diff --git a/src/OpenFOAM/containers/Lists/UPtrList/UPtrList.H b/src/OpenFOAM/containers/Lists/UPtrList/UPtrList.H
index 4ed912500b..3fd58746fa 100644
--- a/src/OpenFOAM/containers/Lists/UPtrList/UPtrList.H
+++ b/src/OpenFOAM/containers/Lists/UPtrList/UPtrList.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -54,62 +54,6 @@ template<class T> class PtrList;
 // Forward declaration of friend functions and operators
 template<class T> class UPtrList;
 
-template<class T>
-inline typename UPtrList<T>::iterator operator+
-(
-    const typename UPtrList<T>::iterator&,
-    label
-);
-
-template<class T>
-inline typename UPtrList<T>::iterator operator+
-(
-    label,
-    const typename UPtrList<T>::iterator&
-);
-
-template<class T>
-inline typename UPtrList<T>::iterator operator-
-(
-    const typename UPtrList<T>::iterator&,
-    label
-);
-
-template<class T>
-inline label operator-
-(
-    const typename UPtrList<T>::iterator&,
-    const typename UPtrList<T>::iterator&
-);
-
-template<class T>
-inline typename UPtrList<T>::const_iterator operator+
-(
-    const typename UPtrList<T>::const_iterator&,
-    label
-);
-
-template<class T>
-inline typename UPtrList<T>::const_iterator operator+
-(
-    label,
-    const typename UPtrList<T>::const_iterator&
-);
-
-template<class T>
-inline typename UPtrList<T>::const_iterator operator-
-(
-    const typename UPtrList<T>::const_iterator&,
-    label
-);
-
-template<class T>
-inline label operator-
-(
-    const typename UPtrList<T>::const_iterator&,
-    const typename UPtrList<T>::const_iterator&
-);
-
 template<class T>
 Istream& operator>>(Istream&, UPtrList<T>&);
 
@@ -239,6 +183,7 @@ public:
     // Random access iterator for traversing UPtrList
 
         class iterator;
+        class const_iterator;
         friend class iterator;
 
         //- An STL iterator
@@ -248,6 +193,8 @@ public:
 
         public:
 
+            friend class const_iterator;
+
             //- Construct for a given UPtrList entry
             inline iterator(T**);
 
@@ -260,27 +207,20 @@ public:
                 inline T& operator()();
 
                 inline iterator operator++();
-                inline iterator operator++(int);
+                inline iterator operator++(const int);
 
                 inline iterator operator--();
-                inline iterator operator--(int);
+                inline iterator operator--(const int);
 
-                inline iterator operator+=(label);
+                inline iterator operator+=(const label);
+                inline iterator operator-=(const label);
 
-                friend iterator operator+ <T>(const iterator&, label);
-                friend iterator operator+ <T>(label, const iterator&);
+                inline iterator operator+(const label) const;
+                inline iterator operator-(const label) const;
 
-                inline iterator operator-=(label);
+                inline label operator-(const iterator&) const;
 
-                friend iterator operator- <T>(const iterator&, label);
-
-                friend label operator- <T>
-                (
-                    const iterator&,
-                    const iterator&
-                );
-
-                inline T& operator[](label);
+                inline T& operator[](const label);
 
                 inline bool operator<(const iterator&) const;
                 inline bool operator>(const iterator&) const;
@@ -323,39 +263,20 @@ public:
                 inline Tref operator()();
 
                 inline const_iterator operator++();
-                inline const_iterator operator++(int);
+                inline const_iterator operator++(const int);
 
                 inline const_iterator operator--();
-                inline const_iterator operator--(int);
+                inline const_iterator operator--(const int);
 
-                inline const_iterator operator+=(label);
+                inline const_iterator operator+=(const label);
+                inline const_iterator operator-=(const label);
 
-                friend const_iterator operator+ <T>
-                (
-                    const const_iterator&,
-                    label
-                );
-                friend const_iterator operator+ <T>
-                (
-                    label,
-                    const const_iterator&
-                );
+                inline const_iterator operator+(const label) const;
+                inline const_iterator operator-(const label) const;
 
-                inline const_iterator operator-=(label);
+                inline label operator-(const const_iterator&) const;
 
-                friend const_iterator operator- <T>
-                (
-                    const const_iterator&,
-                    label
-                );
-
-                friend label operator- <T>
-                (
-                    const const_iterator&,
-                    const const_iterator&
-                );
-
-                inline const T& operator[](label);
+                inline const T& operator[](const label);
 
                 inline bool operator<(const const_iterator&) const;
                 inline bool operator>(const const_iterator&) const;
diff --git a/src/OpenFOAM/containers/Lists/UPtrList/UPtrListI.H b/src/OpenFOAM/containers/Lists/UPtrList/UPtrListI.H
index 191ae39da7..ae6cb38ab1 100644
--- a/src/OpenFOAM/containers/Lists/UPtrList/UPtrListI.H
+++ b/src/OpenFOAM/containers/Lists/UPtrList/UPtrListI.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -146,30 +146,35 @@ inline Foam::UPtrList<T>::iterator::iterator(T** ptr)
     ptr_(ptr)
 {}
 
