“Use these to leave messages for the room stewards sun as requests for ice, extra pillows, etc,” he wrote.
Ear plugs are also a good idea, especially for those holidaymakers who struggle to nod off.
“For light sleepers, I would encourage taking along some ear plugs,” Better advised.
“Ships will make a bit more noise than your typical house like creaking, cabin neighbours, people may waking their way back to their cabins in the middle of the night etc.”
source: express.co.uk