diff --git a/simgear/structure/SGSharedPtr.hxx b/simgear/structure/SGSharedPtr.hxx
index b99a6a8f..a494937b 100644
--- a/simgear/structure/SGSharedPtr.hxx
+++ b/simgear/structure/SGSharedPtr.hxx
@@ -98,6 +98,8 @@ public:
 private:
   void assign(T* p)
   { get(p); put(); _ptr = p; }
+  void assignNonRef(T* p)
+  { put(); _ptr = p; }
 
   void get(const T* p) const
   { T::get(p); }
diff --git a/simgear/structure/SGWeakPtr.hxx b/simgear/structure/SGWeakPtr.hxx
index c84ae371..78cfab4a 100644
--- a/simgear/structure/SGWeakPtr.hxx
+++ b/simgear/structure/SGWeakPtr.hxx
@@ -27,6 +27,8 @@ public:
   { }
   SGWeakPtr(const SGWeakPtr& p) : mWeakData(p.mWeakData)
   { }
+  SGWeakPtr(T* ptr)
+  { assign(ptr); }
   template<typename U>
   SGWeakPtr(const SGSharedPtr<U>& p)
   { SGSharedPtr<T> sharedPtr = p; assign(sharedPtr.get()); }