diff --git a/lib/boatData/GwBoatData.cpp b/lib/boatData/GwBoatData.cpp
index cf217b5..2767dfc 100644
--- a/lib/boatData/GwBoatData.cpp
+++ b/lib/boatData/GwBoatData.cpp
@@ -1,54 +1,29 @@
 #include "GwBoatData.h"
 
-GwBoatItem *GwBoatData::find(String name,bool doCreate){
-    GwBoatItemMap::iterator it;
-    if ((it=values.find(name)) != values.end()){
-        return it->second;
-    }
-    if (! doCreate) return NULL;
-    GwBoatItem *ni=new GwBoatItem();
-    values[name]=ni;
-    return ni;
-}
 GwBoatData::GwBoatData(GwLog *logger){
     
 }
 GwBoatData::~GwBoatData(){
-    GwBoatItemMap::iterator it;
+    GwBoatItemBase::GwBoatItemMap::iterator it;
     for (it=values.begin() ; it != values.end();it++){
         delete it->second;
     }
 }
-void GwBoatData::update(String name,const char *value){
-   GwBoatItem *i=find(name);
-   i->update(value); 
-}
-void GwBoatData::update(String name, String value){
-   GwBoatItem *i=find(name);
-   i->update(value); 
-}
-void GwBoatData::update(String name, long value){
-   GwBoatItem *i=find(name);
-   i->update(value); 
-}
-void GwBoatData::update(String name, double value){
-   GwBoatItem *i=find(name);
-   i->update(value); 
-}
-void GwBoatData::update(String name, bool value){
-    GwBoatItem *i=find(name);
-    i->update(value); 
-}
+
 String GwBoatData::toJson() const {
-    long minTime=millis() - maxAge;
+    long minTime=millis();
     DynamicJsonDocument json(800);
-    GwBoatItemMap::const_iterator it;
+    GwBoatItemBase::GwBoatItemMap::const_iterator it;
     for (it=values.begin() ; it != values.end();it++){
         if (it->second->isValid(minTime)){
-            json[it->first]=it->second->getValue();
+            it->second->toJsonDoc(&json,it->first);
         }
     }
     String buf;
     serializeJson(json,buf);
     return buf;
+}
+
+GwBoatItemBase::GwBoatItemMap * GwBoatData::getValues(){
+    return &values;
 }
\ No newline at end of file
diff --git a/lib/boatData/GwBoatData.h b/lib/boatData/GwBoatData.h
index 27bc2bf..f00e2b1 100644
--- a/lib/boatData/GwBoatData.h
+++ b/lib/boatData/GwBoatData.h
@@ -6,62 +6,70 @@
 #include <Arduino.h>
 #include <map>
 #define GW_BOAT_VALUE_LEN 32
-class GwBoatItem{
-    private:
-        char value[GW_BOAT_VALUE_LEN];
+class GwBoatItemBase{
+    public:
+        static const long INVALID_TIME=60000;
+        typedef std::map<String,GwBoatItemBase*> GwBoatItemMap;
+    protected:
         long lastSet;
+        long invalidTime=INVALID_TIME;
         void uls(){
             lastSet=millis();
         }
     public:
-        const char * getValue() const{return value;}
         long getLastSet() const {return lastSet;}
-        bool isValid(long minTime) const {return lastSet > minTime;}
-        GwBoatItem(){
-            value[0]=0;
+        bool isValid(long now) const {
+            return (lastSet + invalidTime) >= now;
+        }
+        GwBoatItemBase(long invalidTime=INVALID_TIME){
             lastSet=-1;
+            this->invalidTime=invalidTime;
         }
-        void update(String nv){
-            strncpy(value,nv.c_str(),GW_BOAT_VALUE_LEN-1);
-            uls();
-        }
-        void update(const char * nv){
-            strncpy(value,nv,GW_BOAT_VALUE_LEN-1);
-        }
-        void update(long nv){
-            ltoa(nv,value,10);
-            uls();
-        }
-        void update(bool nv){
-            if (nv) strcpy_P(value,PSTR("true"));
-            else strcpy_P(value,PSTR("false"));
-            uls();
-        }
-        void update(double nv){
-            dtostrf(nv,3,7,value);
-            uls();
-        }
+        virtual ~GwBoatItemBase(){}
         void invalidate(){
             lastSet=0;
         }
-
+        virtual void toJsonDoc(DynamicJsonDocument *doc,String name)=0;
 };
 class GwBoatData{
-    typedef std::map<String,GwBoatItem*> GwBoatItemMap;
     private:
-        const long maxAge=60000; //max age for valid data in ms
         GwLog *logger;
-        GwBoatItemMap values;
-        GwBoatItem *find(String name, bool doCreate=true);
+        GwBoatItemBase::GwBoatItemMap values;
     public:
         GwBoatData(GwLog *logger);
-        ~GwBoatData();    
-        void update(String name,const char *value);
-        void update(String name, String value);
-        void update(String name, long value);
-        void update(String name, bool value);
-        void update(String name, double value);
+        ~GwBoatData();
+        GwBoatItemBase::GwBoatItemMap * getValues();    
         String toJson() const;
-
+    friend class GwBoatItemBase;    
 };
+template<class T> class GwBoatItem : public GwBoatItemBase{
+    private:
+        T data;
+    public:
+        GwBoatItem(long invalidTime=INVALID_TIME): GwBoatItemBase(invalidTime){}
+        virtual ~GwBoatItem(){}
+        void update(T nv){
+            data=nv;
+            uls();
+        }
+        T getData(){
+            return data;
+        }
+        virtual void toJsonDoc(DynamicJsonDocument *doc,String name){
+            (*doc)[name]=data;
+        }
+        static GwBoatItem<T> *findOrCreate(GwBoatData *handler, String name,bool doCreate=true, 
+            long invalidTime=GwBoatItemBase::INVALID_TIME){
+            GwBoatItemMap *values=handler->getValues();    
+            GwBoatItemMap::iterator it;
+            if ((it=values->find(name)) != values->end()){
+                return (GwBoatItem<T> *)it->second;
+            }
+            if (! doCreate) return NULL;
+            GwBoatItem<T> *ni=new GwBoatItem<T>(invalidTime);
+            (*values)[name]=ni;
+            return ni; 
+        }
+};
+
 #endif
\ No newline at end of file
diff --git a/lib/nmea2kto0183/N2kDataToNMEA0183.cpp b/lib/nmea2kto0183/N2kDataToNMEA0183.cpp
index 1b7629b..2b9b585 100644
--- a/lib/nmea2kto0183/N2kDataToNMEA0183.cpp
+++ b/lib/nmea2kto0183/N2kDataToNMEA0183.cpp
@@ -29,6 +29,30 @@
 
