User talk:Farm/TMP

Signal flag A(Alpha) - "I have a diver down - Keep clear"

Informal Recreational diving flag

潜水是一项水下活动，有的需要呼吸装备（水肺潜水和送气式潜水），有的则依靠屏气（自由潜水）。

休闲潜水是一种流行的活动，也被称为运动潜水；而专业潜水（商业潜水，出于科学研究或经济目的）则在水下潜点实施作业。

潜水类型决定了不同的训练、装备类型以及呼吸气体。

潜水包括自由潜水、水肺潜水、送气式潜水、饱和潜水以及深海潜水。

• 
  用monofin自由潜水，上升中
• 
  休闲的水肺潜水员
• 
  送气式潜水员驾驭平台抵达水下工作站
• 
  封闭仓将饱和潜水员从工作台运至高压生命仓
• 
  美国海军大气潜水系统 (ADS)

历史

早在古希腊，商业而不是休闲目的的潜水就已开始，当时柏拉图和荷马有提及将海绵动物门用作洗澡。卡林诺斯岛是潜水捕获海绵动物门的主要地点。通过使用多达15公斤（33英磅）的配重（skandalopetra）来加速下潜，屏气潜水员在5 分钟内可下潜至30米（98英尺）以收集海绵动物门。

潜水的方式

不带呼吸器的潜水

自由潜水

主条目：自由潜水

自由潜水不用任何呼吸设备，仅依靠潜水员的屏气能力，包括简单的屏气潜水以及竞争的极限下潜。

游泳

主条目：游泳

在水里游泳或下潜可以是一项实用的紧急技能，在水上运动和海军安全训练中是重要组成部分。通常而言，从高处跳水也是一项有趣的休闲活动，无论是否带有呼吸器。

浮潜

主条目：浮潜

增加了一根呼吸管，这样可以把脸朝向水底，身体浮在水面。

水肺潜水

主条目：水肺潜水

水肺潜水通过自给式潜水呼吸器，而无需水面送气，这样潜水员在水下就可以灵活移动。

一些水肺潜水员还被称为蛙人，尤其是部队里从事秘密行动的潜水员。

开环

主条目：Scuba set

开环水肺系统将呼出的气体直接排到周围环境，装置包括一个或多个高压潜水空气瓶，空气瓶又和[[潜水呼吸调节器]相连，同时也可能包括另外的应急空气瓶。

再呼吸

主条目：Rebreather

闭环或半闭环呼吸系统重复利用呼出的气体，这样就可以减少用气量。和开环潜水相比，相同的潜水过程，潜水员可以背更小的空气瓶；而对于同样的空气消耗，潜水员可以在水下待更长的时间。再呼吸潜水产生的气泡和噪音也更少，所以在军事、科研和媒体领域，更受欢迎。

送气式潜水

展销会上展示的送气式商业潜水装备

主条目：surface supplied diving

与自带呼吸系统相对的是水面送气，水面通过脐带缆或航空软管提供空气、通讯以及安全线，甚至还可以提供加热的热水软管、视频缆线和空气回收缆线。

Surface oriented diving

Surface oriented, or bounce diving, is how commercial divers refer to diving operations where the diver starts and finishes the diving operation at atmospheric pressure. The alternative is saturation diving.

The diver may be deployed directly, often from a diving support vessel or indirectly via a diving bell. Surface-supplied divers almost always wear diving helmets or full face diving masks. The bottom mix can be air or mixed gas, the decompression mix nitrox or pure oxygen. Decompression procedures include in-water decompression or surface decompression in a deck chamber.

A wet bell with a gas filled dome provides more comfort and control than a stage and allows for longer time in water. Wet bells are used for air and mixed gas, and divers can decompress on oxygen at 12 m.

Small closed bell systems have been designed that can be easily mobilized, and include a two-man bell, a handling frame and a chamber for decompression after transfer under pressure (TUP). Divers can breathe air or mixed gas at the bottom but are usually recovered in the chamber filled with air. They decompress on oxygen supplied through built in breathing systems (BIBS) towards the end of the decompression. Small bell systems support bounce diving down to 120 m and for bottom times up to 2 hours.

An alternative to scuba diving, called "SNUBA" or "hooka" diving, has the diver supplied via an airline from a small cylinder or compressor at the surface. It is used for light work such as hull cleaning and archaeological surveys, for shellfish harvesting, and as a shallow water tourist activity for those who are not scuba-certified.

