diff --git a/lib/aisparser/ais_decoder.cpp b/lib/aisparser/ais_decoder.cpp
index 558c12a..6fece95 100644
--- a/lib/aisparser/ais_decoder.cpp
+++ b/lib/aisparser/ais_decoder.cpp
@@ -842,11 +842,18 @@ bool AisDecoder::checkTalkerId(const StringRef &_strTalkerId)
   Decode next sentence (starts reading from input buffer with the specified offset; returns the number of bytes processed, or 0 when no more messages can be decoded).
   Has to be called until it returns 0, to ensure that any buffered multi-line strings are backed up properly.
 */
-size_t AisDecoder::decodeMsg(const char *_pNmeaBuffer, size_t _uBufferSize, size_t _uOffset, const SentenceParser &_parser)
+size_t AisDecoder::decodeMsg(const char *_pNmeaBuffer, size_t _uBufferSize, size_t _uOffset, 
+  const SentenceParser &_parser, bool treatAsComplete)
 {
   // process and decode AIS strings
   StringRef strLine;
-  size_t n = getLine(strLine, _pNmeaBuffer, _uBufferSize, _uOffset);
+  size_t n = 0;
+  if (treatAsComplete){
+    strLine=StringRef(_pNmeaBuffer+_uOffset,_uBufferSize);
+  } 
+  else{
+    n=getLine(strLine, _pNmeaBuffer, _uBufferSize, _uOffset);
+  }
   if (strLine.size() > 2)      // ignore empty lines
   {
     // clear user data
diff --git a/lib/aisparser/ais_decoder.h b/lib/aisparser/ais_decoder.h
index 9537a1e..c908839 100644
--- a/lib/aisparser/ais_decoder.h
+++ b/lib/aisparser/ais_decoder.h
@@ -234,7 +234,8 @@ namespace AIS
             Decode next sentence (starts reading from input buffer with the specified offset; returns the number of bytes processed, or 0 when no more messages can be decoded).
             Has to be called until it returns 0, to ensure that any buffered multi-line strings are backed up properly.
          */
-        size_t decodeMsg(const char *_pNmeaBuffer, size_t _uBufferSize, size_t _uOffset, const SentenceParser &_parser);
+        size_t decodeMsg(const char *_pNmeaBuffer, size_t _uBufferSize, size_t _uOffset, 
+            const SentenceParser &_parser, bool treatAsComplete=false);
         
         /// returns the total number of messages processed
         uint64_t getTotalMessageCount() const {return m_uTotalMessages;}
diff --git a/lib/nmea0183ton2k/NMEA0183AIStoNMEA2000.h b/lib/nmea0183ton2k/NMEA0183AIStoNMEA2000.h
index 0593bee..4c4b440 100644
--- a/lib/nmea0183ton2k/NMEA0183AIStoNMEA2000.h
+++ b/lib/nmea0183ton2k/NMEA0183AIStoNMEA2000.h
@@ -18,6 +18,7 @@
 #include "default_sentence_parser.h"
 #include "NMEA0183DataToN2K.h"
 #include "NMEA0183.h"
+#include "GwLog.h"
 
 const double pi = 3.1415926535897932384626433832795;
 const double knToms = 1852.0 / 3600.0;
@@ -30,17 +31,46 @@ class MyAisDecoder : public AIS::AisDecoder
 {
   private:
     NMEA0183DataToN2K::N2kSender sender;
+    GwLog *logger;
     void send(const tN2kMsg &msg){
       (*sender)(msg);
     }
     AIS::DefaultSentenceParser parser;
   public:
-    MyAisDecoder(NMEA0183DataToN2K::N2kSender sender)
+    MyAisDecoder(GwLog *logger,NMEA0183DataToN2K::N2kSender sender)
     {
+      this->logger=logger;
       this->sender=sender;
     }
 
