diff --git a/nullptr/central_command.py b/nullptr/central_command.py
index cd87dad..7c6f590 100644
--- a/nullptr/central_command.py
+++ b/nullptr/central_command.py
@@ -30,14 +30,6 @@ class CentralCommand:
     mission = self.missions[ship]
     mission.step()
     return True
-  
-  def wait_for_stop(self):
-    try:
-      input()
-    except EOFError:
-      pass
-    self.stopping = True
-    print('stopping...')
     
   def run_interactive(self):
     print('auto mode. hit enter to stop')
@@ -46,7 +38,17 @@ class CentralCommand:
     t.start()
     self.run()
     print('manual mode')
-    
+  
+  
+  def wait_for_stop(self):
+    try:
+      input()
+    except EOFError:
+      pass
+    self.stopping = True
+    print('stopping...')
+  
+  
   def run(self):
     self.update_missions()
     while not self.stopping:
diff --git a/nullptr/commander.py b/nullptr/commander.py
index 8b84e92..1a223f6 100644
--- a/nullptr/commander.py
+++ b/nullptr/commander.py
@@ -123,6 +123,8 @@ class Commander(CommandLine):
   
   def do_chaul(self):
     if not self.has_ship(): return     
+    if len(ship.cargo) > 0:
+      raise CommandError('please dump cargo first')
     contract = self.active_contract()
     delivery = contract.unfinished_delivery()
     if delivery is None:
diff --git a/nullptr/models/marketplace.py b/nullptr/models/marketplace.py
index 6ae0e98..ca6e4ae 100644
--- a/nullptr/models/marketplace.py
+++ b/nullptr/models/marketplace.py
@@ -25,6 +25,7 @@ class Marketplace(SystemMember):
         price['symbol'] = symbol
         price['buy'] = mg(g, 'purchasePrice')
         price['sell'] = mg(g, 'sellPrice')
+        price['volume'] = mg(g, 'tradeVolume')
         prices[symbol] = price
       self.prices = prices