You are likely to be nailed for firearms violation if you are caught with one unless it is constructed with CA particulars in mind.
You won't be invited on many boats (mine included). Reason? Too much crap for me to deal with. And I go diving to enjoy the peace/serenity and may be dinner. Powerheads going off would not contribute to what I seek.
You will help hasten closures in CA. Read: Federal Register / Vol. 75, No. 33 page 7362
http://graysreef.noaa.gov/management...fr_75_7361.pdf