diff --git a/nullptr/analyzer.py b/nullptr/analyzer.py
index 53ad12c..03f8074 100644
--- a/nullptr/analyzer.py
+++ b/nullptr/analyzer.py
@@ -44,16 +44,16 @@ class Analyzer:
       location = self.store.get(Waypoint, location)
     mkts = self.find_markets(resource, sellbuy)
     candidates = []
-    origin = self.store.get(System, location.system())
+    origin = location.system
     for typ, m in mkts:
-      system = self.store.get(System, m.system())
+      system = m.waypoint.system
       d = origin.distance(system)
       candidates.append((typ, m, d))
     possibles = sorted(candidates, key=lambda m: m[2])
     possibles = possibles[:10]
     results = []
     for typ,m,d in possibles:
-      system = self.store.get(System, m.system())
+      system = m.waypoint.system
       p = self.find_path(origin, system)
       if p is None: continue
       results.append((typ,m,d,len(p)))
diff --git a/nullptr/commander.py b/nullptr/commander.py
index 7b12842..d4c509c 100644
--- a/nullptr/commander.py
+++ b/nullptr/commander.py
@@ -121,7 +121,7 @@ class Commander(CommandLine):
   
   def do_chaul(self):
     if not self.has_ship(): return     
-    if len(ship.cargo) > 0:
+    if len(self.ship.cargo) > 0:
       raise CommandError('please dump cargo first')
     contract = self.active_contract()
     delivery = contract.unfinished_delivery()
diff --git a/nullptr/missions/base.py b/nullptr/missions/base.py
index e509dfd..702b2b6 100644
--- a/nullptr/missions/base.py
+++ b/nullptr/missions/base.py
@@ -28,7 +28,10 @@ class MissionParam:
     elif self.cls == list:
       return [i.strip() for i in val.split(',')]
     elif issubclass(self.cls, Base):
-      data = store.get(self.cls, val)
+      if type(val) == str:
+        data = store.get(self.cls, val)
+      else:
+        data = val
       if data is None:
         raise ValueError('object not found')
       return data.symbol
@@ -179,9 +182,8 @@ class BaseMission(Mission):
     traject = self.st('traject')
     if traject is None or traject == []:
       return 'done'
-    dest = self.store.get(Waypoint, traject[-1])
-    loc = self.ship.location()
-    print(dest, loc)
+    dest = traject[-1]
+    loc = self.ship.location
     if dest == loc:
       self.sts('traject', None)
       return 'done'
@@ -200,10 +202,10 @@ class BaseMission(Mission):
   def step_calculate_traject(self, dest):
     if type(dest) == str:
       dest = self.store.get(Waypoint, dest)
-    loc = self.ship.location()
-    loc_sys = self.store.get(System, loc.system())
+    loc = self.ship.location
+    loc_sys = loc.system
     loc_jg = self.analyzer.get_jumpgate(loc_sys)
-    dest_sys = self.store.get(System, dest.system())
+    dest_sys = dest.system
     dest_jg = self.analyzer.get_jumpgate(dest_sys)
     if dest_sys == loc_sys:
       result = [dest.symbol]
@@ -212,10 +214,10 @@ class BaseMission(Mission):
     path = self.analyzer.find_path(loc_sys, dest_sys)
     result = []
     if loc.symbol != loc_jg.symbol:
-      result.append(loc_jg.symbol)
+      result.append(loc_jg)
     result += [s.symbol for s in path[1:]]
     if dest_jg.symbol != dest.symbol:
-      result.append(dest.symbol)
+      result.append(dest)
     self.sts('traject', result)
     print(result)
     return result
diff --git a/nullptr/models/__init__.py b/nullptr/models/__init__.py
index f919fce..c9063dc 100644
--- a/nullptr/models/__init__.py
+++ b/nullptr/models/__init__.py
@@ -9,4 +9,4 @@ from nullptr.models.ship import Ship
 from nullptr.models.contract import Contract
 from nullptr.models.survey import Survey
 
-__all__ = [ 'Waypoint', 'Sector', 'Ship', 'Survey', 'Agent', 'Marketplace', 'Jumpgate', 'Contract', 'Base' ]
+__all__ = [ 'Waypoint', 'Sector', 'Ship', 'Survey', 'System', 'Agent', 'Marketplace', 'Jumpgate', 'Contract', 'Base' ]
diff --git a/nullptr/models/base.py b/nullptr/models/base.py
index 4efd2e5..883f690 100644
--- a/nullptr/models/base.py
+++ b/nullptr/models/base.py
@@ -23,7 +23,7 @@ class Base:
   
   def __init__(self, symbol, store):
     self.disable_dirty = True
-    self.file_offset = 0
+    self.file_offset = None
     self.store = store
     self.symbol = symbol
     self.define()
diff --git a/nullptr/models/marketplace.py b/nullptr/models/marketplace.py
index 5187cdf..b71c9c9 100644
--- a/nullptr/models/marketplace.py
+++ b/nullptr/models/marketplace.py
@@ -3,6 +3,7 @@ from .base import Base
 from time import time
 from nullptr.util import *
 from dataclasses import field
+from nullptr.models import Waypoint
 
