Can you having a shotgun and pistol on boat in the bay?

If you're in the USA and on US Territorial waters, yes you can. However, if you are boarded by Law Enforcement, you must notify them of the weapons on board. I guarantee that they will secure the weapons from you. It's not a smart thing to carry for no reason. There's no reasonable explanation that you can give to them as to why you have to carry a concealed weapon.