For some people sailing is not associated with pleasure but stress and anxiety or fear. Those associations can be tackled partly by organisation and partly by dealing with them as any other phobia. Hint would you expect rubbishing to overcome a fear of heights or flying?
As some have mentioned it is a good policy to give others hands on learning as an introduction. However it is difficult to do that when one of you has to focus on a child.
A child of that age is a major problem not just because it is the NO stage and the running away and crossing roads stage but also because of an inability to brace and the danger of being thrown around and impeding movement. One person I know installed a car seat in the cockpit. Another idea is to try to make as much of the time correspond with sleep time as possible. To keep the child below make a child space say in the quarterberth say decorated with stars, butterflies, fairies, or whatever the child is keen on with their input so they are happy to spend time there.
For all of you the associations should be fun relaxation and pleasure think food wine and laughter, not stress coercion and fear.