I have a boat with bunk bed
sleeping. Also a staggered V-berth at the same heights. Note. Both suck.
The lower one is like sleeping 18 inches above the floor. I can't sit up in it without hitting my head
on the above bunk. Because it is in a step down are (galley and sleeping area + doors to the head
and stateroom) my view outside is level with the floor of the salon
. I don't know if I want to wake up looking at the floor of my home everyday.
The upper one requires the same device airports use when the boarding gateway is broken. A truck with a long ladder on the back. This bunk + intoxication = a fall in blackness @ 3am on the way to the head.
The forward has the same elevation challenges with the addition of being tapered aft to fore. And it's a little claustrophobic in there. And dark.
So I hope I have explained why this bunk arrangement was unpopular.