I take all but the youngest (just 1 y.o.) out whenever I go. The older boys (10, 8) like sailing but are more prone to seasickness so that puts a damper on things. That said, the 10 yo is getting a good handle on helming and we're working on sail trim. They both like doing maintenance tasks.
The girls (6,4,2) are my real hope as they are all water monkeys and really
like going out. They are the biggest drivers for taking longer trips.
I like the sailing dinghy idea- We have a dhow and I think next summer will be a good time to take the boys out on it with an eye on having them sail it themselves.