Samuel Sweeney

I am trying to find out more about SAMUEL SWEENEY - his life in Ireland and his famiily -  and would appreciate any help or suggestions!

He was born in Ireland (Buncrana, Donegal? ) in 1836, judging from the age on the passenger list (38) when he sailed for Australia in 1874.  However, his death certificate suggests he may have been born in 1831. His given age of 40 on his 1875 marriage certificate to Thirza Turner, supports the former date. Place of birth on the death certificate is given as Londonderry. However, the 1975 marriage certificate gives Buncrana, Donegal, as his place of birth.
Samuel's mother’s name on the records of the Townsville cemetery, where Samuel was buried in 1899, is Jane Watts.The name of his father on his marriage record Samuel Edward Sweeney, whose occupation was a clothier (maker of clothes). However, his occupation on his son’s 1875 marriage certificate is given as farmer. Other researchers give 1877 as the date of death for both Jane Watt and Samuel Edward Sweeney.  However, I could not find any definitive records confirming this, or indeed any details about these two people.
I also could not find any information about where Samuel Sweeney grew up, where he lived or whether he married. There is a record of Samuel Sweeney apprenticed on a ship called the Corfu, registered in Belfast. The record is dated 1851, and the age of the apprentice is 14.
The first confirmed record of Samuel Sweeney is his departure from England on the ship Derbyshire, on April 1 1874

Thanks