   protected:
+    double decodeRot(int iRot){
+      //see https://gpsd.gitlab.io/gpsd/AIVDM.html#_type_5_static_and_voyage_related_data
+      //and https://opencpn.org/wiki/dokuwiki/doku.php?id=opencpn:supplementary_software:nmea2000
+      double rot=N2kDoubleNA;
+      if (iRot == 127) rot=10;
+      else if (iRot == -127) rot=-10;
+      else if (iRot == 0) rot=0;
+      else if ( 1<= iRot && iRot <= 126 ) rot= iRot *iRot / 22.401289;
+      else if ( iRot >= -126 && iRot <= -1) rot= iRot * iRot / -22.401289 ;
+      //rot now in deg/minute
+      rot=rot* degToRad / 60.0; //N"K expects rot in radian/s
+      return rot;
+    }
+    double decodeCog(int iCog){
+      double cog = N2kDoubleNA;
+      if (iCog >= 0 && iCog < 3600){
+        cog= iCog/10.0 * degToRad; 
+      }
+      return cog;
+    }
+    double decodeHeading(int iHeading){
+      double heading=N2kDoubleNA;
+      if ( iHeading >=0 && iHeading <=359){
+        heading=iHeading *degToRad;
+      }
+      return heading;
+    }
     virtual void onType123(unsigned int _uMsgType, unsigned int _uMmsi, unsigned int _uNavstatus,
                            int _iRot, unsigned int _uSog, bool _bPosAccuracy,
                            long _iPosLon, long _iPosLat, int _iCog, int _iHeading, int _Repeat, bool _Raim,
@@ -54,8 +84,8 @@ class MyAisDecoder : public AIS::AisDecoder
       SetN2kAISClassAPosition(N2kMsg, _uMsgType, (tN2kAISRepeat)_Repeat, _uMmsi,
                               _iPosLat / 600000.0, _iPosLon / 600000.0,
                               _bPosAccuracy, _Raim, _timestamp,
-                              _iCog * degToRad, _uSog * knToms / 10.0,
-                              _iHeading * degToRad, _iRot, (tN2kAISNavStatus)_uNavstatus);
+                              decodeCog(_iCog) , _uSog * knToms / 10.0,
+                              decodeHeading(_iHeading), decodeRot(_iRot), (tN2kAISNavStatus)_uNavstatus);
 
       send(N2kMsg);
     }
@@ -96,9 +126,12 @@ class MyAisDecoder : public AIS::AisDecoder
       char Name[30];
       char Dest[30];
 
-      strncpy(CS, _strCallsign.c_str(), sizeof(CS));
-      strncpy(Name, _strName.c_str(), sizeof(Name));
-      strncpy(Dest, _strDestination.c_str(), sizeof(Dest));
+      strncpy(CS, _strCallsign.c_str(), sizeof(CS)-1);
+      CS[29]=0;
+      strncpy(Name, _strName.c_str(), sizeof(Name)-1);
+      Name[29]=0;
+      strncpy(Dest, _strDestination.c_str(), sizeof(Dest)-1);
+      Dest[29]=0;
 
       // PGN129794
       SetN2kAISClassAStatic(N2kMsg, _uMsgType, (tN2kAISRepeat) _repeat, _uMmsi,
@@ -120,7 +153,8 @@ class MyAisDecoder : public AIS::AisDecoder
 
       tN2kMsg N2kMsg;
       char Text[162];
-      strncpy(Text, _strText.c_str(), sizeof(Text));
+      strncpy(Text, _strText.c_str(), sizeof(Text)-1);
+      Text[161]=0;
 
