Re: What kind of weapon to keep aboard my new dinghy?
I'd keep a wooden boat paddle in the dingy anyways but yes that's just me. A boat paddle could be just as lethal as a pool cue, and those things break skulls pretty well.
I wouldn't recommend traveling through Cali with a gun if you're not from Cali. The laws there are notoriously anti gun which is why I don't live there any more. Plus transporting a firearm across any border is bound to be a PITA. That's only if you declare it though, but gun running is a serious crime.
That said if I could take any 2 things aboard a boat, they would undoubtedly be an AR-10 or AK-47 and whatever pistol you feel comfortable with. I wouldn't take an AR-15 because the small 5.56 round is great for pounding flesh but poor against other things. 7.62 in full metal jacket with a steel core will seriously ruin peoples days, and give you some ranged defense- IE it will punch nice big holes in fiberglass and thin aluminum, maybe mess up an outboard motor if you're being pursued. That may only be realistic in Somalia though.
Handguns are an intensely personal choice. If it interests you, go to a gun store (NOT a big outlet unless its Cabelas) and hold every gun in the display case. One will speak to you.
That said, in Cali, I would just as soon have a hunting or dive knife and avoid the potential legal issues.
One other thing you could do is "disguise" your boat if you are going to be in rough areas for a period of time. A buddy and I were discussing this the other day and although we have done this with cars we haven't with boats. There's a wonderful material called Plastidip you can get at home depot that is a spray on latex covering in a certain color. The beauty if it is it forms a barrier and adds color but peels directly off a surface when you want it too. You could use some grey plastidip to make your hull look old and worn, and then some dark red plastidip to sumulate extensive rust stains. Won't fool a seasoned yachtsman but should be enough to make a casual criminal think that your boat and its contents are nothing of value. Then when you get to a safe area, an hour with a scrub brush and viola your old boat would be there underneath.