We tend to be warm water divers which generally precludes diving off the coast of Massachusetts but does provide a good excuse to go someplace warm during the colder months. Generally speaking we go to someplace in the Caribbean twice a year.
Scuba is an interesting sport. It is a sport that demands thoughtfulness and training, but does not require a significant degree of strength, coordination or those qualities that would normally be associated with a ‘sport’, so it is accessible to many people.
Although there are ‘resort courses’ that will give you several hours of course work and then let you jump in the water (under very controlled conditions), one needs to be certified in order to rent gear or to go out on a boat dive. The largest international certification agencies that are currently recognized by most diving outlets for diver certification include:
- ACUC - American Canadian Underwater Certifications Inc. (formerly Association of Canadian Underwater Councils) - originated in Canada in 1969 and expanded internationally in 1984 - certifications recognized worldwide.
- British Sub Aqua Club (BSAC) - based in the United Kingdom, mostly for UK divers and clubs
- CEDIP - European Committee of Professional Diving Instructors - (http://www.cedip.org/) based in Europe since 1992 but international certifications are recognized all over the world. (see Cedip on French Wiki pages)
- Confédération Mondiale des Activités Subaquatiques (CMAS)
- National Association of Underwater Instructors (NAUI) - based in the USA
- Professional Diving Instructors Corporation (PDIC) - based in the USA
- Professional Association of Diving Instructors (PADI) - based in the USA, largest recreational dive training and certification organization in the world
- International Training SDI, TDI & ERDi
- Scuba Schools International (SSI) - based in the USA
- YMCA SCUBA - based in the USA, part of Young Men's Christian Association (YMCA), a Christian related organization (open to all faiths, ages and genders despite the historic name)
Beth and I have certifications from both SSI and PADI. One of the many certifications for recreational diving that can be collected is the EANx (Enriched Air NITROX) certification, or simply known as Nitrox.
The atmosphere is comprised of 78% Nitrogen, 21% Oxygen and 1% misc. gasses. The Nitrox mixture will contain a higher proportion of Oxygen against a slightly lower proportion of Nitrogen. The 'usual' mixtures for recreational diving will be 32% Oxygen or 36% Oxygen. The ‘x’ in EANx will reflect this proportion of Oxygen, so the above mixtures will tend to be designated as EAN32 and EAN36.
Nitrox is mainly used in scuba diving to reduce the proportion of nitrogen in the breathing gas mixture. But, like everything in life, this involves compromise. Reducing the proportion of nitrogen by increasing the proportion of oxygen reduces the risk of decompression sickness, allowing extended dive times without increasing the need for decompression stops but using Nitrox increases the risk of oxygen toxicity and fire. There is also anecdotal evidence that the use of Nitrox reduces post-dive fatigue.