Bunk Twin Captains Bed.
This would work like a railing on an upper deck, to keep the captain being thrown out of bed by a sudden throw of the ship. You do not have to make a tall lip, or even run the entire length of the bed. Allowing the middle of the side lower for easy entry and exit.

Cherry Twin Captains Bed

Finished Twin Captains Bed

Navy Blue Twin Captains Bed

Solid Pine Twin Captains Bed

Tucson Twin Captains Bed

Twin Captains Bed Dimensions

Twin Captains Bed With 6 Drawer Storage

Twin Captains Bed With Storage