diff --git a/applications/test/PtrList/Test-PtrList.C b/applications/test/PtrList/Test-PtrList.C
index a8cf8686af..d35e321d71 100644
--- a/applications/test/PtrList/Test-PtrList.C
+++ b/applications/test/PtrList/Test-PtrList.C
@@ -403,7 +403,7 @@ int main(int argc, char *argv[])
         << "list2: " << list2 << endl;
 
     Info<< "indirectly delete some items via setSize :" << endl;
-    list1.setSize(4);
+    list1.resize(4);
 
     Info<< "list1: " << list1 << endl;
 
@@ -446,8 +446,48 @@ int main(int argc, char *argv[])
             << "addresses:" << nl;
         printAddr(Info, list1b);
         printAddr(Info, list1c);
+
+
+        PtrDynList<Scalar> dynlist1d;
+        PtrDynList<Scalar, 5> dynlist1b(list1b.clone());
+        PtrDynList<Scalar, 8> dynlist1c(list1b.clone());
+
+        Info<< "append:" << nl;
+        Info<< "in: " << dynlist1b << nl
+            << "in: " << dynlist1c << nl
+            << "addresses:" << nl;
+        printAddr(Info, dynlist1b);
+        printAddr(Info, dynlist1c);
+
+        dynlist1d.append(std::move(dynlist1b));
+        dynlist1d.append(std::move(dynlist1c));
+
+        Info<< "result:" << nl;
+        print(Info, dynlist1d);
+
+        Info<< "addresses:" << nl;
+        printAddr(Info, dynlist1d);
+
+        PtrList<Scalar> list1d;
+
+        Info<< "append:" << nl;
+        Info<< "in: " << list1b << nl
+            << "in: " << list1c << nl
+            << "addresses:" << nl;
+        printAddr(Info, list1b);
+        printAddr(Info, list1c);
+
+        list1d.append(std::move(list1b));
+        list1d.append(std::move(list1c));
+
+        Info<< "result:" << nl;
+        print(Info, list1d);
+
+        Info<< "addresses:" << nl;
+        printAddr(Info, list1d);
     }
 
+
     PtrList<Scalar> list3(std::move(list1));
     Info<< "Move constructed" << endl;
 
@@ -473,6 +513,8 @@ int main(int argc, char *argv[])
     Info<< "UPtrList from PtrList" << nl;
 
     UPtrList<Scalar> ulist1(list3);
+    UPtrList<Scalar> ulist1b(list3);
+    UPtrList<Scalar> ulist1c(list3);
 
     Info<< "ulist1: " << ulist1 << nl;
     Info<< "PtrList addresses:";
@@ -481,6 +523,12 @@ int main(int argc, char *argv[])
     printAddr(Info, ulist1);
     Info<< nl;
 
+    ulist1c.append(std::move(ulist1b));
+
+    Info<< "UPtrList append/append:";
+    printAddr(Info, ulist1c);
+    Info<< nl;
+
     {
         Info<< "UPtrList(const UPtrList&)" << nl;
 
diff --git a/src/OpenFOAM/containers/PtrLists/PtrDynList/PtrDynList.H b/src/OpenFOAM/containers/PtrLists/PtrDynList/PtrDynList.H
index 5311f33333..955766be26 100644
--- a/src/OpenFOAM/containers/PtrLists/PtrDynList/PtrDynList.H
+++ b/src/OpenFOAM/containers/PtrLists/PtrDynList/PtrDynList.H
@@ -87,6 +87,9 @@ public:
         //- Move construct
         inline PtrDynList(PtrDynList<T, SizeMin>&& list);
 
+        //- Move construct from PtrList
+        inline PtrDynList(PtrList<T>&& list);
+
         //- Take ownership of pointers in the list, set old pointers to null.
         inline explicit PtrDynList(UList<T*>& list);
 
diff --git a/src/OpenFOAM/containers/PtrLists/PtrDynList/PtrDynListI.H b/src/OpenFOAM/containers/PtrLists/PtrDynList/PtrDynListI.H
index cfb7f06d13..e5fc02a675 100644
--- a/src/OpenFOAM/containers/PtrLists/PtrDynList/PtrDynListI.H
+++ b/src/OpenFOAM/containers/PtrLists/PtrDynList/PtrDynListI.H
@@ -73,6 +73,17 @@ inline Foam::PtrDynList<T, SizeMin>::PtrDynList
 }
 
 
+template<class T, int SizeMin>
+inline Foam::PtrDynList<T, SizeMin>::PtrDynList
+(
+    PtrList<T>&& list
+)
+:
+    PtrList<T>(std::move(list)),
+    capacity_(PtrList<T>::size())
+{}
+
+
 template<class T, int SizeMin>
 inline Foam::PtrDynList<T, SizeMin>::PtrDynList(UList<T*>& list)
 :
@@ -195,8 +206,11 @@ inline void Foam::PtrDynList<T, SizeMin>::swap
     PtrDynList<T, AnySizeMin>& other
 )
 {
-    // Cannot compare 'this' for different types, so use cdata()
-    if (this->cdata() == other.cdata())
+    if
+    (
+        static_cast<const PtrList<T>*>(this)
+     == static_cast<const PtrList<T>*>(&other)
+    )
     {
         return;  // Self-swap is a no-op
     }
@@ -269,9 +283,9 @@ inline void Foam::PtrDynList<T, SizeMin>::append(PtrList<T>&& other)
 
     resize(idx + len);
 
