diff --git a/apps/openmw/mwclass/apparatus.cpp b/apps/openmw/mwclass/apparatus.cpp
index 878c9f59e..2a007d6ad 100644
--- a/apps/openmw/mwclass/apparatus.cpp
+++ b/apps/openmw/mwclass/apparatus.cpp
@@ -149,10 +149,9 @@ namespace MWClass
         return (npcServices & ESM::NPC::Apparatus) != 0;
     }
 
-    float Apparatus::getWeight(const MWWorld::Ptr &ptr) const
+    float Apparatus::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Apparatus> *ref =
-            ptr.get<ESM::Apparatus>();
+        const MWWorld::LiveCellRef<ESM::Apparatus> *ref = ptr.get<ESM::Apparatus>();
         return ref->mBase->mData.mWeight;
     }
 }
diff --git a/apps/openmw/mwclass/apparatus.hpp b/apps/openmw/mwclass/apparatus.hpp
index c5066d0fc..240bf8dea 100644
--- a/apps/openmw/mwclass/apparatus.hpp
+++ b/apps/openmw/mwclass/apparatus.hpp
@@ -16,7 +16,7 @@ namespace MWClass
             /// Return ID of \a ptr
             virtual std::string getId (const MWWorld::Ptr& ptr) const;
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual void insertObjectRendering (const MWWorld::Ptr& ptr, const std::string& model, MWRender::RenderingInterface& renderingInterface) const;
             ///< Add reference into a cell for rendering
diff --git a/apps/openmw/mwclass/armor.cpp b/apps/openmw/mwclass/armor.cpp
index 0554c738e..8cd4a98e6 100644
--- a/apps/openmw/mwclass/armor.cpp
+++ b/apps/openmw/mwclass/armor.cpp
@@ -388,10 +388,9 @@ namespace MWClass
                 || ((npcServices & ESM::NPC::MagicItems) && !getEnchantment(item).empty());
     }
 
-    float Armor::getWeight(const MWWorld::Ptr &ptr) const
+    float Armor::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Armor> *ref =
-            ptr.get<ESM::Armor>();
+        const MWWorld::LiveCellRef<ESM::Armor> *ref = ptr.get<ESM::Armor>();
         return ref->mBase->mData.mWeight;
     }
 }
diff --git a/apps/openmw/mwclass/armor.hpp b/apps/openmw/mwclass/armor.hpp
index 4fd426da4..c06c1689f 100644
--- a/apps/openmw/mwclass/armor.hpp
+++ b/apps/openmw/mwclass/armor.hpp
@@ -15,7 +15,7 @@ namespace MWClass
             /// Return ID of \a ptr
             virtual std::string getId (const MWWorld::Ptr& ptr) const;
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual void insertObjectRendering (const MWWorld::Ptr& ptr, const std::string& model, MWRender::RenderingInterface& renderingInterface) const;
             ///< Add reference into a cell for rendering
diff --git a/apps/openmw/mwclass/book.cpp b/apps/openmw/mwclass/book.cpp
index 9ef9b769e..372dc084f 100644
--- a/apps/openmw/mwclass/book.cpp
+++ b/apps/openmw/mwclass/book.cpp
@@ -196,10 +196,9 @@ namespace MWClass
                 || ((npcServices & ESM::NPC::MagicItems) && !getEnchantment(item).empty());
     }
 
-    float Book::getWeight(const MWWorld::Ptr &ptr) const
+    float Book::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Book> *ref =
-            ptr.get<ESM::Book>();
+        const MWWorld::LiveCellRef<ESM::Book> *ref = ptr.get<ESM::Book>();
         return ref->mBase->mData.mWeight;
     }
 }
diff --git a/apps/openmw/mwclass/book.hpp b/apps/openmw/mwclass/book.hpp
index 21c9a018d..0452dd6f1 100644
--- a/apps/openmw/mwclass/book.hpp
+++ b/apps/openmw/mwclass/book.hpp
@@ -64,7 +64,7 @@ namespace MWClass
 
             virtual int getEnchantmentPoints (const MWWorld::Ptr& ptr) const;
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
diff --git a/apps/openmw/mwclass/clothing.cpp b/apps/openmw/mwclass/clothing.cpp
index f5000229b..7b32377f6 100644
--- a/apps/openmw/mwclass/clothing.cpp
+++ b/apps/openmw/mwclass/clothing.cpp
@@ -284,10 +284,9 @@ namespace MWClass
                 || ((npcServices & ESM::NPC::MagicItems) && !getEnchantment(item).empty());
     }
 
