I dont think they are opposed to families...just liveaboard ones
Maybe they dont want what could be a proliferation of run down houseboats with lots of teenage kids etc. Kind of like a Trailer Park on the water . Not saying this is you, but look at the possibilities here.
Wow. The attitude you've just described is exactly
what liveaboards battle from the less knowledgeable outside world. Stereotyping looks ugly no matter who is painted, doesn't it?
We have weekenders at our marina who maintain their boats meticulously ... and those who show up every Friday evening to get drunk with their friends, and stay that way until Sunday afternoon and never leave the dock. We have liveaboards who are one step above being on the street ... and others who get up every weekday to drive to high-level professional jobs. There are boats that are never visited at all, just rotting in their slips.
A responsible marina will look not at how many nights you spend on your boat, but at how you maintain it and what the "boat" is. Many marinas here don't allow houseboats. Some mandate that you move the boat under its own power - i.e., get away from the dock - at least once every x months. Define the problem that you're really worried about, whether it's unseaworthy boats, unsuitable behavior, pollution, and mandate that. Much more effective than the blanket stereotypes.
Julienne - Speaking of stereotyping, I've also read that some marinas in Calif. won't allow living aboard boats less than 35 feet because they've determined that anything else doesn't have enough space. Weird.