 const double radToDeg = 180.0 / M_PI;
 
+static void updateDouble(GwBoatItem<double> *item,double value){
+  if (value == N2kDoubleNA) return;
+  item->update(value);
+}
+
+N2kDataToNMEA0183::N2kDataToNMEA0183(GwLog * logger, GwBoatData *boatData, tNMEA2000 *NMEA2000, tNMEA0183 *NMEA0183) : tNMEA2000::tMsgHandler(0,NMEA2000){
+    SendNMEA0183MessageCallback=0;
+    pNMEA0183=NMEA0183;
+    Variation=N2kDoubleNA;  COG=N2kDoubleNA; SOG=N2kDoubleNA;
+    SecondsSinceMidnight=N2kDoubleNA; DaysSince1970=N2kUInt16NA;
+    LastPosSend=0;
+    lastLoopTime=0;
+    NextRMCSend=millis()+RMCPeriod;
+    LastHeadingTime=0;
+    LastCOGSOGTime=0;
+    LastWindTime=0;
+    this->logger=logger;
+    this->boatData=boatData;
+    heading=GwBoatItem<double>::findOrCreate(boatData,F("Heading"),true,2000);
+    latitude=GwBoatItem<double>::findOrCreate(boatData,F("Latitude"),true,4000);
+    longitude=GwBoatItem<double>::findOrCreate(boatData,F("Longitude"),true,4000);
+    altitude=GwBoatItem<double>::findOrCreate(boatData,F("Altitude"),true,4000);
+  }
+
 //*****************************************************************************
 void N2kDataToNMEA0183::HandleMsg(const tN2kMsg &N2kMsg) {
   switch (N2kMsg.PGN) {
@@ -52,15 +76,10 @@ void N2kDataToNMEA0183::loop() {
   if ( now < (lastLoopTime + 100)) return;
   lastLoopTime=now;
   SendRMC();
-  if ( (LastHeadingTime + 2000) < now ) Heading = N2kDoubleNA;
   if ( (LastCOGSOGTime + 2000) < now ) {
     COG = N2kDoubleNA;
     SOG = N2kDoubleNA;
   }
-  if ( (LastPositionTime + 4000) < now ) {
-    Latitude = N2kDoubleNA;
-    Longitude = N2kDoubleNA;
-  }
   if ( ( LastWindTime + 2000) < now ) {
     AWS = N2kDoubleNA;
     AWA = N2kDoubleNA;
@@ -68,7 +87,7 @@ void N2kDataToNMEA0183::loop() {
     TWA = N2kDoubleNA;
     TWD = N2kDoubleNA;    
   }
-
+  /*
   boatData->update(F("Latitude"),Latitude);
   boatData->update(F("Longitude"),Longitude);
   boatData->update(F("Altitude"),Altitude);
@@ -91,7 +110,7 @@ void N2kDataToNMEA0183::loop() {
   boatData->update(F("Variation"),Variation *radToDeg);
   boatData->update(F("GPSTime"),SecondsSinceMidnight);
   boatData->update(F("DaysSince1970"),(long)DaysSince1970);
-    
+  */  
 }
 
