It's a shame your Dad is giving you problems. I'm sure its hard for people that don't go out in the water and have the experiences we do to relate to it. I know my Dad just looks and me and laughs when it's the middle of January, and I'm walking out with a surfboard under my arm. He's always the first to ask how it went though and seems pretty stoked to hear about it. He gets a kick out of hearing the stories of me getting worked. Try and sit him down, explain your side and listen to his as well. Maybe pop a surf movie in. My Dad's jaw dropped watching AI's part in high five, he let out a few "Holy s*%&'s!". Keep at it, he may come around.