We have had a little of that ourselves. But this summer was better, Artie got use to the idea he was on the boat for six weeks or more. He entertained us by putting on a puppet show through the front hatch. Dangled his legs from the front of the boat seeing on how wet he could get. He managed to catch his first fish very excited! Plus he did loads of drawing and listened to music and stories, when it was calm we swam around the boat he learnt to swim without ad this year, and learnt how to tie a bowline and a few others, which i was amazed at as he has only just learnt to tie his shoe laces. He did have his moments of being bored but they got less but he is only six a ten year old maybe harder.
Let us know if you think of any ideas and If I think of any ideas as well I let you know. Good luck and keep posting.
Amanda
Good luck

Maybe you can suggest that you go together to jump from some cliffs, fish crabs, maybe water skiing if the dinghy is fast enough, snorkeling, windsurfing. Keep the activities action packed. Keep the sailing distances short. Anyway, I think your problem is the same many of us have, probably a problem of our time.