diff --git a/lib/boatData/GwBoatData.h b/lib/boatData/GwBoatData.h
index 4c39689..5ffab7a 100644
--- a/lib/boatData/GwBoatData.h
+++ b/lib/boatData/GwBoatData.h
@@ -146,8 +146,10 @@ class GwBoatData{
     GWBOATDATA(double,MaxTws,4000,&formatKnots)
     GWBOATDATA(double,MaxAws,4000,&formatKnots)
     GWBOATDATA(double,AWA,4000,&formatWind)
-    GWBOATDATA(double,Heading,4000,&formatCourse)
+    GWBOATDATA(double,Heading,4000,&formatCourse) //true
+    GWBOATDATA(double,MagneticHeading,4000,&formatCourse)
     GWBOATDATA(double,Variation,4000,&formatCourse)
+    GWBOATDATA(double,Deviation,4000,&formatCourse)
     GWBOATDATA(double,RudderPosition,4000,&formatCourse)
     GWBOATDATA(double,Latitude,4000,NULL)
     GWBOATDATA(double,Longitude,4000,NULL)
diff --git a/lib/nmea0183ton2k/NMEA0183DataToN2K.cpp b/lib/nmea0183ton2k/NMEA0183DataToN2K.cpp
index 741df73..29157b6 100644
--- a/lib/nmea0183ton2k/NMEA0183DataToN2K.cpp
+++ b/lib/nmea0183ton2k/NMEA0183DataToN2K.cpp
@@ -345,6 +345,66 @@ private:
         }
     }
 
+    void convertHDM(const SNMEA0183Msg &msg){
+        double MagneticHeading=NMEA0183DoubleNA;
+        if (!NMEA0183ParseHDM_nc(msg, MagneticHeading))
+        {
+            logger->logDebug(GwLog::DEBUG, "failed to parse HDM %s", msg.line);
+            return;
+        }
+        if (! UD(MagneticHeading)) return;
+        tN2kMsg n2kMsg;
+        SetN2kMagneticHeading(n2kMsg,1,MagneticHeading,
+            boatData->Variation->getDataWithDefault(N2kDoubleNA),
+            boatData->Deviation->getDataWithDefault(N2kDoubleNA)
+        );
+        send(n2kMsg);    
+    }
+    
+    void convertHDT(const SNMEA0183Msg &msg){
+        double Heading=NMEA0183DoubleNA;
+        if (!NMEA0183ParseHDT_nc(msg, Heading))
+        {
+            logger->logDebug(GwLog::DEBUG, "failed to parse HDT %s", msg.line);
+            return;
+        }
+        if (! UD(Heading)) return;
+        tN2kMsg n2kMsg;
+        SetN2kTrueHeading(n2kMsg,1,Heading);
+        send(n2kMsg);    
+    }
+    void convertHDG(const SNMEA0183Msg &msg){
+        double MagneticHeading=NMEA0183DoubleNA;
+        double Variation=NMEA0183DoubleNA;
+        double Deviation=NMEA0183DoubleNA;
+        if (msg.FieldCount() < 5)
+        {
+            logger->logDebug(GwLog::DEBUG, "failed to parse HDG %s", msg.line);
+            return;
+        }
+        if (msg.FieldLen(0)>0){
+            MagneticHeading=formatDegToRad(atof(msg.Field(0)));
+        }
+        else{
+            return;
+        }
+        if (msg.FieldLen(1)>0){
+            Deviation=formatDegToRad(atof(msg.Field(1)));
+            if (msg.Field(2)[0] == 'W') Deviation=-Deviation;
+        }
+        if (msg.FieldLen(3)>0){
+            Variation=formatDegToRad(atof(msg.Field(3)));
+            if (msg.Field(4)[0] == 'W') Variation=-Variation;
+        }
+
+        if (! UD(MagneticHeading)) return;
+        UD(Variation);
+        UD(Deviation);
+        tN2kMsg n2kMsg;
+        SetN2kMagneticHeading(n2kMsg,1,MagneticHeading,Deviation,Variation);
+        send(n2kMsg);    
+    }
+
 //shortcut for lambda converters
 #define CVL [](const SNMEA0183Msg &msg, NMEA0183DataToN2KFunctions *p) -> void
     void registerConverters()
@@ -362,7 +422,16 @@ private:
             String(F("MWD")),&NMEA0183DataToN2KFunctions::convertMWD);     
         converters.registerConverter(
             130306UL,
-            String(F("VWR")),&NMEA0183DataToN2KFunctions::convertVWR);        
+            String(F("VWR")),&NMEA0183DataToN2KFunctions::convertVWR); 
+        converters.registerConverter(
+            127250UL,
+            String(F("HDM")),&NMEA0183DataToN2KFunctions::convertHDM); 