-    for (label i=0; i < len; ++i)
+    for (label i = 0; i < len; ++i)
     {
-        set(idx + i, other.release(i));  // moves pointer
+        set(idx + i, other.release(i));  // Take pointer ownership
     }
 
     other.clear();
@@ -285,14 +299,25 @@ inline void Foam::PtrDynList<T, SizeMin>::append
     PtrDynList<T, AnySizeMin>&& other
 )
 {
+    if
+    (
+        static_cast<const PtrList<T>*>(this)
+     == static_cast<const PtrList<T>*>(&other)
+    )
+    {
+        FatalErrorInFunction
+            << "Attempted append to self"
+            << abort(FatalError);
+    }
+
     const label idx = this->size();
     const label len = other.size();
 
     resize(idx + len);
 
-    for (label i=0; i < len; ++i)
+    for (label i = 0; i < len; ++i)
     {
-        set(idx + i, other.release(i));  // moves pointer
+        set(idx + i, other.release(i));  // Take pointer ownership
     }
 
     other.clearStorage();  // Ensure capacity=0
@@ -451,8 +476,11 @@ inline void Foam::PtrDynList<T, SizeMin>::operator=
     const PtrDynList<T, AnySizeMin>& list
 )
 {
-    // Cannot compare 'this' for different types, so use cdata()
-    if (this->cdata() == list.cdata())
+    if
+    (
+        static_cast<const PtrList<T>*>(this)
+     == static_cast<const PtrList<T>*>(&list)
+    )
     {
         return;  // Self-assignment is a no-op
     }
@@ -503,8 +531,11 @@ inline void Foam::PtrDynList<T, SizeMin>::operator=
     PtrDynList<T, AnySizeMin>&& list
 )
 {
-    // Cannot compare 'this' for different types, so use cdata()
-    if (this->cdata() == list.cdata())
+    if
+    (
+        static_cast<const PtrList<T>*>(this)
+     == static_cast<const PtrList<T>*>(&list)
+    )
     {
         return;  // Self-assignment is a no-op
     }
diff --git a/src/OpenFOAM/containers/PtrLists/PtrList/PtrList.H b/src/OpenFOAM/containers/PtrLists/PtrList/PtrList.H
index a1814440b3..ec59fb7a2b 100644
--- a/src/OpenFOAM/containers/PtrLists/PtrList/PtrList.H
+++ b/src/OpenFOAM/containers/PtrLists/PtrList/PtrList.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2018-2020 OpenCFD Ltd.
+    Copyright (C) 2018-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -173,6 +173,9 @@ public:
         //- Move or clone append a tmp to the end of the list
         inline void append(const tmp<T>& ptr);
 
+        //- Move append another list to the end of this list.
+        inline void append(PtrList<T>&& other);
+
         //- Construct and set an element
         template<class... Args>
         inline autoPtr<T> emplace(const label i, Args&&... args);
diff --git a/src/OpenFOAM/containers/PtrLists/PtrList/PtrListI.H b/src/OpenFOAM/containers/PtrLists/PtrList/PtrListI.H
index 452bd85d2a..ce80607dc5 100644
--- a/src/OpenFOAM/containers/PtrLists/PtrList/PtrListI.H
+++ b/src/OpenFOAM/containers/PtrLists/PtrList/PtrListI.H
@@ -151,6 +151,30 @@ inline void Foam::PtrList<T>::append(const tmp<T>& ptr)
 }
 
 
+template<class T>
+inline void Foam::PtrList<T>::append(PtrList<T>&& other)
+{
+    if (this == &other)
+    {
+        FatalErrorInFunction
+            << "Attempted append to self"
+            << abort(FatalError);
+    }
+
+    const label idx = this->size();
+    const label len = other.size();
+
+    resize(idx + len);
+
+    for (label i = 0; i < len; ++i)
+    {
+        set(idx + i, other.release(i));  // Take pointer ownership
+    }
+
+    other.clear();
+}
+
+
 template<class T>
 template<class... Args>
 inline Foam::autoPtr<T> Foam::PtrList<T>::emplace
diff --git a/src/OpenFOAM/containers/PtrLists/UPtrList/UPtrList.H b/src/OpenFOAM/containers/PtrLists/UPtrList/UPtrList.H
index 4f88822e98..6caee41a85 100644
--- a/src/OpenFOAM/containers/PtrLists/UPtrList/UPtrList.H
+++ b/src/OpenFOAM/containers/PtrLists/UPtrList/UPtrList.H
@@ -268,6 +268,9 @@ public:
         //- Append an element to the end of the list
         inline void append(T* ptr);
 
+        //- Move append another list to the end of this list.
+        inline void append(UPtrList<T>&& other);
+
         //- Swap content
         inline void swap(UPtrList<T>& list);
 
diff --git a/src/OpenFOAM/containers/PtrLists/UPtrList/UPtrListI.H b/src/OpenFOAM/containers/PtrLists/UPtrList/UPtrListI.H
index 1716ddf253..b96f1371e9 100644
--- a/src/OpenFOAM/containers/PtrLists/UPtrList/UPtrListI.H
+++ b/src/OpenFOAM/containers/PtrLists/UPtrList/UPtrListI.H
@@ -93,7 +93,7 @@ inline Foam::UPtrList<T>::UPtrList(UList<T>& list)
 {
     const label len = ptrs_.size();
 
-    for (label i=0; i<len; ++i)
+    for (label i = 0; i < len; ++i)
     {
         ptrs_[i] = &(list[i]);
     }
@@ -196,9 +196,15 @@ inline void Foam::UPtrList<T>::resize(const label newLen)
 template<class T>
 inline void Foam::UPtrList<T>::append(T* ptr)
 {
-    const label idx = this->size();
-    ptrs_.resize(idx + 1);
-    ptrs_[idx] = ptr;
+    ptrs_.append(ptr);
+}
+
+
+template<class T>
+inline void Foam::UPtrList<T>::append(UPtrList<T>&& other)
+{
+    ptrs_.append(other.ptrs_);
+    other.ptrs_.clear();
 }