       N2kMsg.SetPGN(129802UL);
       N2kMsg.Priority = 4;
@@ -151,8 +185,8 @@ class MyAisDecoder : public AIS::AisDecoder
       // PGN129039
       SetN2kAISClassBPosition(N2kMsg, _uMsgType, (tN2kAISRepeat) _repeat, _uMmsi,
                               _iPosLat / 600000.0, _iPosLon / 600000.0, _bPosAccuracy, _raim,
-                              _timestamp, _iCog * degToRad, _uSog * knToms / 10.0,
-                              _iHeading * degToRad, (tN2kAISUnit) _unit,
+                              _timestamp, decodeCog(_iCog), _uSog * knToms / 10.0,
+                              decodeHeading(_iHeading), (tN2kAISUnit) _unit,
                               _diplay, _dsc, _band, _msg22, (tN2kAISMode) _assigned, _state);
 
       send(N2kMsg);
@@ -170,7 +204,8 @@ class MyAisDecoder : public AIS::AisDecoder
       // PGN129040
 
       char Name[21] = "";
-      strncpy(Name, _strName.c_str(), sizeof(Name));
+      strncpy(Name, _strName.c_str(), sizeof(Name)-1);
+      Name[20]=0;
 
       N2kMsg.SetPGN(129040UL);
       N2kMsg.Priority = 4;
@@ -179,12 +214,12 @@ class MyAisDecoder : public AIS::AisDecoder
       N2kMsg.Add4ByteDouble(_iPosLon / 600000.0, 1e-07);
       N2kMsg.Add4ByteDouble(_iPosLat / 600000.0, 1e-07);
       N2kMsg.AddByte((_timestamp & 0x3f) << 2 | (_raim & 0x01) << 1 | (_bPosAccuracy & 0x01));
-      N2kMsg.Add2ByteUDouble(_iCog * degToRad, 1e-04);
+      N2kMsg.Add2ByteUDouble(decodeCog(_iCog), 1e-04);
       N2kMsg.Add2ByteUDouble(_uSog * knToms / 10.0, 0.01);
       N2kMsg.AddByte(0xff); // Regional Application
       N2kMsg.AddByte(0xff); // Regional Application
       N2kMsg.AddByte(_uType );
-      N2kMsg.Add2ByteUDouble(_iHeading * degToRad, 1e-04);
+      N2kMsg.Add2ByteUDouble(decodeHeading(_iHeading), 1e-04);
       N2kMsg.AddByte(_fixtype << 4);
       N2kMsg.Add2ByteDouble(_uToBow + _uToStern, 0.1);
       N2kMsg.Add2ByteDouble(_uToPort + _uToStarboard, 0.1);
@@ -208,7 +243,8 @@ class MyAisDecoder : public AIS::AisDecoder
 
       tN2kMsg N2kMsg;
       char Name[30];
-      strncpy(Name, _strName.c_str(), sizeof(Name));
+      strncpy(Name, _strName.c_str(), sizeof(Name)-1);
+      Name[29]=0;
 
       // PGN129809
       SetN2kAISClassBStaticPartA(N2kMsg, _uMsgType, (tN2kAISRepeat) _repeat, _uMmsi, Name);
@@ -228,8 +264,10 @@ class MyAisDecoder : public AIS::AisDecoder
       char CS[30];
       char Vendor[30];
 
-      strncpy(CS, _strCallsign.c_str(), sizeof(CS));
-      strncpy(Vendor, _strVendor.c_str(), sizeof(Vendor));
+      strncpy(CS, _strCallsign.c_str(), sizeof(CS)-1);
+      CS[29]=0;
+      strncpy(Vendor, _strVendor.c_str(), sizeof(Vendor)-1);
+      Vendor[29]=0;
 
       // PGN129810
       SetN2kAISClassBStaticPartB(N2kMsg, _uMsgType, (tN2kAISRepeat)_repeat, _uMmsi,
@@ -255,24 +293,17 @@ class MyAisDecoder : public AIS::AisDecoder
       std::string msg(_strMessage.data(), _strMessage.size());
       AIS::stripTrailingWhitespace(msg);
 
