Who would have thought that a water bottle could save your life while out at sea? An expert has revealed a crucial safety check that every cruise passenger should take as soon as they enter their cabin, which is placing a water bottle on the floor. This simple action can serve as an early warning system for potential dangers such as smoke, flooding, or ship instability.

Travel expert and CEO and Founder of CME Vacations, Dr. Steve Burgess, said: "Most passengers have no idea there's a simple five-second check they should perform the moment they enter their cruise cabin. Placing a water bottle on your cabin floor isn't a hydration reminder—it could literally save your life.

"It serves as an early warning system that could give you precious minutes to react during an emergency."

According to the expert, placing a water bottle on the floor near your bed can help alert you to several potential hazards before the official alarms are triggered.

Dr. Burgess added: "The water in your bottle will react to ship movements that you might not consciously register, especially when you're sleeping. 

"If you wake up and see the water sloshing unusually, it might be worth investigating further or alerting crew members."

The travel expert stated that if you observe ripples in your water bottle while the sea seems calm, it could be a sign of unusual vibrations or tilting of the ship which could indicate potential mechanical issues or problems with the ship’s navigation.

Although smoke rises, it can also seep under doors before reaching the ceiling-mounted smoke detectors, meaning that the water bottle placed on the floor could show condensation changes if smoke is starting to enter the cabin and serve as an early fire detector. 

The same goes for water. The water bottle can immediately tell you water is beginning to enter, whether this is due to a plumbing issue or another, more rare problem like a hull breach. 

Dr. Burgess said: "The water bottle trick is something I teach all our physician attendees. It costs nothing, takes seconds to implement, and could provide the early warning that makes all the difference in an emergency.

"What makes this tip so valuable is that it works while you sleep. Most emergencies at sea happen overnight when passengers are least alert and most vulnerable. Having this passive monitoring system in place gives you peace of mind and potentially crucial extra minutes to respond appropriately.

"While cruise ships today are incredibly safe, and serious incidents are rare, being prepared is something we emphasise in medicine—and it applies equally to travel. This simple habit has become second nature for experienced cruisers, but it's almost never mentioned in the safety briefings."