+
 template<class T>
 inline bool Foam::UPtrList<T>::iterator::operator==(const iterator& iter) const
 {
     return ptr_ == iter.ptr_;
 }
 
+
 template<class T>
 inline bool Foam::UPtrList<T>::iterator::operator!=(const iterator& iter) const
 {
     return ptr_ != iter.ptr_;
 }
 
+
 template<class T>
 inline T& Foam::UPtrList<T>::iterator::operator*()
 {
     return **ptr_;
 }
 
+
 template<class T>
 inline T& Foam::UPtrList<T>::iterator::operator()()
 {
     return operator*();
 }
 
+
 template<class T>
 inline typename Foam::UPtrList<T>::iterator
 Foam::UPtrList<T>::iterator::operator++()
@@ -178,15 +183,17 @@ Foam::UPtrList<T>::iterator::operator++()
     return *this;
 }
 
+
 template<class T>
 inline typename Foam::UPtrList<T>::iterator
-Foam::UPtrList<T>::iterator::operator++(int)
+Foam::UPtrList<T>::iterator::operator++(const int)
 {
     iterator tmp = *this;
     ++ptr_;
     return tmp;
 }
 
+
 template<class T>
 inline typename Foam::UPtrList<T>::iterator
 Foam::UPtrList<T>::iterator::operator--()
@@ -195,95 +202,98 @@ Foam::UPtrList<T>::iterator::operator--()
     return *this;
 }
 
+
 template<class T>
 inline typename Foam::UPtrList<T>::iterator
-Foam::UPtrList<T>::iterator::operator--(int)
+Foam::UPtrList<T>::iterator::operator--(const int)
 {
     iterator tmp = *this;
     --ptr_;
     return tmp;
 }
 
+
 template<class T>
 inline typename Foam::UPtrList<T>::iterator
-Foam::UPtrList<T>::iterator::operator+=(label n)
+Foam::UPtrList<T>::iterator::operator+=(const label n)
 {
     ptr_ += n;
     return *this;
 }
 
-template<class T>
-inline typename Foam::UPtrList<T>::iterator
-Foam::operator+(const typename UPtrList<T>::iterator& iter, label n)
-{
-    typename UPtrList<T>::iterator tmp = iter;
-    return tmp += n;
-}
 
 template<class T>
 inline typename Foam::UPtrList<T>::iterator
-Foam::operator+(label n, const typename UPtrList<T>::iterator& iter)
-{
-    typename UPtrList<T>::iterator tmp = iter;
-    return tmp += n;
-}
-
-template<class T>
-inline typename Foam::UPtrList<T>::iterator
-Foam::UPtrList<T>::iterator::operator-=(label n)
+Foam::UPtrList<T>::iterator::operator-=(const label n)
 {
     ptr_ -= n;
     return *this;
 }
 
+
 template<class T>
 inline typename Foam::UPtrList<T>::iterator
-Foam::operator-(const typename UPtrList<T>::iterator& iter, label n)
+Foam::UPtrList<T>::iterator::operator+(const label n) const
 {
-    typename UPtrList<T>::iterator tmp = iter;
+    typename UPtrList<T>::iterator tmp = *this;
+    return tmp += n;
+}
+
+
+template<class T>
+inline typename Foam::UPtrList<T>::iterator
+Foam::UPtrList<T>::iterator::operator-(const label n) const
+{
+    typename UPtrList<T>::iterator tmp = *this;
     return tmp -= n;
 }
 
-template<class T>
-inline Foam::label Foam::operator-
-(
-    const typename UPtrList<T>::iterator& iter1,
-    const typename UPtrList<T>::iterator& iter2
-)
-{
-    return (iter1.ptr_ - iter2.ptr_)/sizeof(T*);
-}
 
 template<class T>
-inline T& Foam::UPtrList<T>::iterator::operator[](label n)
+inline Foam::label Foam::UPtrList<T>::iterator::operator-
+(
+    const typename UPtrList<T>::iterator& iter
+) const
+{
+    return (ptr_ - iter.ptr_);
+}
+
+
+template<class T>
+inline T& Foam::UPtrList<T>::iterator::operator[](const label n)
 {
     return *(*this + n);
 }
 
