[Michael.SF.]

She has been sailing since she was 13 years old and her older brother before then. It is highly unlikely that the family have sponsors back then.

Sailing is an expensive hobby.

They may not be independently wealthy, but they are not "poor".

[jimbo123]

Flashback:

Zac Sunderland sailing speedily along as parents sink deeper into debt

http://latimesblogs.latimes.com/outposts/2009/04/zac-sunderland-sailing-speedily-along-as-parents-sink-further-into-debt.html