Amps are a lot more important than voltage to crank a motor. For instance Two G31 in parallel To a 12v starter will be just as good as two G31 in series cranking a 24v starter. Where it makes a difference is voltage drop in the cables. On the MY, with Hatteras placing the batteries in the gen room resulting in longer run (especially with battery switches high up on the walls, at least on the early boats) the higher voltage is a plus.