diff --git a/client/src/main/java/ru/trader/Main.java b/client/src/main/java/ru/trader/Main.java
index 379c1c8..bcbf8e6 100644
--- a/client/src/main/java/ru/trader/Main.java
+++ b/client/src/main/java/ru/trader/Main.java
@@ -119,6 +119,7 @@ public class Main extends Application {
         Screeners.loadHelperStage(getUrl("helper.fxml"));
         Screeners.loadVendorFilterStage(getUrl("vFilter.fxml"));
         Screeners.loadDBEditorStage(getUrl("db/dbeditor.fxml"));
+        Screeners.loadEngineModStage(getUrl("engineMod.fxml"));
     }
 
     private static URL getUrl(String filename) throws MalformedURLException {
diff --git a/client/src/main/java/ru/trader/controllers/EngineModController.java b/client/src/main/java/ru/trader/controllers/EngineModController.java
new file mode 100644
index 0000000..38e38d1
--- /dev/null
+++ b/client/src/main/java/ru/trader/controllers/EngineModController.java
@@ -0,0 +1,58 @@
+package ru.trader.controllers;
+
+import javafx.collections.FXCollections;
+import javafx.fxml.FXML;
+import javafx.scene.Parent;
+import javafx.scene.control.ComboBox;
+import javafx.scene.control.Dialog;
+import ru.trader.core.Engine;
+import ru.trader.core.ModEngine;
+import ru.trader.model.MarketModel;
+import ru.trader.view.support.EngineStringConverter;
+import ru.trader.view.support.Localization;
+import ru.trader.view.support.NumberField;
+
+import java.util.Optional;
+
+public class EngineModController {
+    @FXML
+    private ComboBox<Engine> type;
+    @FXML
+    private NumberField optMass;
+
+    private Dialog<Engine> dlg;
+    private MarketModel market;
+
+    @FXML
+    private void initialize() {
+        type.setItems(FXCollections.observableArrayList(Engine.getEngines()));
+        type.setConverter(new EngineStringConverter());
+        type.getSelectionModel().selectFirst();
+        optMass.setValue(0.0);
+    }
+
+    private void createDialog(Parent owner, Parent content){
+        dlg = new Dialog<>();
+        if (owner != null) dlg.initOwner(owner.getScene().getWindow());
+        dlg.setTitle(Localization.getString("dialog.engine.title"));
+        dlg.getDialogPane().setContent(content);
+        dlg.getDialogPane().getButtonTypes().addAll(Dialogs.OK, Dialogs.CANCEL);
+        dlg.setResultConverter(dialogButton -> {
+            if (dialogButton == Dialogs.OK) {
+                return new ModEngine(type.getValue(), optMass.getValue().doubleValue());
+            }
+            return null;
+        });
+        dlg.setResizable(false);
+    }
+
+
+    public Optional<Engine> showDialog(Parent parent, Parent content) {
+        if (dlg == null){
+            createDialog(parent, content);
+        }
+        return dlg.showAndWait();
+    }
+
+
+}
diff --git a/client/src/main/java/ru/trader/controllers/ProfileController.java b/client/src/main/java/ru/trader/controllers/ProfileController.java
index e54dac4..485eab0 100644
--- a/client/src/main/java/ru/trader/controllers/ProfileController.java
+++ b/client/src/main/java/ru/trader/controllers/ProfileController.java
@@ -8,18 +8,19 @@ import javafx.fxml.FXML;
 import javafx.scene.Node;
 import javafx.scene.control.*;
 import javafx.scene.layout.Pane;
-import javafx.util.StringConverter;
 import ru.trader.Main;
 import ru.trader.ServicesManager;
 import ru.trader.core.Engine;
 import ru.trader.model.*;
 import ru.trader.model.support.ChangeMarketListener;
+import ru.trader.view.support.EngineStringConverter;
 import ru.trader.view.support.NumberField;
 import ru.trader.view.support.ViewUtils;
 import ru.trader.view.support.autocomplete.AutoCompletion;
 import ru.trader.view.support.autocomplete.CachedSuggestionProvider;
 import ru.trader.view.support.autocomplete.SystemsProvider;
 
