How Long Can You Survive In Open Water?

People stranded on a boat or life raft can survive several days longer than the poor souls stuck in the water with just a life jacket.

The supplies you have with you also determine how long you can hold out before being rescued. The human body can survive for an impressive two to three months without food, but it will not last longer than a week without drinking water.

Being stranded at sea is just about everyone’s worst nightmare. Even the thought of being alone on the water with no land in sight sends shivers down my spine. Nevertheless, you may be surprised how long some people have survived while being adrift at sea.

Though it is a grim and terrifying experience, some survivors have gone hundreds of days in open water, while others have died after just a few hours.

Understanding the Risks

When considering survival in open water, it’s crucial to understand the direct impact the environment will have on your body. Variables such as water temperature can lead to life-threatening conditions like hypothermia or dehydration. Below, you’ll find focused explanations on the major risks and how they affect your ability to survive in the ocean.

Hypothermia and Heat Loss

If you find yourself in open water, the cold temperatures can rapidly decrease your body temperature, leading to hypothermia.

This condition occurs when your body loses heat faster than it can produce it, causing a dangerously low body temperature.

Symptoms to watch for include excessive shivering, slurred speech, and drowsiness. Survival time can be limited as hypothermia sets in quickly, especially in water below 70°F (21°C).

Everyone can take inspiration from Kay Longstaff’s story. After falling off the back of a cruise ship in Croatia while on holiday, she had to survive for ten hours before being rescued.

The British women did not have a life jacket on but managed to stay afloat, thanks to the calm and flat conditions of the Mediterranean Sea. 

Fortunately for her, the Mediterranean Sea has warm water. She fell into 80°F water, which is around the temperature of a swimming pool.

At that temperature, it takes longer for the human body to develop life-threatening conditions like hypothermia.  

Dehydration and Electrolyte Imbalance

Even surrounded by water, you’re at risk of dehydration since seawater is not suitable for drinking.

You can live without water for only a few days, and being in the sun increases your need for hydration.

The loss of electrolytes, essential for muscle and nerve function, can result from dehydration and drinking seawater due to its high salt content. Carry fresh drinking water to maintain hydration levels and prevent electrolyte imbalance when in open water.

Drowning and Panic Response

Drowning is a significant risk during ocean survival, often exacerbated by a panic response.

When fleeing danger or confronting unexpected situations in open water, your body’s instinct may be to gasp and hyperventilate, increasing the risk of inhaling water.

It’s vital to control your breath and stay calm. Techniques like the blow method, exhaling against pursed lips to create back pressure, can be crucial.

This technique helps maintain airway pressure and prevents water from entering your mouth and nose.

Immediate Survival Strategies

When you find yourself in open water, your immediate goal is to maintain buoyancy, conserve energy, and attract the attention of rescuers. Applying these strategies can drastically increase your survival odds.

Floating and Energy Conservation

Conserving energy is crucial to prolonging your survival in open water. You minimize exhaustion by floating on your back or using the dead man’s float. Keep your arms and legs still unless necessary to adjust for waves, and use slow, deliberate movements when you do.

Improvising Flotation Devices

If you don’t have a flotation device, you can use your clothes to create makeshift ones. Tying the ends of pants legs into knots and filling the pockets with air can provide a temporary lift.

Hold the waistband underwater after filling the legs with air, which will trap the air to create buoyancy. Similarly, a shirt can be used as a crude life jacket by buttoning it up, pulling it over the legs, and filling it with air.

Signaling for Rescue

For signaling, brightly colored clothes, reflective materials, or signaling mirrors can increase your visibility.

Flares are ideal but only if included in your survival equipment. If you have a whistle or a reflective surface, use it intermittently to catch the light and sound attention.

Remember to reserve your energy and use such devices when a plane or ship is in sight to maximize the chance of being seen.

Long-Term Survival Considerations

In open water, your longevity hinges on securing essential resources and shielding yourself from harsh environmental factors. With strategic methods, you can increase your chances of prolonged survival.

Finding Food and Water

Your first priority should be water, as you can only survive a few days without it due to dehydration.

Collecting rainwater or using a makeshift solar still can provide you with potable water.

Fishing is your most reliable option for food, provided you can improvise fishing equipment.

A fishing kit may include hooks fashioned from pieces of metal or bone and shoelaces or strands from clothing serving as line. You can increase your chances of catching fish by understanding their routines and remaining patient.

  • Water Collection
    • Rainwater: Use any available containers to catch rain.
    • Solar stills: Employ plastic sheeting to create condensation traps.
  • Fishing Techniques
    • Improvised gear: Transform debris or items like safety pins into hooks.
    • Make use of natural resources: Insects, small fish, or pieces of meat can work as bait.

Protecting Against the Elements

Maintaining body temperature is crucial for survival. Direct exposure to the sun can lead to sunburn or heatstroke, so creating or finding shelter is a must.

Use any available materials: Tarps, debris, and even dense seaweed can help you avoid overexposure to the elements.

Your clothing will be your first defense against the environment; keep as much of your skin covered as possible to protect against the sun and conserve body heat.

  • Shelter Building
    • Improvise with materials at hand: Construct a canopy with a sheet or part of a sail.
    • Floatation devices: Utilize life jackets or other buoyant items to elevate parts of the body out of water when resting.
  • Clothing Optimization
    • Cover up: Preserve clothing to cover skin against harmful UV rays.
    • Innovation: Repurpose materials to add layers or additional protection.

