Jaglady on Family Tree Circles

My GGFather was John Jacob Grot KOPP. He was born in Denmark in 1843.
He settled in South Australia about 1867. He was a Captain in the Merchant Marine, and later became a lighthouse keeper serving on most lighthouses around South Australia, including those on Kangaroo Island. He died in Adelaide 14 Nov 1924, & is buried at Brighton.

I have found that his father was Claus Honri Grot KOPP, as he is listed as a witness to JJKopp's 1st marriage.

That marriage was to Susannah Barbara SKELTON on board the hulk Hariul Hope at Glenelg in 1880. There were two children from this marriage:
1.Elzabeth Agnes KOPP b.Sept 29 1881.
2.John Edward Alexander KOPP b. Jan 6 1883.

His second marriage was to Jane Elizabeth ANGUS 21 Aug 1890.
Children from this marriage were:
1. Florence Amelia KOPP b.Aug 10 1891
2. Alexander KOPPP b. 1893
3. Irene KOPP b. 1894
4. Dorothy Edith KOPP b. 1898
5. Kathleen May KOPP b.1900 (My Grandmother)
6. Anne KOPP b.1901
7. Albert Edward KOPP b.1902.

I have hit the Brick Wall. Any info on KOPP or GROT KOPP from Denmark to Australia would be greatly appreciated.