diff --git a/docs/ApiValidationRules.md b/docs/ApiValidationRules.md
index c769c31..9cf2073 100644
--- a/docs/ApiValidationRules.md
+++ b/docs/ApiValidationRules.md
@@ -97,6 +97,13 @@ If a validation rule fails the call should return 400 (Bad request) including an
     | evaluation | may not be set |
     | evaluation_message |  may not be set |
 
+#### Required fields
+* eta / etd (depending on value of type: 1: eta, 2: etd, 3: both)
+* type
+* ship_id
+* arrival_berth_id / departure_berth_id (depending on type, see above)
+* assigned participant for agency
+
 ## /shipcall PUT
 
 1. The call may only be performed by a user belonging to participant group type BSMD.
@@ -105,6 +112,10 @@ In other words: no setting the agency and editing the record by a member of the
 3. See value rules in /shipcall POST. Exception: Canceled may be set but only if not already set.
 4. A cancelled shipcall may not be changed (is logical delete)
 
+#### Required fields
+
+The id field is required, missing fields will not be updated.
+
 ## /times POST
 
 1. A new dataset may only be created by a user _not_ belonging to participant group BSMD.
@@ -125,12 +136,50 @@ In other words: no setting the agency and editing the record by a member of the
     | remarks, berth_info | must be <= 512 chars |
     | participant_type | must not be BSMD |
 
+#### Required fields
+
+This depends on the shipcall and participant type:
+
+##### Incoming
+
+AGENCY, PILOT, PORT_AUTHORITY, MOORING, TUG:
+
+eta_berth, shipcall_id, participant_id, participant_type
+
+TERMINAL:
+
+operations_start, shipcall_id, participant_id, participant_type
+
+##### Outgoing
+
+AGENCY, PILOT, PORT_AUTHORITY, MOORING, TUG:
+
+etd_berth, shipcall_id, participant_id, participant_type
+
+TERMINAL:
+
+operations_end, shipcall_id, participant_id, participant_type
+
+##### Shifting
+
+AGENCY, PILOT, PORT_AUTHORITY, MOORING, TUG:
+
+eta_berth, etd_berth, shipcall_id, participant_id, participant_type
+
+TERMINAL:
+
+operations_start, operations_end, shipcall_id, participant_id, participant_type
+
 
 ## /times PUT
 
 1. A dataset may only be changed by a user belonging to the same participant as the times dataset is referring to.
 2. See reference and value checking as specified in /times POST.
 
+#### Required fields
+
+The id field is required, missing fields will not be updated.
+
 ## /times DELETE
 
 1. A dataset may only be changed by a user belonging to the same participant as the times dataset is referring to.
@@ -155,7 +204,8 @@ In other words: no setting the agency and editing the record by a member of the
 
 1. The call may only be performed by a user belonging to participant group type BSMD.
 2. The IMO number field may not be changed since it serves the purpose of a primary (matching) key.
-3. See value rules in /ship POST.
+3. See value rules in /ship POST
+4. The id field is required, missing fields will not be updated
 
 
 ## /ship DELETE