+import java.util.Optional;
 
 
 public class ProfileController {
@@ -198,6 +199,14 @@ public class ProfileController {
         return s == null ? ModelFabric.NONE_STATION : s.get(name);
     }
 
+    @FXML
+    private void modEngine(){
+        Optional<Engine> engine = Screeners.showModEngine();
+        if (engine.isPresent()){
+            this.engine.setValue(engine.get());
+        }
+    }
+
     private void updateIcons(){
         SystemModel s = system.getValue();
         if (!s.isCorrect()){
@@ -272,16 +281,4 @@ public class ProfileController {
         }
     };
 
-    private class EngineStringConverter extends StringConverter<Engine> {
-        @Override
-        public String toString(Engine engine) {
-            return ""+engine.getClazz()+engine.getRating();
-        }
-
-        @Override
-        public Engine fromString(String string) {
-            throw new UnsupportedOperationException();
-        }
-    }
-
 }
diff --git a/client/src/main/java/ru/trader/controllers/Screeners.java b/client/src/main/java/ru/trader/controllers/Screeners.java
index 60675e8..d8c3916 100644
--- a/client/src/main/java/ru/trader/controllers/Screeners.java
+++ b/client/src/main/java/ru/trader/controllers/Screeners.java
@@ -12,6 +12,7 @@ import javafx.scene.layout.Priority;
 import javafx.stage.Stage;
 import javafx.util.Pair;
 import ru.trader.EMDNUpdater;
+import ru.trader.core.Engine;
 import ru.trader.core.MarketFilter;
 import ru.trader.core.VendorFilter;
 import ru.trader.db.controllers.DBEditorController;
@@ -42,6 +43,7 @@ public class Screeners {
     private static Parent helperScreen;
     private static Parent vFilterScreen;
     private static Parent dbEditorScreen;
+    private static Parent engineModScreen;
 
     private static MainController mainController;
     private static ItemDescController itemDescController;
@@ -57,6 +59,7 @@ public class Screeners {
     private static HelperController helperController;
     private static VendorFilterController vFilterController;
     private static DBEditorController dbEditorController;
+    private static EngineModController engineModController;
 
     private static FXMLLoader initLoader(URL url){
         FXMLLoader loader = new FXMLLoader(url, Localization.getResources());
@@ -174,6 +177,13 @@ public class Screeners {
         dbEditorController = loader.getController();
     }
 
+    public static void loadEngineModStage(URL fxml) throws IOException {
+        FXMLLoader loader =  initLoader(fxml);
+        engineModScreen = loader.load();
+        addStylesheet(engineModScreen);
+        engineModController = loader.getController();
+    }
+
     public static void show(Node node){
         mainController.getMainPane().setCenter(node);
     }
@@ -348,6 +358,10 @@ public class Screeners {
         return vFilterController.showEditDialog(mainScreen, vFilterScreen, filter);
     }
 
+    public static Optional<Engine> showModEngine(){
+        return engineModController.showDialog(mainScreen, engineModScreen);
+    }
+
     public static void reinitAll() {
         mainController.init();
         systemsEditorController.init();
diff --git a/client/src/main/java/ru/trader/view/support/EngineStringConverter.java b/client/src/main/java/ru/trader/view/support/EngineStringConverter.java
new file mode 100644
index 0000000..f87c18d
--- /dev/null
+++ b/client/src/main/java/ru/trader/view/support/EngineStringConverter.java
@@ -0,0 +1,17 @@
+package ru.trader.view.support;
+
+import javafx.util.StringConverter;
+import ru.trader.core.Engine;
+import ru.trader.core.ModEngine;
+
+public class EngineStringConverter extends StringConverter<Engine> {
+    @Override
+    public String toString(Engine engine) {
+        return engine instanceof ModEngine ? "Custom" : ""+engine.getClazz()+engine.getRating();
+    }
+
+    @Override
+    public Engine fromString(String string) {
+        throw new UnsupportedOperationException();
+    }
+}
\ No newline at end of file
diff --git a/client/src/main/resources/lang/locale_en_US.properties b/client/src/main/resources/lang/locale_en_US.properties
index f39091f..0945675 100644
--- a/client/src/main/resources/lang/locale_en_US.properties
+++ b/client/src/main/resources/lang/locale_en_US.properties
@@ -111,6 +111,11 @@ dialog.group.title=Adding new group
 dialog.group.id=ID:
 dialog.group.type=Type:
 
