My understanding on spikes is that from 1700`s - spikes were used and recently I found a vessel that is dated 1940`s that also has sheating and spikes small copper ones the larger copper spikes Ive found on older vessels but nothing before 1700 I may be wrong but in the back of my mind Bob Marx has a book on this ( Treasure hunting )
Not sure of exact title -
Sorry if its no help.
James