 class Marketplace(Base):
   def define(self):
@@ -11,6 +12,11 @@ class Marketplace(Base):
     self.exchange:list = []
     self.prices:dict = {}
     self.last_prices:int = 0
+    self.set_waypoint()
+  
+  def set_waypoint(self):
+    waypoint = self.store.get(Waypoint, self.symbol, create=True)
+    self.waypoint = waypoint
   
   def update(self, d):
     self.setlst('imports', d, 'imports', 'symbol')
diff --git a/nullptr/models/ship.py b/nullptr/models/ship.py
index 5172f04..2350d1b 100644
--- a/nullptr/models/ship.py
+++ b/nullptr/models/ship.py
@@ -1,7 +1,7 @@
 from .base import Base
 from time import time
 from nullptr.util import *
-from dataclasses import dataclass, field
+from nullptr.models import Waypoint
 
 class Ship(Base):  
   def define(self):
@@ -10,7 +10,7 @@ class Ship(Base):
     self.status:str = ''
     self.cargo_capacity:int = 0
     self.cargo_units:int = 0
-    self.location_str = ''
+    self.location = None
     self.cooldown:int = 0
     self.arrival:int = 0
     self.fuel_current:int = 0
@@ -21,9 +21,6 @@ class Ship(Base):
   @classmethod
   def ext(self):
     return 'shp'
-  
-  def location(self):
-    return self.store.get('Waypoint', self.location_str)
     
   def path(self):
     agent = self.symbol.split('-')[0]
@@ -31,7 +28,8 @@ class Ship(Base):
 
   def update(self, d):
     self.seta('status', d, 'nav.status')
-    self.seta('location_str', d, 'nav.waypointSymbol')
+    getter = self.store.getter(Waypoint, create=True)
+    self.seta('location', d, 'nav.waypointSymbol', interp=getter)
     self.seta('cargo_capacity', d, 'cargo.capacity')
     self.seta('cargo_units', d, 'cargo.units')
     self.seta('fuel_capacity', d, 'fuel.capacity')
@@ -95,7 +93,7 @@ class Ship(Base):
     if detail > 1:
       r += ' ' + self.status
       r += f' [{self.fuel_current}/{self.fuel_capacity}]'
-      r += ' ' + str(self.location())
+      r += ' ' + str(self.location)
       if self.is_travelling():
         r += f' [A: {arrival}]'
       if self.is_cooldown():
diff --git a/nullptr/store.py b/nullptr/store.py
index e581c47..2328fb9 100644
--- a/nullptr/store.py
+++ b/nullptr/store.py
@@ -27,17 +27,19 @@ class StoreUnpickler(pickle.Unpickler):
         
 class ChunkHeader:
   def __init__(self):
+    self.offset = 0
     self.in_use = True
     self.size = 0
     self.used = 0
     
   @classmethod
   def parse(cls, fil):
+    offset = fil.tell()
     d = fil.read(16)
     if len(d) < 16:
       return None
-    #  print(d)
     o = cls()
+    o.offset = offset
     d, o.used = unpack('<QQ', d)
     o.size =   d & 0x7fffffffffffffff
     o.in_use = d & 0x8000000000000000 != 0
@@ -97,7 +99,10 @@ class Store:
     self.fil.seek(0)
     offset = 0
     while (hdr := ChunkHeader.parse(self.fil)):
-      if not hdr.in_use: continue
+      print(hdr)
+      if not hdr.in_use: 
+        self.fil.seek(hdr.size, 1)
+        continue
       data = self.fil.read(hdr.used)
       self.load_object(data, offset)
       self.fil.seek(hdr.size - hdr.used, 1)
@@ -118,6 +123,7 @@ class Store:
     h = ChunkHeader()
     h.size = sz
     h.used = used
+    h.offset = self.fil.tell()
     h.write(self.fil)
     return offset, h
     
@@ -125,7 +131,7 @@ class Store:
     data = self.dump_object(obj)
     osize = len(data)
     # is there an existing chunk for this obj?
-    if obj.file_offset > 0:
+    if obj.file_offset is not None:
       # read chunk hdr
       self.fil.seek(obj.file_offset)
       hdr = ChunkHeader.parse(self.fil)
@@ -135,15 +141,16 @@ class Store:
         # free the chunk
         hdr.in_use = False
         # force a new chunk
-        obj.file_offset = 0
+        obj.file_offset = None
       else:
         # if it is big enough, update the used field
         hdr.used = osize
-      self.fil.seek(obj.file_offset)
+      self.fil.seek(hdr.offset)
       hdr.write(self.fil)
         
-    if obj.file_offset == 0:
+    if obj.file_offset is None:
       obj.file_offset, hdr = self.allocate_chunk(osize)
+    print(type(obj).__name__, hdr)
     self.fil.write(data)
     slack = b'\x00' * (hdr.size - hdr.used)
     self.fil.write(slack)
@@ -181,7 +188,7 @@ class Store:
   def getter(self, typ, create=False):
     if type(typ) == str and typ in self.model_names:
       typ = self.model_names[typ]
-    return partial(self.get, typ=typ, create=create)
+    return partial(self.get, typ, create=create)
   
   def update(self, typ, data, symbol=None):
     if type(typ) == str and typ in self.model_names: