With a fully upholstered top section, this Colonial teak Cabin Bed is a little different to others we have seen.
The top section is removable on this version whereas a standard cabin bed is not built to come apart. Added to this, it's common on others to have the back and sides caned to allow for easy circulation of air in a hot climate. This one only has the seat caned. A cabin bed would serve as both a bed and a settee and give you drawer space. As you provided your own furniture for your hired cabin on a long journey, it was important to be as practical with your limited space as possible. A cabin bed fulfilled these criteria.
Originally it would have had two sections to the front corners of the seat to prevent you falling out of bed in stormy seas. Typically these were made to either be removed or fall forward when you wanted to use the bed as a sofa. It is unusual to find a cabin bed still retaining these sections, with the vast majority removed when their purpose was no longer needed. Mid 19th Century.