Blacketts????
What happened to "Rob Blackett" from Swallowdale?? The Amazons' dad is only mentioned about 3 times in the whole series. He's dead, I know that, but did AR ever want to explain that?
We conclude that Bob Blackett was dead from Nancy's comment on Kanchenjunga the he 'was father' and Captain Flint reassuring Mrs Blackett that Bob 'would have' been happy with the Amazons the way they were.
I don't think AR is on record as ever having made any comments about Bob or when or how he died.
It is common in children's books for at least one parent to be dead or absent for some other reason, like being in the Navy. It helps the author arrange for children to have adventures without parents present (a perenial problem for children's authors).
Given the date of S & A, a dead father is a very realistic scenario. He could have died in WW1 or the 'flu epidemic immediately after it.
AR's own father died while he was still a boy. His child characters, especially the boys, who have live fathers seem to hold them in high esteem.