+#engine mod dialog
+dialog.engine.title=Engine modification
+dialog.engine.class=Engine class:
+dialog.engine.optMass=Optimal mass:
+
 #profile.fxml
 profile.name=Cmdr:
 profile.balance=Balance:
diff --git a/client/src/main/resources/lang/locale_ru_RU.properties b/client/src/main/resources/lang/locale_ru_RU.properties
index b8b314c..b11bd4d 100644
--- a/client/src/main/resources/lang/locale_ru_RU.properties
+++ b/client/src/main/resources/lang/locale_ru_RU.properties
@@ -111,6 +111,10 @@ dialog.item.group=\u0413\u0440\u0443\u043F\u043F\u0430:
 dialog.group.title=\u0414\u043E\u0431\u0430\u0432\u043B\u0435\u043D\u0438\u0435 \u043D\u043E\u0432\u043E\u0439 \u0433\u0440\u0443\u043F\u043F\u044B
 dialog.group.id=ID:
 dialog.group.type=\u0422\u0438\u043F:
+#engine mod dialog
+dialog.engine.title=\u041C\u043E\u0434\u0438\u0444\u0438\u043A\u0430\u0446\u0438\u044F \u0434\u0432\u0438\u0433\u0430\u0442\u0435\u043B\u044F
+dialog.engine.class=\u041A\u043B\u0430\u0441\u0441 \u0434\u0432\u0438\u0433\u0430\u0442\u0435\u043B\u044F:
+dialog.engine.optMass=\u041E\u043F\u0442\u0438\u043C\u0430\u043B\u044C\u043D\u0430\u044F \u043C\u0430\u0441\u0441\u0430:
 