Saturation diving

主条目：Saturation diving

Saturation diving lets professional divers live and work at depth for days or weeks at a time. This type of diving allows greater economy of work and enhanced safety. After working in the water, divers rest and live in a dry pressurized underwater habitat on the bottom or a saturation life support system of pressure chambers on the deck of a diving support vessel, oil platform or other floating work station. In either case, they stay at a similar pressure to the work depth. They may be transferred in a closed diving bell, also known as a personnel transfer capsule. Decompression at the end of the dive may take many days, but since it is done only once for a long period of exposure, rather than after each of many shorter exposures, the overall risk of decompression injury to the diver and the total time spent decompressing are reduced.

潜水的动机

Professional diver using surface supplied diving equipment performing underwater welding

参见：Recreational diving和Professional diving

Diving may be done for a number of reasons, both personal and professional.

Recreational diving, is purely for enjoyment and has a number of distinct technical disciplines to increase interest underwater, such as cave diving, wreck diving, ice diving and deep diving.

Divers may be employed professionally to perform tasks underwater.

Commercial divers are employed to perform tasks related to industries involving underwater work, including civil engineering tasks such as in oil exploration, offshore construction dam maintenance and harbour works. Commercial divers may also be employed to perform tasks specifically related to marine activities, such as naval diving, including the repair and inspection of boats and ships, salvage of wrecks or aquaculture.

There are a fair number of divers who work, full or part-time, in the recreational diving community as instructors, assistant instructors, divemasters and dive guides. In some jurisdictions the professional nature, with particular reference to responsibility for health and safety of the clients, of recreational diver instruction, dive leadership for reward and dive guiding is recognised by national legislation.

Other specialist areas of diving include military diving, with a long history of military frogmen in various roles. They can perform roles including direct combat, infiltration behind enemy lines, placing mines, bomb disposal or engineering operations.

In civilian operations, many police forces operate police diving teams to perform search and recovery or search and rescue operations and to assist with the detection of crime which may involve bodies of water. In some cases diver rescue teams may also be part of a fire department, paramedical service or lifeguard unit, and may be classed as public safety diving.

Lastly, there are professional divers involved with the water itself, such as underwater photography or underwater film makers, who set out to document the underwater world, or scientific diving, including marine biology, geology, hydrology, oceanography and underwater archaeology.

The choice between scuba and surface supplied diving equipment is based on both legal and logistical constraints. Where the diver requires mobility and a large range of movement, scuba is usually the choice if safety and legal constraints allow. Higher risk work, particularly commercial diving, may be restricted to surface supplied equipment by legislation and codes of practice.

Reasons for diving may include:

Diving activities	Classification	Scuba or Surface Supplied Diving Equipment
aquarium maintenance in large public aquariums	commercial, scientific	Scuba, SSDE
boat and ship inspection, cleaning and maintenance	commercial, naval	SSDE, occasionally scuba
cave diving	technical, recreational, scientific	Scuba, occasionally SSDE
civil engineering in harbors, water supply, and drainage systems	commercial	Almost exclusively SSDE
crude oil industry and other offshore construction and maintenance	commercial	Almost exclusively SSDE
demolition and salvage of ship wrecks	commercial, naval	SSDE, sometimes scuba
professional diver training	professional	SSDE or scuba as appropriate
recreational diver training	professional, recreational	Scuba
fish farm maintenance	commercial	Scuba, SSDE
fishing, e.g. for abalones, crabs, lobsters, pearls, scallops, sea crayfish, sponges	commercial	Scuba, SSDE
frogman, manned torpedo	military	Scuba
harbor clearance and maintenance	commercial, military	Almost exclusively SSDE
media diving: making television programs, etc.	professional	Scuba, occasionally SSDE
mine clearance and bomb disposal, disposing of unexploded ordnance	military, naval	Scuba, occasionally SSDE
pleasure, leisure, sport	recreational	Almost exclusively scuba
policing/security: diving to investigate or arrest unauthorized divers	police diving, military, naval	Scuba
search and recovery diving	commercial, public safety, police diving	Scuba, SSDE
search and rescue diving	police, naval, public service	Scuba, occasionally SSDE
spear fishing	professional (occasionally), recreational	Scuba
stealthy infiltration	military	Scuba
surveys and mapping	scientific, recreational	Scuba, SSDE
scientific diving (marine biology, oceanography, hydrology, geology, palaeontology, diving physiology and medicine)	scientific	Scuba, occasionally SSDE
underwater archaeology (shipwrecks; harbors, and buildings)	scientific, recreational	Scuba, SSDE
underwater inspections and surveys	commercial, military	SSDE, sometimes scuba
underwater photography	professional, recreational	Scuba, SSDE
underwater sport	recreational	Snorkel, breathhold and Scuba
underwater tour guiding	professional, recreational	Scuba
underwater tourism	recreational	Scuba, occasionally Snuba
underwater welding	commercial	Almost exclusively SSDE

