It is also worthwhile to look at the Clive Carey Collection of sea shanties, collected by Carey in South Australia in 1924/25, from a George Pattison and a Malcolm Forbes. You will find them at Fahey's web site here:

http://warrenfahey.com/ccarey-s1.htm

and here:

http://warrenfahey.com/ccarey-mf1.htm

Fahey says that Forbes was an old man when Carey recorded his songs. Carey did not give any information that would help us determine how far back into the 1800's these songs go, but at least they are placed in South Australia in that century and from the age of at least one of the informants would seem to have been around for awhile.