Since the warm weather is still a bit away, you have the time to make "baby steps" in helping your child want to participate in your pass time. Does he have a toy sailboat? You could start by making it part of tub time and then allow him to play freely (but supervised, of course) in the sink full of water. Then in a wading pool. Most toy sailboats are hard to keep upright and he will be challenged by this which is an opportunity to tell him about the mechanics of the boat - something most boys are drawn to. Perhaps check out a cartoon containing sailing in it and then more of a "real" children's film from the library. The next step would be to get him near your boat, and then later on the boat while it is not sailing (maybe for the pre-season clean-up?), and then later still for short excursions. If he is still not interested in joining you, perhaps there is a relative or friend he could stay with when you go out on the boat. When you return, make sure you all tell him how much fun you had and all of the things that you saw. This will be especially effective if coming from his sibling. Not to guilt him, but rather to inform him and to peak his interest). The next time you go out he might be more likely to want to come along. Even if he doesn't you aren't going to lose out since you will be providing an opportunity for special one-on-one time with the person who babysits him. I grew up on the water and it is something special. I, too, hope our children enjoy our passion. Good luck!