• 
  Early underwater photographer (1960's)

潜水的训练

主条目：Diver training

Underwater diver training is normally given by a qualified instructor who is a member of one of many diving training agencies or is registered with a government agency.

Basic diver training entails the learning of skills required for the safe conduct of activities in an underwater environment, and includes procedures and skills for the use of diving equipment, safety, emergency self-help and rescue procedures, dive planning, and use of dive tables.

Some of the skills which an entry level diver will normally learn include:

• Ear equalization and equalisation of other air spaces.
• Underwater breathing – the skill of breathing through the apparatus.
• Mask clearing – the skill of clearing water from the mask.
• Air sharing – assisting another diver by providing air from one's own supply, or receiving air supplied by another diver.
• Emergency ascents - how to return to the surface without injury in the event of a breathing supply interruption.
• Use of bailout systems (professional divers)
• Buoyancy control – neutral buoyancy allows the diver to move about underwater comfortably.
• Diving signals – used to communicate underwater. Professional divers will also learn other methods of communication.

潜水的危害

主条目：Diving hazards and precautions

Divers face specific physical and health risks when they go underwater with scuba or other diving equipment, or use high pressure breathing gas. The hazards can be listed under several categories:

• The aquatic environment
• Use of breathing equipment in an underwater environment
• Exposure to a pressurised environment and pressure changes, which includes:

• Pressure changes during descent
• Pressure changes during ascent
• Breathing gases at high ambient pressure

• The specific diving environment
• Pre-existing physiological and psychological conditions in the diver
• Diver behaviour and competence
• Failure of diving equipment other than breathing apparatus
• Hazards of the dive task and special equipment
• Hazards related to access to and egress from the water.

The presence of a combination of several hazards simultaneously is common in diving, and the effect is generally increased risk to the diver, particularly where the occurrence of an incident due to one hazard triggers other hazards with a resulting cascade of incidents. Many diving fatalities are the result of a cascade of incidents overwhelming the diver, who should be able to manage any single reasonably foreseeable incident.

The assessed risk of a dive would generally be considered unacceptable if the diver is not expected to cope with any single reasonably foreseeable incident with a significant probability of occurrence during that dive. Precisely where the line is drawn depends on circumstances. Commercial diving operations tend to be less tolerant of risk than recreational, particularly technical divers, who are less constrained by occupational health and safety legislation.

According to a North American 1972 analysis of calendar year 1970 data, diving was, based on man hours, 96 times more dangerous than driving an automobile. According to a 2000 Japanese study, every hour of recreational diving is 36 to 62 times riskier than automobile driving.

Consequences of diving hazards range from merely annoying through to rapidly fatal, and are listed in the article on Diving hazards and precautions and discussed in detail in other articles linked from that article.

潜水的其他形式

Diving in submersibles

Submarines, submersibles and 'hard' diving suits enable undersea diving to be carried out within a dry environment at normal atmospheric pressure, albeit more remotely. Underwater robots and remotely operated vehicles and also carry out some functions of divers at greater depths and in more dangerous environments.

Diving by other animals

Humans are not the only air-breathing creatures to dive. Marine mammals such as seals, dolphins and whales, dive to feed and catch prey under the sea as do penguins and many seabirds, as well as various reptiles: turtles, saltwater crocodiles, seasnakes and Marine Iguanas. Many mammals, birds and reptiles also dive in freshwater rivers and lakes.

延伸阅读

• Cousteau J.Y. (1953) Le Monde du Silence, translated as The Silent World, Hamish Hamilton Ltd., London; ASIN B000QRK890
• Lang M.A. & Brubakk A.O. (eds., 2009) The Future of Diving: 100 Years of Haldane and Beyond, Smithsonian Institution Scholarly Press, Washington DC