-    float Clothing::getWeight(const MWWorld::Ptr &ptr) const
+    float Clothing::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Clothing> *ref =
-            ptr.get<ESM::Clothing>();
+        const MWWorld::LiveCellRef<ESM::Clothing> *ref = ptr.get<ESM::Clothing>();
         return ref->mBase->mData.mWeight;
     }
 }
diff --git a/apps/openmw/mwclass/clothing.hpp b/apps/openmw/mwclass/clothing.hpp
index 4c0240e74..fdf7b1493 100644
--- a/apps/openmw/mwclass/clothing.hpp
+++ b/apps/openmw/mwclass/clothing.hpp
@@ -77,7 +77,7 @@ namespace MWClass
 
             virtual int getEnchantmentPoints (const MWWorld::Ptr& ptr) const;
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
diff --git a/apps/openmw/mwclass/ingredient.cpp b/apps/openmw/mwclass/ingredient.cpp
index 5c2cabd4c..67d85458d 100644
--- a/apps/openmw/mwclass/ingredient.cpp
+++ b/apps/openmw/mwclass/ingredient.cpp
@@ -187,10 +187,9 @@ namespace MWClass
     }
 
 
-    float Ingredient::getWeight(const MWWorld::Ptr &ptr) const
+    float Ingredient::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Ingredient> *ref =
-            ptr.get<ESM::Ingredient>();
+        const MWWorld::LiveCellRef<ESM::Ingredient> *ref = ptr.get<ESM::Ingredient>();
         return ref->mBase->mData.mWeight;
     }
 }
diff --git a/apps/openmw/mwclass/ingredient.hpp b/apps/openmw/mwclass/ingredient.hpp
index dddf538d1..46695e52d 100644
--- a/apps/openmw/mwclass/ingredient.hpp
+++ b/apps/openmw/mwclass/ingredient.hpp
@@ -57,7 +57,7 @@ namespace MWClass
 
             virtual std::string getModel(const MWWorld::ConstPtr &ptr) const;
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
diff --git a/apps/openmw/mwclass/light.cpp b/apps/openmw/mwclass/light.cpp
index 46ddeeb5f..21277c038 100644
--- a/apps/openmw/mwclass/light.cpp
+++ b/apps/openmw/mwclass/light.cpp
@@ -218,10 +218,9 @@ namespace MWClass
         return (npcServices & ESM::NPC::Lights) != 0;
     }
 
-    float Light::getWeight(const MWWorld::Ptr &ptr) const
+    float Light::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Light> *ref =
-            ptr.get<ESM::Light>();
+        const MWWorld::LiveCellRef<ESM::Light> *ref = ptr.get<ESM::Light>();
         return ref->mBase->mData.mWeight;
     }
 
diff --git a/apps/openmw/mwclass/light.hpp b/apps/openmw/mwclass/light.hpp
index f0061117b..669e7e1e0 100644
--- a/apps/openmw/mwclass/light.hpp
+++ b/apps/openmw/mwclass/light.hpp
@@ -67,7 +67,7 @@ namespace MWClass
 
             virtual std::string getModel(const MWWorld::ConstPtr &ptr) const;
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
diff --git a/apps/openmw/mwclass/lockpick.cpp b/apps/openmw/mwclass/lockpick.cpp
index 26f7fba10..80982c471 100644
--- a/apps/openmw/mwclass/lockpick.cpp
+++ b/apps/openmw/mwclass/lockpick.cpp
@@ -174,10 +174,9 @@ namespace MWClass
         return ref->mBase->mData.mUses;
     }
 
