You can get a pretty good feel for a Yacht Club's orientation by taking a look at the Club Calandar and reading through a few of their monthly magazines, which most clubs post on their web sites. For the sake of the exercise I looked at a few of Channel Islands monthlys (see Channel Island Yacht Club - Currents, The CIYC Newsletter
) and did not see a lot having to do with kids. On the other hand, at present the 3 senior officers of the Club are women which, in some cases, indicates a Club with some family orientation.
Having been a member of 3 different Clubs, they definately have different orientations. For example, the Richmond Yacht Club (SF Bay) and Alamitos Bay YC (Long Beach) are decidedly race oriented and both have excellant programs for children. By comparison, other Clubs have few if any programs for kids and are essentially Epicurian Societies albeit with marinas and a boating contingent. Clubs like this typically sport Tennis Courts, Pools, and large dining rooms with lots of "Dinner Events".
Within Clubs you may also find factions--Sailors vs Power Boaters vs the Epicurian Set that are only interested in cheap food and drink (and many of whom think that the marinas should subsidize their consumption habits). To get a sense of that, walk the docks; and, see how many members are boat owners verses non-boat owners.
When you do find a Club you think you might be interested in, call the Comodore and tell him/her you might have an interest in joining and see what the response is. Some Clubs will welcome you and have one of their members host you for visits to the facilities, drinks and dinner, and to meet other members. Others will not be so welcoming. Those that are not may or may not be Clubs you'd want to join anyway.
We have been members of one or another yacht club, or sometinmes two, for well over 35 years and generally have found it worth while, particularly when we travel aboard the boat as the "reciprocals" can be very nice and can save one a good deal of money on marinas etc. Having spent a lot of time kicking around sailing clubs as a child, they can also be very good for kids--if you're in the right Club.