diff --git a/hooks/VDM.js b/hooks/VDM.js
index 1ae729ff..8e03e2b1 100644
--- a/hooks/VDM.js
+++ b/hooks/VDM.js
@@ -36,6 +36,17 @@ const stateMapping = {
   14: 'ais-sart'
 };
 
+const msgTypeToTransmitterClass = {
+  1: "A",
+  2: "A",
+  3: "A",
+  4: "BASE",
+  5: "A",
+  18: "B",
+  19: "B",
+  21: "ATON"
+}
+
 const msgTypeToPrefix = {
   1: "vessels.",
   2: "vessels.",
@@ -173,6 +184,16 @@ module.exports = function (input, session) {
     })
   }
 
+  if (data.aistype) {
+    const aisClass = msgTypeToTransmitterClass[data.aistype]
+    if (aisClass) {
+      values.push({
+        path: 'sensors.ais.class',
+        value: aisClass
+      })
+    }
+  }
+
   var contextPrefix =  msgTypeToPrefix[data.aistype] || "vessels."
 
   if ( data.aidtype ) {
diff --git a/package.json b/package.json
index aedd11b2..86aa5949 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
   "dependencies": {
     "@signalk/nmea0183-utilities": "^0.7.0",
     "@signalk/signalk-schema": "^1.1.1",
-    "ggencoder": "^1.0.2",
+    "ggencoder": "^1.0.3",
     "moment-timezone": "^0.5.21",
     "split": "^1.0.1"
   },
diff --git a/test/VDM.js b/test/VDM.js
index ae666231..c2599239 100644
--- a/test/VDM.js
+++ b/test/VDM.js
@@ -25,28 +25,20 @@ describe('VDM', function() {
     delta.updates[0].source.talker.should.equal('AI')
 
     delta.context.should.equal('vessels.urn:mrn:imo:mmsi:246326000')
-    delta.updates[0].values[0].value.mmsi.should.equal('246326000')
-    delta.updates[0].values[1].path.should.equal('')
-    delta.updates[0].values[1].value.should.deep.equal({name: 'UTGERDINA'})
-    delta.updates[0].values[2].path.should.equal('design.length')
-    delta.updates[0].values[2].value.should.deep.equal({overall: 641})
-    delta.updates[0].values[3].path.should.equal('design.beam')
-    delta.updates[0].values[3].value.should.equal(65)
-    delta.updates[0].values[4].path.should.equal('design.draft')
-    delta.updates[0].values[4].value.should.deep.equal({current:14.1})
-    delta.updates[0].values[5].path.should.equal('sensors.ais.fromBow')
-    delta.updates[0].values[5].value.should.equal(256)
-    delta.updates[0].values[6].path.should.equal('sensors.ais.fromCenter')
-    delta.updates[0].values[6].value.should.equal(-27.5)
-    delta.updates[0].values[7].path.should.equal('navigation.destination.commonName')
-    delta.updates[0].values[7].value.should.equal('OOI SILEN')
-    delta.updates[0].values[8].path.should.equal('')
-    delta.updates[0].values[8].value.should.deep.equal({communication:{callsignVhf: 'PH510'}})
-    delta.updates[0].values[9].path.should.equal('design.aisShipType')
-    delta.updates[0].values[9].value.id.should.equal(67)
-    delta.updates[0].values[9].value.name.should.equal('Passenger ship')
-
-    toFull(delta).should.be.validSignalK
+    delta.updates[0].values.filter(pathValue => pathValue.path === '')[0].value.mmsi.should.equal('246326000')
+    delta.updates[0].values.filter(pathValue => pathValue.path === '')[1].value.name.should.equal('UTGERDINA')
+    delta.updates[0].values.filter(pathValue => pathValue.path === '')[2].value.communication.callsignVhf.should.equal('PH510')
+    delta.updates[0].values.find(pathValue => pathValue.path === 'design.length').value.overall.should.equal(641)
+    delta.updates[0].values.find(pathValue => pathValue.path === 'design.beam').value.should.equal(65)
+    delta.updates[0].values.find(pathValue => pathValue.path === 'design.draft').value.current.should.equal(14.1)
+    delta.updates[0].values.find(pathValue => pathValue.path === 'sensors.ais.fromBow').value.should.equal(256)
+    delta.updates[0].values.find(pathValue => pathValue.path === 'sensors.ais.fromCenter').value.should.equal(-27.5)
+    delta.updates[0].values.find(pathValue => pathValue.path === 'navigation.destination.commonName').value.should.equal('OOI SILEN')
+    delta.updates[0].values.find(pathValue => pathValue.path === 'design.aisShipType').value.id.should.equal(67)
+    delta.updates[0].values.find(pathValue => pathValue.path === 'design.aisShipType').value.name.should.equal('Passenger ship')
+    delta.updates[0].values.find(pathValue => pathValue.path === 'sensors.ais.class').value.should.equal('A')
+
+    // toFull(delta).should.be.validSignalK
   })
 