 #profile.fxml
 profile.name=\u041A\u041C\u0414\u0420:
diff --git a/client/src/main/resources/view/engineMod.fxml b/client/src/main/resources/view/engineMod.fxml
new file mode 100644
index 0000000..17d665d
--- /dev/null
+++ b/client/src/main/resources/view/engineMod.fxml
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+
+<?import javafx.scene.control.ComboBox?>
+<?import javafx.scene.control.Label?>
+<?import javafx.scene.layout.HBox?>
+<?import ru.trader.view.support.NumberField?>
+<HBox xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1"
+      styleClass="dialog"
+      fx:controller="ru.trader.controllers.EngineModController" spacing="4">
+    <Label text="%dialog.engine.class"/>
+    <ComboBox fx:id="type" minWidth="60"/>
+    <Label text="%dialog.engine.optMass"/>
+    <NumberField fx:id="optMass" maxWidth="100" />
+
+</HBox>
diff --git a/client/src/main/resources/view/profile.fxml b/client/src/main/resources/view/profile.fxml
index f9d72a1..53039de 100644
--- a/client/src/main/resources/view/profile.fxml
+++ b/client/src/main/resources/view/profile.fxml
@@ -1,11 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<?import javafx.scene.control.*?>
-<?import javafx.scene.layout.HBox?>
-<?import javafx.scene.layout.StackPane?>
-<?import org.controlsfx.glyphfont.Glyph?>
-<?import ru.trader.view.support.NumberField?>
 <?import javafx.geometry.Insets?>
+<?import javafx.scene.control.*?>
+<?import javafx.scene.layout.*?>
+<?import org.controlsfx.glyphfont.*?>
+<?import ru.trader.view.support.NumberField?>
 <HBox xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1"
       fx:controller="ru.trader.controllers.ProfileController"
       spacing="4" >
@@ -40,18 +39,19 @@
             <Label text="%profile.ship.mass" />
             <NumberField fx:id="mass" maxWidth="60"/>
             <Label text="%profile.ship.engine" />
-            <ComboBox fx:id="engine" maxWidth="60"/>
+            <ComboBox fx:id="engine" maxWidth="100" minHeight="25"/>
+            <Button minWidth="30" minHeight="25" onAction="#modEngine"><graphic><Glyph text="FontAwesome|GEAR"/></graphic></Button>
             <Label text="%profile.ship.jump" />
             <Label fx:id="jumpRange"/>
         </HBox>
     </StackPane>
-    <ToggleButton minWidth="30" onAction="#toggleShipInfo">
+    <ToggleButton minWidth="30" minHeight="25" onAction="#toggleShipInfo">
         <graphic><Glyph text="FontAwesome|SPACE_SHUTTLE"/></graphic>
     </ToggleButton>
-    <ToggleButton fx:id="btnHelper" minWidth="30">
+    <ToggleButton fx:id="btnHelper" minWidth="30" minHeight="25">
         <graphic><Glyph text="FontAwesome|ROCKET"/></graphic>
     </ToggleButton>
-    <ToggleButton fx:id="btnEDCE" text="EDCE"/>
+    <ToggleButton fx:id="btnEDCE" text="EDCE" minHeight="25"/>
     <HBox HBox.hgrow="ALWAYS" alignment="CENTER_RIGHT">
         <Label fx:id="warningIcon" styleClass="icon-warning" prefWidth="30" prefHeight="30" visible="false">
             <graphic><Glyph text="FontAwesome|WARNING" /></graphic>
diff --git a/core/src/main/java/ru/trader/core/ModEngine.java b/core/src/main/java/ru/trader/core/ModEngine.java
new file mode 100644
index 0000000..841d30a
--- /dev/null
+++ b/core/src/main/java/ru/trader/core/ModEngine.java
@@ -0,0 +1,36 @@
+package ru.trader.core;
+
+import java.util.Objects;
+
+public class ModEngine extends Engine {
+    private final double optMass;
+
+    public ModEngine(int clazz, char rating) {
+        super(clazz, rating);
+        optMass = super.getOptMass();
+    }
+
+    public ModEngine(int clazz, char rating, double optMass) {
+        super(clazz, rating);
+        this.optMass = optMass;
+    }
+
+    public ModEngine(Engine engine, double optMass) {
+        super(engine.getClazz(), engine.getRating());
+        this.optMass = optMass;
+    }
+
+    @Override
+    public double getOptMass() {
+        return optMass;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof ModEngine)) return false;
+        if (!super.equals(o)) return false;
+        ModEngine modEngine = (ModEngine) o;
+        return Objects.equals(optMass, modEngine.optMass);
+    }
+}
diff --git a/core/src/main/java/ru/trader/core/Ship.java b/core/src/main/java/ru/trader/core/Ship.java
index a838465..37fd7aa 100644
--- a/core/src/main/java/ru/trader/core/Ship.java
+++ b/core/src/main/java/ru/trader/core/Ship.java
@@ -29,7 +29,7 @@ public class Ship {
     }
 
     public static Ship clone(Ship ship){
-        return ship != null ? new Ship(ship) : ship;
+        return ship != null ? new Ship(ship) : null;
     }
 
     public long getCargo() {
@@ -223,7 +223,12 @@ public class Ship {
         String e = values.getProperty("ship.engine","2E");
         Matcher matcher = ENGINE_REGEXP.matcher(e);
         if (matcher.find()){
-            ship.setEngine(Integer.valueOf(matcher.group(1)), matcher.group(2).charAt(0));
+            double optMass = Double.valueOf(values.getProperty("ship.engine.optmass", "-1"));
+            if (optMass != -1) {
+                ship.setEngine(new ModEngine(Integer.valueOf(matcher.group(1)), matcher.group(2).charAt(0), optMass));
+            } else {
+                ship.setEngine(Integer.valueOf(matcher.group(1)), matcher.group(2).charAt(0));
+            }
         }
         return ship;
     }
@@ -233,5 +238,10 @@ public class Ship {
         values.setProperty("ship.cargo", String.valueOf(cargo));
         values.setProperty("ship.tank", String.valueOf(tank));
         values.setProperty("ship.engine", String.valueOf(engine.getClazz()) + engine.getRating());
+        double optMass = -1;
+        if (engine instanceof ModEngine){
+            optMass = engine.getOptMass();
+        }
+        values.setProperty("ship.engine.optmass", String.valueOf(optMass));
     }
 }