diff --git a/schemas/groups/navigation.json b/schemas/groups/navigation.json
index 9e4d6200..73bc1d00 100644
--- a/schemas/groups/navigation.json
+++ b/schemas/groups/navigation.json
@@ -1,7 +1,7 @@
 {
   "type": "object",
   "$schema": "http://json-schema.org/draft-04/schema#",
-  "id": "https://signalk.org/specification/1.5.1/schemas/groups/navigation.json#",
+  "id": "https://signalk.org/specification/1.5.2/schemas/groups/navigation.json#",
   "description": "Schema describing the navigation child-object of a Vessel.",
   "title": "navigation",
   "definitions": {
@@ -719,6 +719,21 @@
         "position": {
           "description": "The actual anchor position of the vessel in 3 dimensions, probably an estimate at best",
           "$ref": "../definitions.json#/definitions/position"
+        },
+        "lineLength": {
+          "description": "The lenght of the anchor line",
+          "$ref": "../definitions.json#/definitions/numberValue",
+          "units": "m"
+        },
+        "motorTemperature": {
+          "description": "The temperature of the motor anchor",
+          "$ref": "../definitions.json#/definitions/numberValue",
+          "units": "k"
+        },
+        "motorCurrent": {
+          "description": "The current in amperes that the motor takes",
+          "$ref": "../definitions.json#/definitions/numberValue",
+          "units": "A"
         }
       }
     },