+
 template<class T>
 inline bool Foam::UPtrList<T>::iterator::operator<(const iterator& iter) const
 {
     return ptr_ < iter.ptr_;
 }
 
+
 template<class T>
 inline bool Foam::UPtrList<T>::iterator::operator>(const iterator& iter) const
 {
     return ptr_ > iter.ptr_;
 }
 
+
 template<class T>
 inline bool Foam::UPtrList<T>::iterator::operator<=(const iterator& iter) const
 {
     return ptr_ <= iter.ptr_;
 }
 
+
 template<class T>
 inline bool Foam::UPtrList<T>::iterator::operator>=(const iterator& iter) const
 {
     return ptr_ >= iter.ptr_;
 }
 
+
 template<class T>
 inline typename Foam::UPtrList<T>::iterator
 Foam::UPtrList<T>::begin()
@@ -291,6 +301,7 @@ Foam::UPtrList<T>::begin()
     return ptrs_.begin();
 }
 
+
 template<class T>
 inline typename Foam::UPtrList<T>::iterator
 Foam::UPtrList<T>::end()
@@ -360,7 +371,7 @@ Foam::UPtrList<T>::const_iterator::operator++()
 
 template<class T>
 inline typename Foam::UPtrList<T>::const_iterator
-Foam::UPtrList<T>::const_iterator::operator++(int)
+Foam::UPtrList<T>::const_iterator::operator++(const int)
 {
     const_iterator tmp = *this;
     ++ptr_;
@@ -379,7 +390,7 @@ Foam::UPtrList<T>::const_iterator::operator--()
 
 template<class T>
 inline typename Foam::UPtrList<T>::const_iterator
-Foam::UPtrList<T>::const_iterator::operator--(int)
+Foam::UPtrList<T>::const_iterator::operator--(const int)
 {
     const_iterator tmp = *this;
     --ptr_;
@@ -389,7 +400,7 @@ Foam::UPtrList<T>::const_iterator::operator--(int)
 
 template<class T>
 inline typename Foam::UPtrList<T>::const_iterator
-Foam::UPtrList<T>::const_iterator::operator+=(label n)
+Foam::UPtrList<T>::const_iterator::operator+=(const label n)
 {
     ptr_ += n;
     return *this;
@@ -398,25 +409,7 @@ Foam::UPtrList<T>::const_iterator::operator+=(label n)
 
 template<class T>
 inline typename Foam::UPtrList<T>::const_iterator
-Foam::operator+(const typename UPtrList<T>::const_iterator& iter, label n)
-{
-    typename UPtrList<T>::const_iterator tmp = iter;
-    return tmp += n;
-}
-
-
-template<class T>
-inline typename Foam::UPtrList<T>::const_iterator
-Foam::operator+(label n, const typename UPtrList<T>::const_iterator& iter)
-{
-    typename UPtrList<T>::const_iterator tmp = iter;
-    return tmp += n;
-}
-
-
-template<class T>
-inline typename Foam::UPtrList<T>::const_iterator
-Foam::UPtrList<T>::const_iterator::operator-=(label n)
+Foam::UPtrList<T>::const_iterator::operator-=(const label n)
 {
     ptr_ -= n;
     return *this;
@@ -425,26 +418,34 @@ Foam::UPtrList<T>::const_iterator::operator-=(label n)
 
 template<class T>
 inline typename Foam::UPtrList<T>::const_iterator
-Foam::operator-(const typename UPtrList<T>::const_iterator& iter, label n)
+Foam::UPtrList<T>::const_iterator::operator+(const label n) const
 {
-    typename UPtrList<T>::const_iterator tmp = iter;
+    typename UPtrList<T>::const_iterator tmp = *this;
+    return tmp += n;
+}
+
+
+template<class T>
+inline typename Foam::UPtrList<T>::const_iterator
+Foam::UPtrList<T>::const_iterator::operator-(const label n) const
+{
+    typename UPtrList<T>::const_iterator tmp = *this;
     return tmp -= n;
 }
 
 
 template<class T>
-inline Foam::label Foam::operator-
+inline Foam::label Foam::UPtrList<T>::const_iterator::operator-
 (
-    const typename UPtrList<T>::const_iterator& iter1,
-    const typename UPtrList<T>::const_iterator& iter2
-)
+    const typename UPtrList<T>::const_iterator& iter
+) const
 {
-    return (iter1.ptr_ - iter2.ptr_)/sizeof(T*);
+    return (ptr_ - iter.ptr_);
 }
 
 
 template<class T>
-inline const T& Foam::UPtrList<T>::const_iterator::operator[](label n)
+inline const T& Foam::UPtrList<T>::const_iterator::operator[](const label n)
 {
     return *(*this + n);
 }