+        converters.registerConverter(
+            127250UL,
+            String(F("HDT")),&NMEA0183DataToN2KFunctions::convertHDT);
+        converters.registerConverter(
+            127250UL,
+            String(F("HDG")),&NMEA0183DataToN2KFunctions::convertHDG);                      
         unsigned long *aispgns=new unsigned long[7]{129810UL,129809UL,129040UL,129039UL,129802UL,129794UL,129038UL};
         converters.registerConverter(7,&aispgns[0],
             String(F("AIVDM")),&NMEA0183DataToN2KFunctions::convertAIVDX);
diff --git a/lib/nmea2kto0183/N2kDataToNMEA0183.cpp b/lib/nmea2kto0183/N2kDataToNMEA0183.cpp
index 04b2860..62a0330 100644
--- a/lib/nmea2kto0183/N2kDataToNMEA0183.cpp
+++ b/lib/nmea2kto0183/N2kDataToNMEA0183.cpp
@@ -122,20 +122,58 @@ private:
         double Variation;
         tNMEA0183Msg NMEA0183Msg;
         double Heading;
+        //if we have heading and variation we send HDG (mag.) and HDT
+        //if we have no variation we send either HDM or HDT
         if (ParseN2kHeading(N2kMsg, SID, Heading, _Deviation, Variation, ref))
         {
-            if (ref == N2khr_magnetic)
-            {
-                updateDouble(boatData->Variation, Variation); // Update Variation
-                if (!N2kIsNA(Heading) && boatData->Variation->isValid(millis()))
-                    Heading -= boatData->Variation->getData();
+            updateDouble(boatData->Variation,Variation);
+            updateDouble(boatData->Deviation,_Deviation);
+            if (N2kIsNA(Variation)){
+                //maybe we still have a valid variation
+                Variation=boatData->Variation->getDataWithDefault(N2kDoubleNA);
             }
-            updateDouble(boatData->Heading, Heading);
-            if (NMEA0183SetHDG(NMEA0183Msg, boatData->Heading->getDataWithDefault(NMEA0183DoubleNA), _Deviation, boatData->Variation->getDataWithDefault(NMEA0183DoubleNA)))
-            {
-                SendMessage(NMEA0183Msg);
+            if (N2kIsNA(Variation)){
+                //no variation
+                if (ref == N2khr_magnetic){
+                    updateDouble(boatData->MagneticHeading,Heading);
+                    if (NMEA0183SetHDM(NMEA0183Msg,Heading)){
+                        SendMessage(NMEA0183Msg);
+                    }    
+                }
+                if (ref == N2khr_true){
+                    updateDouble(boatData->Heading,Heading);
+                    if (NMEA0183SetHDT(NMEA0183Msg,Heading)){
+                        SendMessage(NMEA0183Msg);
+                    }
+                }
             }
+            else{
+                double MagneticHeading=N2kDoubleNA;
+                if (ref == N2khr_magnetic){
+                    MagneticHeading=Heading;
+                    Heading+=Variation;
+                }
+                if (ref == N2khr_true){
+                    MagneticHeading=Heading-Variation;
+                }
+                updateDouble(boatData->MagneticHeading,MagneticHeading);
+                updateDouble(boatData->Heading,Heading);
+                if (!N2kIsNA(MagneticHeading)){
+                    if (NMEA0183SetHDG(NMEA0183Msg, MagneticHeading,_Deviation, 
+                        Variation))
+                    {
+                        SendMessage(NMEA0183Msg);
+                    }
+                }
+                if (!N2kIsNA(Heading)){
+                    if (NMEA0183SetHDT(NMEA0183Msg, Heading))
+                    {
+                        SendMessage(NMEA0183Msg);
+                    }
+                }
+            }   
         }
+
     }
 
     //*****************************************************************************