AC Grounding

[markmcb]

Hello, I am a new member and new to sailing. What a wonderful feeling.
I have just acquired an old Cal 28 and now have a long list of projects.
At the top of the list, is installing an AC and DC electrical system. The boat came with 2 batteries (with 2 busses) connected to a DC panel, and a 30 amp shore plug that is not wired. My plan is to connect the shore plug to an AC panel with a 2-pole 30 amp breaker and 3 15 amp breakers. I will then connect a battery charger and AC outlets to this. My problem is where to ground these systems. In most places, I have read to connect the ground to the engine...but I have no engine.I do have what seems to be a through hull bolt that has a ground cable attached to it from the head's seacock. I have read not to ground to seacocks, as they may blow out and sink the boat. I suppose the DC system can just be grounded to the negative post of the battery, but what of the AC side?
I appreciate any thoughts....Thanx