignition/gazebo/test_config.hh"
+#include "../helpers/Relay.hh"
+#include "../helpers/EnvTestFixture.hh"
+
+using namespace ignition;
+using namespace gazebo;
+
+class BuoyancyEngineTest : public InternalFixture<::testing::Test>
+{
+  // Documentation inherited
+  protected: void SetUp() override
+  {
+    InternalFixture::SetUp();
+    this->pub = this->node.Advertise<ignition::msgs::Double>(
+      "/model/buoyant_box/buoyancy_engine/");
+  }
+
+  /// \brief Node for communication
+  public: ignition::transport::Node node;
+
+  /// \brief Publishes commands
+  public: ignition::transport::Node::Publisher pub;
+};
+
+/////////////////////////////////////////////////
+TEST_F(BuoyancyEngineTest, TestDownward)
+{
+  ServerConfig serverConfig;
+  const auto sdfFile = common::joinPaths(std::string(PROJECT_SOURCE_PATH),
+    "test", "worlds", "buoyancy_engine.sdf");
+  serverConfig.SetSdfFile(sdfFile);
+
+  Server server(serverConfig);
+  EXPECT_FALSE(server.Running());
+  EXPECT_FALSE(*server.Running(0));
+
+  using namespace std::chrono_literals;
+  server.SetUpdatePeriod(1ns);
+
+  std::size_t iterations = 10000;
+
+  test::Relay testSystem;
+  std::vector<ignition::math::Pose3d> poses;
+
+  testSystem.OnPostUpdate([&](const gazebo::UpdateInfo &/*_info*/,
+                             const gazebo::EntityComponentManager &_ecm)
+  {
+    // Check pose
+    Entity buoyantBox = _ecm.EntityByComponents(
+      components::Model(), components::Name("buoyant_box"));
+    EXPECT_NE(kNullEntity, buoyantBox);
+
+    auto submarineBuoyantPose = _ecm.Component<components::Pose>(buoyantBox);
+    EXPECT_NE(submarineBuoyantPose, nullptr);
+    if (submarineBuoyantPose == nullptr)
+    {
+      ignerr << "Unable to get pose" <<std::endl;
+      return;
+    }
+    poses.push_back(submarineBuoyantPose->Data());
+  });
+
+  server.AddSystem(testSystem.systemPtr);
+  ignition::msgs::Double volume;
+  volume.set_data(0);
+  this->pub.Publish(volume);
+  server.Run(true, iterations, false);
+
+  EXPECT_LT(poses.rbegin()->Pos().Z(), poses.begin()->Pos().Z());
+  EXPECT_NEAR(poses.rbegin()->Pos().X(), poses.begin()->Pos().X(), 1e-3);
+  EXPECT_NEAR(poses.rbegin()->Pos().Y(), poses.begin()->Pos().Y(), 1e-3);
+}
+
+/////////////////////////////////////////////////
+TEST_F(BuoyancyEngineTest, TestUpward)
+{
+  ServerConfig serverConfig;
+  const auto sdfFile = std::string(PROJECT_SOURCE_PATH) +
+    "/test/worlds/buoyancy_engine.sdf";
+  serverConfig.SetSdfFile(sdfFile);
+
+  Server server(serverConfig);
+  EXPECT_FALSE(server.Running());
+  EXPECT_FALSE(*server.Running(0));
+
+  using namespace std::chrono_literals;
+  server.SetUpdatePeriod(1ns);
+
+  std::size_t iterations = 10000;
+
+  test::Relay testSystem;
+  std::vector<ignition::math::Pose3d> poses;
+
+  testSystem.OnPostUpdate([&](const gazebo::UpdateInfo &/*_info*/,
+                             const gazebo::EntityComponentManager &_ecm)
+  {
+    // Check pose
+    Entity buoyantBox = _ecm.EntityByComponents(
+      components::Model(), components::Name("buoyant_box"));
+    EXPECT_NE(kNullEntity, buoyantBox);
+
+    auto submarineBuoyantPose = _ecm.Component<components::Pose>(buoyantBox);
+    EXPECT_NE(submarineBuoyantPose, nullptr);
+    if (submarineBuoyantPose == nullptr)
+    {
+      ignerr << "Unable to get pose" <<std::endl;
+      return;
+    }
+    poses.push_back(submarineBuoyantPose->Data());
+  });
+
+  server.AddSystem(testSystem.systemPtr);
+  ignition::msgs::Double volume;
+  volume.set_data(10);
+  this->pub.Publish(volume);
+  server.Run(true, iterations, false);
+
+  EXPECT_GT(poses.rbegin()->Pos().Z(), poses.begin()->Pos().Z());
+  EXPECT_NEAR(poses.rbegin()->Pos().X(), poses.begin()->Pos().X(), 1e-3);
+  EXPECT_NEAR(poses.rbegin()->Pos().Y(), poses.begin()->Pos().Y(), 1e-3);
+}
+
diff --git a/test/worlds/buoyancy_engine.sdf b/test/worlds/buoyancy_engine.sdf
new file mode 100644
index 0000000000..51ce5897ba
--- /dev/null
+++ b/test/worlds/buoyancy_engine.sdf
@@ -0,0 +1,72 @@
+<?xml version="1.0" ?>
+<sdf version="1.6">
+  <world name="buoyant_tethys">
+    <physics name="1ms" type="ode">
+      <max_step_size>0.001</max_step_size>
+      <real_time_factor>1.0</real_time_factor>
+    </physics>
+    <plugin
+      filename="ignition-gazebo-physics-system"
+      name="ignition::gazebo::systems::Physics">
+    </plugin>
+    <plugin
+      filename="ignition-gazebo-buoyancy-system"
+      name="ignition::gazebo::systems::Buoyancy">
+      <uniform_fluid_density>1000</uniform_fluid_density>
+    </plugin>
+
+    <light type="directional" name="sun">
+      <cast_shadows>true</cast_shadows>
+      <pose>0 0 10 0 0 0</pose>
+      <diffuse>1 1 1 1</diffuse>
+      <specular>0.5 0.5 0.5 1</specular>
+      <attenuation>
+        <range>1000</range>
+        <constant>0.9</constant>
+        <linear>0.01</linear>
+        <quadratic>0.001</quadratic>
+      </attenuation>
+      <direction>-0.5 0.1 -0.9</direction>
+    </light>
+
+    <model name="buoyant_box">
+      <pose>0 0 0 0 0 0</pose>
+      <link name='body'>
+        <inertial>
+          <mass>1000</mass>
+          <inertia>
+            <ixx>133.3333</ixx>
+            <iyy>133.3333</iyy>
+            <izz>133.3333</izz>
+          </inertia>
+        </inertial>
+        <visual name='body_visual'>
+          <geometry>
+            <box>
+              <size>1 1 1</size>
+            </box>
+          </geometry>
+        </visual>
+        <collision name='body_collision'>
+          <geometry>
+            <box>
+              <size>1 1 1</size>
+            </box>
+          </geometry>
+        </collision>
+      </link>
+      <plugin
+        filename="libignition-gazebo-buoyancy-engine-system.so"
+        name="ignition::gazebo::systems::BuoyancyEngine">
+        <link_name>body</link_name>
+        <namespace>buoyant_box</namespace>
+        <min_volume>0.001</min_volume>
+        <neutral_volume>0.002</neutral_volume>
+        <default_volume>0.002</default_volume>
+        <max_volume>0.003</max_volume>
+        <max_inflation_rate>0.0003</max_inflation_rate>
+      </plugin>
+
+    </model>
+  </world>
+</sdf>