Oldest Piece of Marine Ironwork Anywhere?

The museum has in its collection a ship’s rudder which was repurposed for use as an engineering anchor plate to secure one of the chains on the Gattonside pedestrian bridge near Melrose. The bridge was opened in 1826 and the rudder dates from that time.
The museum has discovered that this rudder, made of malleable iron, is a very early example of marine ironwork and perhaps the oldest known surviving piece of marine ironwork anywhere.