Ramona's comment is interesting, why would anyone store a heavy lump - like a battery, chain, anchor or dive bottle - at the furthermost possible points, away from the center of a vessel, is beyond me.
I stored my dive bottle in the best spot I found on a 28 foot boat and it worked for me. (Yes, I know, work-safety people start salivating and having a fit now!

)
Just as the 120 feet anchor-chain weighing 300lb was stored close to the mast-base, not in the chain locker, the heavy dive-bottle was not far from it, either.
Storing four of the suckers below, close to the center would make perfect sense, I certainly would not store them on the stern even on a fifty footer.