-      Serial.printf("%s [%s]\n", _strError.c_str(), msg.c_str());
+      LOG_DEBUG(GwLog::ERROR,"%s [%s]\n", _strError.c_str(), msg.c_str());
     }
 
     virtual void onParseError(const AIS::StringRef &_strMessage, const std::string &_strError) override {
       std::string msg(_strMessage.data(), _strMessage.size());
       AIS::stripTrailingWhitespace(msg);
 
-      Serial.printf("%s [%s]\n", _strError.c_str(), msg.c_str());
+      LOG_DEBUG(GwLog::ERROR,"%s [%s]\n", _strError.c_str(), msg.c_str());
     }
   public:
     void handleMessage(const char * msg){
-      int len=strlen(msg);
-      char buffer[len+1];
-      memcpy(buffer,msg,len);
-      strcat(buffer,"\n");
-      size_t i=0;
-      do {
-            i=decodeMsg(buffer,len+1,i,parser);
-      } while (i != 0) ;
+      size_t i=decodeMsg(msg,strlen(msg),0,parser,true);
     }
 };
diff --git a/lib/nmea0183ton2k/NMEA0183DataToN2K.cpp b/lib/nmea0183ton2k/NMEA0183DataToN2K.cpp
index 8135ccf..b15ba02 100644
--- a/lib/nmea0183ton2k/NMEA0183DataToN2K.cpp
+++ b/lib/nmea0183ton2k/NMEA0183DataToN2K.cpp
@@ -38,6 +38,7 @@ class SNMEA0183Msg : public tNMEA0183Msg{
                 if (!isAis) return MessageCode();
                 char buf[6];
                 strncpy(buf,line+1,5);
+                buf[5]=0;
                 return String(buf);
             }
 
@@ -233,7 +234,7 @@ private:
         converters.registerConverter(
             126992UL,129025UL,129026UL,127258UL, 
             String(F("RMC")),  &NMEA0183DataToN2KFunctions::convertRMC);
-        unsigned long aispgns[7]{129810UL,129809UL,129040UL,129039UL,129802UL,129794UL,129038UL};
+        unsigned long *aispgns=new unsigned long[7]{129810UL,129809UL,129040UL,129039UL,129802UL,129794UL,129038UL};
         converters.registerConverter(7,&aispgns[0],
             String(F("AIVDM")),&NMEA0183DataToN2KFunctions::convertAIVDX);
         converters.registerConverter(7,&aispgns[0],
@@ -256,7 +257,7 @@ public:
         bool rt = converters.handleMessage(code, msg, this);
         if (!rt)
         {
-            LOG_DEBUG(GwLog::DEBUG, "NMEA0183DataToN2K[%d] no handler for %s", sourceId, buffer);
+            LOG_DEBUG(GwLog::DEBUG, "NMEA0183DataToN2K[%d] no handler for (%s) %s", sourceId, code.c_str(), buffer);
         }
         else{
             LOG_DEBUG(GwLog::DEBUG+1, "NMEA0183DataToN2K[%d] handler done ", sourceId);
@@ -276,7 +277,7 @@ public:
     NMEA0183DataToN2KFunctions(GwLog *logger, GwBoatData *boatData, N2kSender callback)
         : NMEA0183DataToN2K(logger, boatData, callback)
     {
-        aisDecoder= new MyAisDecoder(this->sender);
+        aisDecoder= new MyAisDecoder(logger,this->sender);
         registerConverters();
         LOG_DEBUG(GwLog::LOG, "NMEA0183DataToN2KFunctions: registered %d converters", converters.numConverters());
     }
diff --git a/src/main.cpp b/src/main.cpp
index 136f051..d40c638 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -14,8 +14,8 @@
 
 #define VERSION "0.3.1"
 
-//#define GW_MESSAGE_DEBUG_ENABLED
-//#define FALLBACK_SERIAL
+// #define GW_MESSAGE_DEBUG_ENABLED
+// #define FALLBACK_SERIAL
 const unsigned long HEAP_REPORT_TIME=2000; //set to 0 to disable heap reporting
 #include "GwHardware.h"