I'm getting my boat back together. (a 19 ft open bow) The battery sits at the back by the engine. I want to move it forward and on center and add an aux battey. I also want to install them in the bildge below the floor and put a hatch cover over them. They will be in boxes, strapped down. What I'm wondering is if there are any rules about where to install and venting. I know they give off hydrogen gas when charging and discharging but hydrogen is lighter than air and so will rise up out of the bildge. I guess I would need a vented hatch cover. Any one see a problem with my plan or know of rules about where they can be installed.