Survival Equipment and Techniques

Though there are many types of boats that sailors can embark on, whether a yacht, sailboat, cruise ship, oil tanker, etc., sailors should generally have the following safety and sea survival equipment on board their boat.

  • First aid kit to treat injuries
  • Life Jackets/life vests to stay afloat in case of emergency
  • VHF radio to call for rescue
  • Satellite phone to call for rescue
  • Knife to cut entangled ropes
  • Tool kit for repairs
  • Signaling devices to call for help
  • Well-equipped lifeboat/raft
  • Paddles and oars if there is an issue with the engine
  • Buckets or other bailing devices to dewater the vessel
  • Powerful flashlights

Life-Saving Gear

  • Life Vest/Jacket: Ensure your life vest or jacket is U.S. Coast Guard-approved for maximum safety; it is your first line of defense against drowning.
  • Life Raft: A sturdy life raft is indispensable. It should be equipped with a canopy for shelter and be bright-colored for visibility.
  • Flares: Always have flares on hand to signal for help; they’re vital for being spotted by rescuers.
Life JacketKeeps you afloat without expending energy
Life RaftProvides shelter and a platform for signaling
FlaresUsed to signal rescuers

Effective Use of Survival Kits

Hopefully, it never comes to this, but if a sailor and their crew are forced to abandon ship, they must take a grab bag, also known as a ditch or panic bag, with them.

A well-equipped grab bag will not only increase your chances of survival following the abandonment of the ship, but the equipment stored inside can dramatically increase your chances of being rescued.

A good grab bag must be waterproof and made from durable materials. Its location on the boat should also be known to all the crew members. Here is what the ideal bag should contain:

  • Drinking water. Drinking water is hard to come by on the open ocean, so it is necessary to have as much water as possible in the emergency bag.
  • Water maker. A water maker can convert seawater to drinking water.
  • Non-perishable food. Food is also hard to come by in the open water. A fair amount of rations should be packed, especially when trips are far from the coast.
  • First aid kit. Medications and bandages to treat injuries.
  • VHF radio. Sailors adrift can call for rescue using a VHF radio. Some spare batteries should also be packed in the bag. Some VHF radios have an integrated GPS that can give rescuers the survivor’s location.
  • Signaling devices. Signaling devices like flares and mirrors can help draw attention from potential rescuers.
  • Fishing kits. A fishing rod will come in handy once survivors have run out of food.
  • Flashlights. It gets pretty dark at night on the water, as there is no light population.

Practical Skills for Open Water Survival

You must be versed in practical skills such as navigating with the sun or stars, fishing without conventional gear, and knowing the H.E.L.P. position to maintain body heat.

  • Navigation: Use celestial cues or wave patterns for navigation if you’re adrift without a compass.
  • Knot-tying: Essential for securing gear or repairing your raft. Knowledge of various knots can be a lifesaver.
NavigationDetermines direction without instruments
Knot-tyingSecures equipment, could aid in repairs

Psychological Aspects of Ocean Survival

Surviving in the ocean demands as much mental tenacity as it does physical strength. Your psychological readiness can make the difference between life and death. Stay focused, stay calm, and keep your morale high.

Combatting Fear and Maintaining Morale

Fear is an immediate response when you find yourself in the middle of the ocean. It’s natural to feel scared, but allowing panic to take over can be detrimental. Here’s how to keep it at bay:

  • Take deep breaths: This simple action can help regulate your blood pressure and reduce panic.
  • Set achievable goals: Focus on small, manageable tasks to maintain a sense of control.

Stress Management and Mental Resilience

A science writer might tell you that survival stories often highlight the significance of mental resilience. To manage stress you should:

  • Monitor your mood: Keep a mental check on any negative thoughts and actively work on maintaining a positive outlook.
  • Stay mentally active: Engage in mental exercises or go over survival strategies to keep your mind sharp.

Frequently Asked

What’s The Longest Someone Has Survived Lost At Sea? 

As of 2022, Japanese sailors Oguri Jukichi and Otokichi hold the record for surviving the longest time adrift at sea. The two sailors were stranded for four hundred and eighty-four days from 1813 to 1814.

Jukichi’s ship mast was destroyed in a storm on a voyage in the Pacific. Ultimately, the ship drifted over five thousand miles to reach California. Jukichi and Otokichi were the only survivors of the crew.

People who hold undesired records for being stranded at sea for the longest time, like Salvador Alvarenga and Oguri Jukichi, were adrift on boats. Had they been on a raft or other floatation devices, it is unlikely that these survivors would have made it home.

Having some cover on your vessel is crucial to your survival in these scenarios. It will protect you from the harsh and unforgiving sun and keep you somewhat warm at night. It will also come in handy when harvesting rainwater. 

How Do People Survive Being Left In The Open Ocean? 

There is no shortage of incredible survival stories in the open ocean. Many of the survivors have, one way or another, managed to stay fed and hydrated, which are the two most critical things. 

Some people are more fortunate than others and end up on a lifeboat or raft that is well-equipped to extend their survival. Some survivors have depended on drinking rainwater, urine, and even animal blood to stay hydrated and alive.

What Is The First Rule Of Ocean Survival?

Water is life. Without drinking water, you will be lucky to survive longer than a week. Finding and securing drinking water is the most important thing you can do in the first moments of being stranded.

In addition, not drinking seawater while you are adrift at sea is just about as important. The temptation to drink seawater is great, especially if dehydrated. But doins so only increases dehydration.

I’m the founder and chief editor here at Sailing Savvy. I spent a decade working as a professional mariner and currently, I mix those experiences with digital publishing. Welcome, and I hope that we can be the hub you need for safe passage.