Yes, in California
you are liable for Personal Property Tax on vessels, the rate dependant upon the County where the boat is kept. That rate has usually been a little over 1% of the County's assessed valuation of your boat (which means they may, and probably will, assess the boat for far more than what you paid for it). Many Counties in California will also charge you a Possesory Interest (Real Property) Tax on the space and physical improvments your boat "enjoys" in a marina. That rate is a little over 1% of the net valuation of land and improvements.
Since you indicate that your next boat will be a 50' cat: Chula Vista Marina at the far end of San Diego
Bay that you mentioned is one of the very, very few marinas
in Southern California that once in a while advertises an available side or end tie for a multihull
. Some can also be found in L.A. Harbor. Be aware that Southern California has never been multihull
friendly as far as slip availability is concerned. Waiting lists for multis have historically been years, rather than months long.