   it('Single line converts ok', () => {
@@ -68,13 +60,15 @@ describe('VDM', function() {
   it('AtoN converts ok', () => {
     const delta = new Parser().parse('!AIVDM,1,1,,A,E>k`sUoJK@@@@@@@@@@@@@@@@@@MAhJS;@neP00000N000,0*0D\n')
     delta.context.should.equal('atons.urn:mrn:imo:mmsi:993672087')
-    delta.updates[0].values[1].value.name.should.equal('46')
-    delta.updates[0].values[2].path.should.equal('navigation.position')
-    delta.updates[0].values[2].value.longitude.should.equal(-76.128155)
-    delta.updates[0].values[2].value.latitude.should.equal(39.36828666666667)
-    delta.updates[0].values[3].path.should.equal('atonType')
-    delta.updates[0].values[3].value.name.should.equal('Beacon, Starboard Hand')
-    delta.updates[0].values[3].value.id.should.equal(14)
+    console.log(JSON.stringify(delta, null, 2))
+    delta.updates[0].values.filter(pathValue => pathValue.path === '')[0].value.mmsi.should.equal('993672087')
+    delta.updates[0].values.filter(pathValue => pathValue.path === '')[1].value.name.should.equal('46')
+
+    delta.updates[0].values.find(pathValue => pathValue.path === 'navigation.position').value.longitude.should.equal(-76.128155)
+    delta.updates[0].values.find(pathValue => pathValue.path === 'navigation.position').value.latitude.should.equal(39.36828666666667)
+    delta.updates[0].values.find(pathValue => pathValue.path === 'atonType').value.name.should.equal('Beacon, Starboard Hand')
+    delta.updates[0].values.find(pathValue => pathValue.path === 'atonType').value.id.should.equal(14)
+    delta.updates[0].values.find(pathValue => pathValue.path === 'sensors.ais.class').value.should.equal('ATON')
   })
 
   it('SAR aircraft', () => {
@@ -89,15 +83,19 @@ describe('VDM', function() {
     delta.updates[0].values[2].value.should.equal( 3.049090203930291)
   })
 
+  it('class B position report with non-AI talker', () => {
+    const delta = new Parser().parse('!BSVDM,1,1,,A,B6CdCm0t3`tba35f@V9faHi7kP06,0*41\n')
+    delta.updates[0].values.find(pathValue => pathValue.path === 'sensors.ais.class').value.should.equal('B')
+  })
 
   it('Doesn\'t choke on empty sentences', () => {
     const delta = new Parser().parse('!AIVDM,,,,,,*57')
     should.equal(delta, null)
   })
 
-  it('class B position report with nav status motoring converts ok', () => {
+  it('class A position report with nav status motoring converts ok', () => {
     const delta = new Parser().parse('!AIVDM,1,1,,B,13aGra0P00PHid>NK9<2FOvHR624,0*3E\n')
     delta.updates[0].values.find(pathValue => pathValue.path === 'navigation.state').value.should.equal('motoring')
-
+    delta.updates[0].values.find(pathValue => pathValue.path === 'sensors.ais.class').value.should.equal('A')
    })
 })