-    float Lockpick::getWeight(const MWWorld::Ptr &ptr) const
+    float Lockpick::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Lockpick> *ref =
-            ptr.get<ESM::Lockpick>();
+        const MWWorld::LiveCellRef<ESM::Lockpick> *ref = ptr.get<ESM::Lockpick>();
         return ref->mBase->mData.mWeight;
     }
 }
diff --git a/apps/openmw/mwclass/lockpick.hpp b/apps/openmw/mwclass/lockpick.hpp
index e06060172..da6f824ec 100644
--- a/apps/openmw/mwclass/lockpick.hpp
+++ b/apps/openmw/mwclass/lockpick.hpp
@@ -63,7 +63,7 @@ namespace MWClass
 
             virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual int getItemMaxHealth (const MWWorld::ConstPtr& ptr) const;
             ///< Return item max health or throw an exception, if class does not have item health
diff --git a/apps/openmw/mwclass/misc.cpp b/apps/openmw/mwclass/misc.cpp
index aba92ae3d..8dad332b6 100644
--- a/apps/openmw/mwclass/misc.cpp
+++ b/apps/openmw/mwclass/misc.cpp
@@ -235,10 +235,9 @@ namespace MWClass
         return !ref->mBase->mData.mIsKey && (npcServices & ESM::NPC::Misc) && !isGold(item);
     }
 
-    float Miscellaneous::getWeight(const MWWorld::Ptr &ptr) const
+    float Miscellaneous::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Miscellaneous> *ref =
-            ptr.get<ESM::Miscellaneous>();
+        const MWWorld::LiveCellRef<ESM::Miscellaneous> *ref = ptr.get<ESM::Miscellaneous>();
         return ref->mBase->mData.mWeight;
     }
 
diff --git a/apps/openmw/mwclass/misc.hpp b/apps/openmw/mwclass/misc.hpp
index bc15f2c5f..64e7c6e6d 100644
--- a/apps/openmw/mwclass/misc.hpp
+++ b/apps/openmw/mwclass/misc.hpp
@@ -57,7 +57,7 @@ namespace MWClass
                 const;
             ///< Generate action for using via inventory menu
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
diff --git a/apps/openmw/mwclass/potion.cpp b/apps/openmw/mwclass/potion.cpp
index 8ca8e5111..24f7aae2d 100644
--- a/apps/openmw/mwclass/potion.cpp
+++ b/apps/openmw/mwclass/potion.cpp
@@ -180,10 +180,9 @@ namespace MWClass
         return (npcServices & ESM::NPC::Potions) != 0;
     }
 
-    float Potion::getWeight(const MWWorld::Ptr &ptr) const
+    float Potion::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Potion> *ref =
-            ptr.get<ESM::Potion>();
+        const MWWorld::LiveCellRef<ESM::Potion> *ref = ptr.get<ESM::Potion>();
         return ref->mBase->mData.mWeight;
     }
 }
diff --git a/apps/openmw/mwclass/potion.hpp b/apps/openmw/mwclass/potion.hpp
index c4e9dba3d..a0c4b97df 100644
--- a/apps/openmw/mwclass/potion.hpp
+++ b/apps/openmw/mwclass/potion.hpp
@@ -56,7 +56,7 @@ namespace MWClass
 
             virtual std::string getModel(const MWWorld::ConstPtr &ptr) const;
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
diff --git a/apps/openmw/mwclass/probe.cpp b/apps/openmw/mwclass/probe.cpp
index 89b7f0ab5..6757c6ed2 100644
--- a/apps/openmw/mwclass/probe.cpp
+++ b/apps/openmw/mwclass/probe.cpp
@@ -174,10 +174,9 @@ namespace MWClass
         return ref->mBase->mData.mUses;
     }
 
-    float Probe::getWeight(const MWWorld::Ptr &ptr) const
+    float Probe::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Probe> *ref =
-            ptr.get<ESM::Probe>();
+        const MWWorld::LiveCellRef<ESM::Probe> *ref = ptr.get<ESM::Probe>();
         return ref->mBase->mData.mWeight;
     }
 }
diff --git a/apps/openmw/mwclass/probe.hpp b/apps/openmw/mwclass/probe.hpp
index 79f1831b3..0c971c914 100644
--- a/apps/openmw/mwclass/probe.hpp
+++ b/apps/openmw/mwclass/probe.hpp
@@ -63,7 +63,7 @@ namespace MWClass
 
             virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual int getItemMaxHealth (const MWWorld::ConstPtr& ptr) const;
             ///< Return item max health or throw an exception, if class does not have item health
diff --git a/apps/openmw/mwclass/repair.cpp b/apps/openmw/mwclass/repair.cpp
index 3e6bcca95..83162462f 100644
--- a/apps/openmw/mwclass/repair.cpp
+++ b/apps/openmw/mwclass/repair.cpp
@@ -166,10 +166,9 @@ namespace MWClass
         return (npcServices & ESM::NPC::RepairItem) != 0;
     }
 
