diff --git a/ontology/saref4mari.ttl b/ontology/saref4mari.ttl
index e9afe3a3ddbf52e68dc5c0116bd3776aa117922b..da1b3835120d2db34519145a06b6983d3024873e 100644
--- a/ontology/saref4mari.ttl
+++ b/ontology/saref4mari.ttl
@@ -961,7 +961,10 @@ s4mari:Heading rdf:type owl:Class ;
                                  owl:onProperty saref:hasValue ;
                                  owl:qualifiedCardinality "1"^^xsd:nonNegativeInteger ;
                                  owl:onDataRange xsd:double
-                               ] .
+                               ] ;
+               rdfs:comment "The heading orientation of an object."@en ;
+               rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/Heading" ;
+               rdfs:label "Heading"@en .
 
 
 ###  https://saref.etsi.org/saref4mari/Incident
@@ -1127,7 +1130,10 @@ s4mari:Pitch rdf:type owl:Class ;
                                owl:onProperty saref:hasValue ;
                                owl:qualifiedCardinality "1"^^xsd:nonNegativeInteger ;
                                owl:onDataRange xsd:double
-                             ] .
+                             ] ;
+             rdfs:comment "The pitch orientation of an object."@en ;
+             rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/Pitch" ;
+             rdfs:label "Pitch"@en .
 
 
 ###  https://saref.etsi.org/saref4mari/PortFacilityLocation
@@ -1177,7 +1183,10 @@ s4mari:Roll rdf:type owl:Class ;
                               owl:onProperty saref:hasValue ;
                               owl:qualifiedCardinality "1"^^xsd:nonNegativeInteger ;
                               owl:onDataRange xsd:double
-                            ] .
+                            ] ;
+            rdfs:comment "The roll orientation of an object."@en ;
+            rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/Roll" ;
+            rdfs:label "Roll"@en .
 
 
 ###  https://saref.etsi.org/saref4mari/SensorState
@@ -1197,7 +1206,10 @@ s4mari:TideLevel rdf:type owl:Class ;
                                    owl:onProperty saref:hasValue ;
                                    owl:qualifiedCardinality "1"^^xsd:nonNegativeInteger ;
                                    owl:onDataRange xsd:double
-                                 ] .
+                                 ] ;
+                 rdfs:comment "The level of tide."@en ;
+                 rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/TideLevel" ;
+                 rdfs:label "TideLevel"@en .
 
 
 ###  https://saref.etsi.org/saref4mari/TidePressure
@@ -1216,7 +1228,10 @@ s4mari:TidePressure rdf:type owl:Class ;
                                                                                ]
                                                                              )
                                                       ]
-                                    ] .
+                                    ] ;
+                    rdfs:comment "The pressure caused by the tide."@en ;
+                    rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/TidePressure" ;
+                    rdfs:label "TidePressure"@en .
 
 
 ###  https://saref.etsi.org/saref4mari/UnderwaterPressure
@@ -1235,7 +1250,10 @@ s4mari:UnderwaterPressure rdf:type owl:Class ;
                                                                                      ]
                                                                                    )
                                                             ]
-                                          ] .
+                                          ] ;
+                          rdfs:comment "Pressure under the water."@en ;
+                          rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/UnderwaterPressure" ;
+                          rdfs:label "UnderwaterPressure"@en .
 
 
 ###  https://saref.etsi.org/saref4mari/UnderwaterSoundVelocity
@@ -1254,7 +1272,10 @@ s4mari:UnderwaterSoundVelocity rdf:type owl:Class ;
                                                                                           ]
                                                                                         )
                                                                  ]
-                                               ] .
+                                               ] ;
+                               rdfs:comment "The velocity of underwater sound."@en ;
+                               rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/UnderwaterSoundVelocity" ;
+                               rdfs:label "UnderwaterSoundVelocity"@en .
 
 
 ###  https://saref.etsi.org/saref4mari/UniqueIdentifier
@@ -1332,7 +1353,10 @@ s4mari:WaterConductance rdf:type owl:Class ;
                                                                                    ]
                                                                                  )
                                                           ]
-                                        ] .
+                                        ] ;
+                        rdfs:comment "The conductance of water."@en ;
+                        rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/WaterConductance" ;
+                        rdfs:label "WaterConductance"@en .
 
 
 ###  https://saref.etsi.org/saref4mari/WaterConductivity
@@ -1351,7 +1375,10 @@ s4mari:WaterConductivity rdf:type owl:Class ;
                                                                                     ]
                                                                                   )
                                                            ]
-                                         ] .
+                                         ] ;
+                         rdfs:comment "The conductivity of water."@en ;
+                         rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/WaterConductivity" ;
+                         rdfs:label "WaterConductivity"@en .
 
 
 ###  https://saref.etsi.org/saref4mari/WaterTemperature
@@ -1376,7 +1403,10 @@ s4mari:WaterTemperature rdf:type owl:Class ;
                                           owl:onProperty saref:hasValue ;
                                           owl:qualifiedCardinality "1"^^xsd:nonNegativeInteger ;
                                           owl:onDataRange xsd:double
-                                        ] .
+                                        ] ;
+                        rdfs:comment "The temperature of water."@en ;
+                        rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/WaterTemperature" ;
+                        rdfs:label "WaterTemperature"@en .
 
 
 ###  https://saref.etsi.org/saref4mari/WaterTurbidity
@@ -1395,7 +1425,10 @@ s4mari:WaterTurbidity rdf:type owl:Class ;
                                                                                  ]
                                                                                )
                                                         ]
-                                      ] .
+                                      ] ;
+                      rdfs:comment "The turbidity of water."@en ;
+                      rdfs:isDefinedBy "https://saref.etsi.org/saref4mari/WaterTurbidity" ;
+                      rdfs:label "WaterTurbidity"@en .
 
 
 ###  https://www.w3.org/ns/org#Organization