 //*****************************************************************************
@@ -107,13 +126,13 @@ void N2kDataToNMEA0183::HandleHeading(const tN2kMsg &N2kMsg) {
   double _Deviation = 0;
   double _Variation;
   tNMEA0183Msg NMEA0183Msg;
-
+  double Heading;
   if ( ParseN2kHeading(N2kMsg, SID, Heading, _Deviation, _Variation, ref) ) {
     if ( ref == N2khr_magnetic ) {
       if ( !N2kIsNA(_Variation) ) Variation = _Variation; // Update Variation
       if ( !N2kIsNA(Heading) && !N2kIsNA(Variation) ) Heading -= Variation;
     }
-    LastHeadingTime = millis();
+    updateDouble(heading,Heading);
     if ( NMEA0183SetHDG(NMEA0183Msg, Heading, _Deviation, Variation) ) {
       SendMessage(NMEA0183Msg);
     }
@@ -139,8 +158,8 @@ void N2kDataToNMEA0183::HandleBoatSpeed(const tN2kMsg &N2kMsg) {
   if ( ParseN2kBoatSpeed(N2kMsg, SID, WaterReferenced, GroundReferenced, SWRT) ) {
     tNMEA0183Msg NMEA0183Msg;
     STW=WaterReferenced;
-    double MagneticHeading = ( !N2kIsNA(Heading) && !N2kIsNA(Variation) ? Heading + Variation : NMEA0183DoubleNA);
-    if ( NMEA0183SetVHW(NMEA0183Msg, Heading, MagneticHeading, WaterReferenced) ) {
+    double MagneticHeading = ( heading->isValid(millis()) && !N2kIsNA(Variation) ? heading->getData() + Variation : NMEA0183DoubleNA);
+    if ( NMEA0183SetVHW(NMEA0183Msg, heading->getData(), MagneticHeading, WaterReferenced) ) {
       SendMessage(NMEA0183Msg);
     }
   }
@@ -169,9 +188,11 @@ void N2kDataToNMEA0183::HandleDepth(const tN2kMsg &N2kMsg) {
 
 //*****************************************************************************
 void N2kDataToNMEA0183::HandlePosition(const tN2kMsg &N2kMsg) {
-
+  double Latitude;
+  double Longitude;
   if ( ParseN2kPGN129025(N2kMsg, Latitude, Longitude) ) {
-    LastPositionTime = millis();
+    updateDouble(latitude,Latitude);
+    updateDouble(longitude,Longitude);
   }
 }
 
@@ -207,11 +228,15 @@ void N2kDataToNMEA0183::HandleGNSS(const tN2kMsg &N2kMsg) {
   tN2kGNSStype ReferenceStationType;
   uint16_t ReferenceSationID;
   double AgeOfCorrection;
-
+  double Latitude;
+  double Longitude;
+  double Altitude;
   if ( ParseN2kGNSS(N2kMsg, SID, DaysSince1970, SecondsSinceMidnight, Latitude, Longitude, Altitude, GNSStype, GNSSmethod,
                     nSatellites, HDOP, PDOP, GeoidalSeparation,
                     nReferenceStations, ReferenceStationType, ReferenceSationID, AgeOfCorrection) ) {
-    LastPositionTime = millis();
+    updateDouble(latitude,Latitude);                  
+    updateDouble(longitude,Longitude);
+    updateDouble(altitude,Altitude);
   }
 }
 
