'The waters getting cold and the suns setting on what could be you're last night alive, the boat went under so fast you had barely enough time to don clothing. Now what do you do?'

Its a bad environment for survival, in fact being adrift at sea is possibly the most daunting of all survival situations. The sea is an inherently hostile environment due to a number of factors:

Oceanic Traits

Some areas of the worlds oceans, especially in the northern hemisphere can experience rough seas and weather the year round. Seas closer to the equator tend to be more forgiving with warmer waters and calmer seas, although seasonal storms such as monsoons, hurricanes and the like are occasionally present. The sun, although essential for life can be a double edged sword at sea, the suns rays can be inescapable on an exposed craft or driftwood. Added to this the reflective effects of a glass-like ocean and sun can take on a harsher more deadly effect.
The water temperature of the worlds oceans can range from a deadly -1 C to up 34 C with a fall in temperature at night-time. The temperature range can vary with the seasons but as a general rule the closer to the equator the warmer the ocean gets.

The Human Body

Jumping into the sea from a stricken ship or vessel may be the quickest way off it but this can be foolhardy as well. From a high platform or the upper levels of a cruise ship the impact on the water surface may be sufficient to knock you unconsious. Another factor is that without a survival suit there is a risk in cold water of gasping for air on impact and drowning, so ensure you take and hold a deep breath before jumping. Survivalwise the human body can only survive for a certain period of time in sea water before succumbing to exhaustion / unconsiousness and drowning.

Evolution has seen mankind evolve in a land-based environment and part of this has meant the human body operates at about 37 Celcius and will begin to loose body heat once immersed in anything below this temperature. Additionally treading water will accelerate the cooling effect further. A wetsuit can slow down this process and a drysuit reduces the 'chilling' effect even more. If there are several survivors good plan is to form a close circle to conserves body heat and can raise group spirits. This also makes it easier for search and rescue teams to locate survivors. Oceanic predators will usually avoid contact with humans, although any cuts and injuries should be kept out of the water if possible. Shark attack is rare and unlikely, but studies have shown that if the worst should happen, sharp blows to the snout of nose of a shark can deter it.

Offshore Survival Suit

With a survival suit worn you increase your chances of survival considerably. Not only will it insulate you against the chilly seas but you'll be more visible to rescuers.
Fully enclosed in one these only parts of your face are exposed to the elements. Some of the most advanced suits even eliminate this by having a spray-hood and internal re-breather tube for cocoon-like comfort!
The disadvantages of a survival suit are few; It can take some time to don one and you lose some dexterity while wearing it. These aside they are a brilliant piece of kit for any vessel or installation to have in emergency.

Lifeboats

It is in a lifeboat or even a makeshift life-raft that there is a greater chance of being rescued. Ideally the craft will have some kind of shelter on board from the elements. This could be anything from a ground sheet protecting against the sun to a hardened carbon fibre shell.

In the United Kingdom the term Lifeboat can mean the actual craft that the RNLI (Royal National Lifeboat Institution) Rescue Organisation use. These craft are distinguished by the orange coloured paintwork on the hull. However for the purposes of this section assume that Lifeboat means that which survivors are on board.

Modern lifeboats have on board, as a minimum: Flares, water, first-aid kits, sea ink (attracting rescuers), fishing gear, heliograph mirrors, water purifiers, a sea anchor (slows down drifting from wreck to aid rescuers), life jackets and water. There may also be a rain-water collector to gather fresh water that way. There may also be a heater. Not all lifeboats have food, for example offshore platform lifeboats and life-raft do not due to the close proximity / attention of rescuers. Most ocean liners and craft far out at sea do however. Some of the latest lifeboats are nearly unsinkable by the elements thanks to advances in carbon fibre design and the fully enclosed 'submarine' hull.
Attracting rescuers attention can be crucial as even on board a lifeboat poor weather can mean its difficult for even airborne rescuers to spot. Flares / Smoke dischargers are a valuable tool in a survivors arsenal and should be used wisely. They are normally located inside water tight storage containers on lifeboats. Proper care is needed when firing flares as the parachute flare can be lethal if used incorrectly. Hearing a rescue helicopter may not be enough to begin launching them, for best results (unless the weather is ruining visibility) wait for the rescue craft to be at least within visual range ( 1 - 6 miles) before launching.

Note that red flares are for day use and orange for night use (an easy way to remember is that street lights at night light up in sodium orange colour!) they could be hand flares or parachute flares. Use parachute flares initially to attract attention then ignite the hand flares, smoke, strobe flashers to (hopefully) give away your actual position to the rescue craft. The most advanced life boats may have an EPIRB (Emergency Position Indicating Radio Beacon) system on board that (when activated) sends out constant distress signals that rescuers can use as a beacon. Another useful accessory is a radar reflector or simply a large piece of metal (usually vertically mounted) that a rescue crafts radar system can pick up.

Life Raft

Similar to a lifeboat but slightly inferior is the Life raft, all offshore platforms and maritime shipping have these onboard. They are located close to the railings and normally inflate when 'rolled' off the side (via a bungee trigger) if a life boat is unavailable the next best thing (and possible quicker to deploy) is the Life Raft. It usually contains all the supplies a Lifeboat has but without an engine (although oars are usually onboard).

Should rescuers fail to appear or worse still the search is called off then the best solution is to try and make for the nearest land mass. If this isn't possible it might be best to try heading for international shipping lanes and pray for passing ship or vessel. Ration and conserve water as much as possible. Most modern lifeboats have limited propulsion so ocean travel is possible although fuel is a limiting factor. Food is much less useful on board a boat than water, as a person can only last about three days without water compared with about three weeks without food.

Fast Rescue Craft (FRC)

In an emergency if you see one of these craft heading towards you at top-speed you know the cavalry's on its way. Used by the RNLI, Coastguards and offshore it is a brilliant bit of kit for fast travel across water.

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