My 9 year old daughter Sarah sailed a complete schedule last season with me and even did the H16 North Americans.
She skippered in the Div.16 youth championship over the summer. She finished 2 races in the parent crewing division and won a race in 10-12mph. As Mary said I held onto the main sheet (calling UP,UP,UP a lot) while she drove and did the tacks and jibes. If anyone wants to say the H16 is not an exciting boat I would suggest crewing for a youth. Make sure they are warm and happy.