@@ -241,7 +266,7 @@ void N2kDataToNMEA0183::HandleWind(const tN2kMsg &N2kMsg) {
 
     if (WindReference == N2kWind_Apparent && SOG != N2kDoubleNA) { // Lets calculate and send TWS/TWA if SOG is available
       
-      AWD=WindAngle*radToDeg + Heading*radToDeg;
+      AWD=WindAngle*radToDeg + heading->getData()*radToDeg;
       if (AWD>360) AWD=AWD-360;
       if (AWD<0) AWD=AWD+360;
 
@@ -280,9 +305,10 @@ void N2kDataToNMEA0183::HandleWind(const tN2kMsg &N2kMsg) {
 }
   //*****************************************************************************
   void N2kDataToNMEA0183::SendRMC() {
-    if ( NextRMCSend <= millis() && !N2kIsNA(Latitude) ) {
+    long now=millis();
+    if ( NextRMCSend <= millis() && latitude->isValid(now) ) {
       tNMEA0183Msg NMEA0183Msg;
-      if ( NMEA0183SetRMC(NMEA0183Msg, SecondsSinceMidnight, Latitude, Longitude, COG, SOG, DaysSince1970, Variation) ) {
+      if ( NMEA0183SetRMC(NMEA0183Msg, SecondsSinceMidnight, latitude->getData(), longitude->getData(), COG, SOG, DaysSince1970, Variation) ) {
         SendMessage(NMEA0183Msg);
       }
       SetNextRMCSend();
diff --git a/lib/nmea2kto0183/N2kDataToNMEA0183.h b/lib/nmea2kto0183/N2kDataToNMEA0183.h
index 9b8aed6..45cbad9 100644
--- a/lib/nmea2kto0183/N2kDataToNMEA0183.h
+++ b/lib/nmea2kto0183/N2kDataToNMEA0183.h
@@ -36,11 +36,11 @@ public:
     
 protected:
   static const unsigned long RMCPeriod=500;
-  double Latitude;
-  double Longitude;
-  double Altitude;
+  GwBoatItem<double> *latitude;
+  GwBoatItem<double> *longitude;
+  GwBoatItem<double> * altitude;
   double Variation;
-  double Heading;
+  GwBoatItem<double> *heading;
   double COG;
   double SOG;
   double STW;
@@ -68,7 +68,6 @@ protected:
     
   unsigned long LastHeadingTime;
   unsigned long LastCOGSOGTime;
-  unsigned long LastPositionTime;
   unsigned long LastPosSend;
   unsigned long LastWindTime;
   unsigned long NextRMCSend;
@@ -99,22 +98,7 @@ protected:
   void SendMessage(const tNMEA0183Msg &NMEA0183Msg);
 
 public:
-  N2kDataToNMEA0183(GwLog * logger, GwBoatData *boatData, tNMEA2000 *NMEA2000, tNMEA0183 *NMEA0183) : tNMEA2000::tMsgHandler(0,NMEA2000) {
-    SendNMEA0183MessageCallback=0;
-    pNMEA0183=NMEA0183;
-    Latitude=N2kDoubleNA; Longitude=N2kDoubleNA; Altitude=N2kDoubleNA;
-    Variation=N2kDoubleNA; Heading=N2kDoubleNA; COG=N2kDoubleNA; SOG=N2kDoubleNA;
-    SecondsSinceMidnight=N2kDoubleNA; DaysSince1970=N2kUInt16NA;
-    LastPosSend=0;
-    lastLoopTime=0;
-    NextRMCSend=millis()+RMCPeriod;
-    LastHeadingTime=0;
-    LastCOGSOGTime=0;
-    LastPositionTime=0;
-    LastWindTime=0;
-    this->logger=logger;
-    this->boatData=boatData;
-  }
+  N2kDataToNMEA0183(GwLog * logger, GwBoatData *boatData, tNMEA2000 *NMEA2000, tNMEA0183 *NMEA0183) ;
   void HandleMsg(const tN2kMsg &N2kMsg);
   void SetSendNMEA0183MessageCallback(tSendNMEA0183MessageCallback _SendNMEA0183MessageCallback) {
     SendNMEA0183MessageCallback=_SendNMEA0183MessageCallback;