We co own a 58’ boat which has a fixed 4’ bed with an extra ‘swab’ which can be inserted on the inside to increase the width. Additional we have a sofa bed(extends to 4’) and the dinette area also make a double bed. Technically it is a six berthboat and we use it for two adults plus a dog only . Having slept separately for the period of our ownership we are now tackling the fixed double berth plus swab to widen. The inside person is not very comfortable owing to the gap between the swab and the mattress what do other folk do?