diff --git a/src/server/BreCal/schemas/model.py b/src/server/BreCal/schemas/model.py
index 2b096c1..6ee4104 100644
--- a/src/server/BreCal/schemas/model.py
+++ b/src/server/BreCal/schemas/model.py
@@ -17,7 +17,7 @@ class Berth(Schema):
     id: int
     name: str
     participant_id: int
-    lock: bool
+    lock: bool # synonyms: lock/sluice/floodgate
     created: datetime
     modified: datetime
     deleted: bool
@@ -94,7 +94,7 @@ class Shipcall:
 
     id: int
     ship_id: int
-    type: str
+    type: str # in other classes, type is an integer (same in ShipcallSchema). Is str correct here?
     eta: datetime
     voyage: str
     etd: datetime
@@ -203,6 +203,7 @@ class Ship(Schema):
     participant_id: int
     length: float
     width: float
+    # TODO: determine, if max_draft is missing. Was initially listed in 'BremenCalling_Datenmodell.xlsx'
     is_tug: bool
     bollard_pull: int
     eni: str