Sea survival means surviving maritime isolation and the military training directed at that task. After the loss of an aircraft, abandonment of a ship or separation from their own force, personnel in the water or aboard available survival equipment must preserve breathing, body heat and functional ability. They must also contend with a changing location and limited means of being located and recovered. The German term is Überleben auf See.
Flotation and protection serve different purposes
Keeping the mouth and nose above the surface takes effort. A suitable, correctly fitted lifejacket provides buoyancy and reduces that effort. Protective clothing limits cooling, while a liferaft lifts the body out of the water and may also provide shelter from wind, spray and sun. Which of these functions are available depends on the equipment actually carried and still accessible after the incident. A floating object, a one-person raft and a crew raft offer very different possibilities.
Sudden contact with cold water can cause an involuntary gasp and initially uncontrollable breathing. Inhaling water can cause drowning during this early stage. Using available buoyancy and reducing unnecessary movement helps keep the airway out of the water until breathing becomes controllable. The person can then assess the surroundings and a reachable next objective.
A different loss of function may follow: cooling of nerves and muscles weakens swimming, grip and finer hand movements. This can occur before later cooling of the body core impairs consciousness. Necessary fastenings and accessible signalling devices therefore need attention early, after breathing control has returned. In the water, available protective clothing is fastened to reduce cold water flushing through it. A purpose-designed spray hood on the lifejacket protects the mouth and nose against spray.
Liferafts and floating objects: assessing reachability
A nearby usable floating object or liferaft can considerably improve the situation. The decisive question is whether the person can reach it with their present strength and hold on or get aboard. Wind can move a raft faster than an exhausted person can swim. A short attempt to reach it therefore needs observable progress towards the objective. Continuing to fall behind despite the effort uses strength and accelerates cooling in cold water.
If there is no reachable objective, the remaining option is to use available buoyancy and drift as still as possible. Keeping the arms close to the body and the legs together reduces the body surface exposed to cold water, where the flotation aid supports that position with the airway clear. Even getting partly onto a load-bearing object reduces water exposure. A person without sufficient buoyancy may instead need to keep moving to maintain a clear airway; a heat-conserving posture must not take them underwater.
Boarding a raft is especially difficult alone. Its available handholds and boarding aids have to be used with whatever hand and leg function remains. Whether others can assist depends on who has reached the raft and can still act. A one-person raft carried out of a jet creates a different situation from the shared survival equipment of a larger aircraft crew.
Wetness, wind and heat on the liferaft
After boarding, the actual people and equipment present and the condition of the raft need checking. Water inside, visible leaks and damaged protective parts determine the work required and what the available equipment allows. Wet clothing can continue cooling the body out of the water, particularly through wind and evaporation. Bailing, protection against wind and spray and an available cover reduce that exposure. Huddling can conserve heat, but the raft must remain stable.
A closed cover still requires ventilation and an outward lookout. Under strong sun, shade and airflow matter, while unnecessary work adds heat and fluid loss. Weakness, headache and nausea make further action harder; confusion can jeopardise operation of survival and signalling equipment. Seawater worsens the water deficit: eliminating its additional salt makes the body lose more water than it gained by drinking it.
Drift changes the location
Current carries a person with the surrounding water; wind also acts on the parts of a raft projecting above the surface. The person, raft and a separately floating item of equipment can therefore move apart. An available sea anchor belonging to the survival craft creates resistance in the water and slows its drift. It does not hold the raft at a fixed point on the seabed. The location continues to change while it is deployed.
A reported incident position describes a place at a particular time. After prolonged drift, it may be far from the personnel's present location. The same problem arises when a distress beacon remains at a wreck or drifts separately from the survivors: search teams may find the transmitter first. An available voice or data connection therefore also serves to report updated positions with their times, the personnel's condition and changes in the situation.
Alerting and local search aids
An activated distress beacon for the Cospas-Sarsat satellite system can support alerting and location of its transmitter. Operation and deployment must match the particular design. A personal PLB is kept above water with its antenna in the prescribed position; the body should obstruct the radio path as little as possible. A maritime EPIRB may be designed to operate in a particular floating attitude and is secured to something that will not pull it under. A transmitter drifting away separately makes it harder to associate its location with the personnel.
For search units already nearby, a whistle, light and radar SART perform different tasks. A radar SART responds to suitable radar pulses and produces a conspicuous search signal on a compatible radar display. Processing and settings can nevertheless suppress that signal. An interrogation indication on the SART then shows that radar has triggered it while the crew has yet to recognise the survivor. Similarly, an available Return Link Service on a distress beacon confirms reception and forwarding of the alert; it does not report that recovery has begun.
Under enemy threat, a visible signal also creates a detection risk. Lights and other conspicuous signals draw attention to the position; radio emissions can be located. The choice of available means therefore has to fit mission communications instructions and the situation actually observed. When contact is made with friendly recovery forces, the current location and the person are verified separately. A device identifier and coordinates do not replace prepared personnel authentication. Sea conditions, the person's condition, the threat and the capabilities of the forces available then determine the possible recovery.
National training role and the distinction from HUET
The German Navy trains aircrew in Überleben auf See. Survival equipment and tasks are adapted to jets, helicopters or larger aircraft. One training model combines theory and familiarisation with survival equipment, water familiarisation, indoor practice and a subsequent open-sea exercise. Time aboard the raft and recovery by helicopter winch are also practised. Moving from a sheltered training hall into wind, waves and rotor wash changes the difficulty of the same hand movements.
The Royal Navy brought Maritime SERE and underwater escape training together at Yeovilton. Leaving the submerged cabin was followed by making safe at the surface, using a personal raft and winch recovery. The US Air Force also uses Water Survival Training for preparation for a water landing. In an aircrew refresher conducted by the 908th Flying Training Wing, practice included the actual personal flotation equipment and transfer into liferafts. The individual's own equipment determines which of these transitions they have to make.
HUET means Helicopter Underwater Escape Training and addresses immediate self-rescue from a submerged helicopter. Sea survival explains the subsequent task at the surface and exposure to the maritime environment. A course may combine both tasks. The environmental term sea survival, however, does not assign a SERE level or specify the contents of a complete land-evasion or captivity-training programme. Those depend on the national training system and the isolation and exploitation risk of the particular role.