Martin: You are correct. I meant to say "Some" of the New Course and all of the Jubilee were under water. Blame old age and a late night!
I took a large scale copy of the 1821 chart and superimposed a recent google earth photo. The shoreline in 1821 follows the path between the New and the Jubilee almost exactly.
What I am unsure of is the extent of the 1893 Bruce Embankment land reclamation. Was it mainly around the first fairway? Regardless, there was much reclamation before the 1893 embankment. David Balfour in 1887 wrote that "there was a serious hazard made by the sea (on the last hole) which came up to the steps of the present clubhouse.... But the links have now been made much wider by the rubbish from the town having reclaimed a large portion from the sea."
Indeed, the construction of the present 1st green of TOC in 1870 was made possible by the previous reclamation efforts of Playfair and Bruce senior.
In 1894, a year after the "construction" of the embankment, the R&A was considering the construction of the New course, but was concerned because the new course would take up all the land between TOC and the sea, leaving no room for the public to exercise their rights to walking there.
Which is confusing to me, as the land for the Jubilee had to come there at sometime.
But when?