-    float Repair::getWeight(const MWWorld::Ptr &ptr) const
+    float Repair::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Repair> *ref =
-            ptr.get<ESM::Repair>();
+        const MWWorld::LiveCellRef<ESM::Repair> *ref = ptr.get<ESM::Repair>();
         return ref->mBase->mData.mWeight;
     }
 }
diff --git a/apps/openmw/mwclass/repair.hpp b/apps/openmw/mwclass/repair.hpp
index 0e9c21cdb..44b845d69 100644
--- a/apps/openmw/mwclass/repair.hpp
+++ b/apps/openmw/mwclass/repair.hpp
@@ -65,7 +65,7 @@ namespace MWClass
             ///< Return item max health or throw an exception, if class does not have item health
             /// (default implementation: throw an exception)
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
     };
diff --git a/apps/openmw/mwclass/weapon.cpp b/apps/openmw/mwclass/weapon.cpp
index 3a827088c..a45eaaa33 100644
--- a/apps/openmw/mwclass/weapon.cpp
+++ b/apps/openmw/mwclass/weapon.cpp
@@ -425,10 +425,9 @@ namespace MWClass
                 || ((npcServices & ESM::NPC::MagicItems) && !getEnchantment(item).empty());
     }
 
-    float Weapon::getWeight(const MWWorld::Ptr &ptr) const
+    float Weapon::getWeight(const MWWorld::ConstPtr &ptr) const
     {
-        MWWorld::LiveCellRef<ESM::Weapon> *ref =
-            ptr.get<ESM::Weapon>();
+        const MWWorld::LiveCellRef<ESM::Weapon> *ref = ptr.get<ESM::Weapon>();
         return ref->mBase->mData.mWeight;
     }
 }
diff --git a/apps/openmw/mwclass/weapon.hpp b/apps/openmw/mwclass/weapon.hpp
index 29222bb5d..0582d9892 100644
--- a/apps/openmw/mwclass/weapon.hpp
+++ b/apps/openmw/mwclass/weapon.hpp
@@ -83,7 +83,7 @@ namespace MWClass
 
             virtual bool canSell (const MWWorld::ConstPtr& item, int npcServices) const;
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual int getEnchantmentPoints (const MWWorld::Ptr& ptr) const;
     };
diff --git a/apps/openmw/mwworld/class.cpp b/apps/openmw/mwworld/class.cpp
index 9111215d2..f19dce5d0 100644
--- a/apps/openmw/mwworld/class.cpp
+++ b/apps/openmw/mwworld/class.cpp
@@ -208,7 +208,7 @@ namespace MWWorld
         throw std::runtime_error ("capacity not supported by this class");
     }
 
-    float Class::getWeight(const Ptr &ptr) const
+    float Class::getWeight(const ConstPtr &ptr) const
     {
         throw std::runtime_error ("weight not supported by this class");
     }
diff --git a/apps/openmw/mwworld/class.hpp b/apps/openmw/mwworld/class.hpp
index 8d64f9cbe..0a8265404 100644
--- a/apps/openmw/mwworld/class.hpp
+++ b/apps/openmw/mwworld/class.hpp
@@ -275,7 +275,7 @@ namespace MWWorld
             ///< Return 0 if player cannot equip item. 1 if can equip. 2 if it's twohanded weapon. 3 if twohanded weapon conflicts with that.
             ///  Second item in the pair specifies the error message
 
-            virtual float getWeight (const MWWorld::Ptr& ptr) const;
+            virtual float getWeight (const MWWorld::ConstPtr& ptr) const;
 
             virtual bool isPersistent (const MWWorld::Ptr& ptr) const;