Gareth,
This really gets us back to who is the target market for the boat.
If it is children 7 to 12 yrs that weigh less than 60kg then having the boat invert could be a good thing.
An inverted boat does not drift anywhere near as quick as a boat on its side. They could catch up with an inverted boat but never catch a boat on its side.
Very young children are unlikely to be able to right the boat and the inverted boat provides a safe area between the hulls where the children can wait in for assistance.

Regards,
Phill

I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!