Definitions

 I have been using a lot of acronyms, and will continue to in the name of efficiency. That said, I'm going to list them, as well as what certain other things actually mean, so you can follow along (also so I can follow along....so many things to remember!)

SCUBA: Self Contained Underwater Breathing Apparatus...also a thing people do when they think they have more money than they actually do....Also a sport that is very gadget-heavy. There is ALWAYS One. More. Thing to get. Or something wears out. Or a better version comes along 3 months after the return policy expires. Or it comes out in another color.

PADI: Professional Association of Dive Instructors. Also an agency that trains and certifies people for SCUBA diving. Capt is a PADI instructor, so he can train people to become divers

SSI: SCUBA Schools International. Another certification agency. Capt is also an SSI instructor

DAN: Diver's Alert Network: A multifold agency that handles the medical issues associated with diving. A DAN certified person is, in essence, an EMT (Emergency Medical Technician) trained in the emergency treatment of dive/marine injuries. DAN also provides medical insurance coverage for dive trips. Capt is also a DAN instructor- so he can train people to be DAN certified.

Regs: regulators.....those things that have tubes and hook onto the top of the tank and go to the second stage part that the diver sticks in his/her mouth. They take the high pressure compressed air in the tanks and stage it so it can be breathed without blowing your lungs up.

Octo: a secondary second stage regulator. for redundancy/safety. It has a yellow hose and reg mouthpiece for easy identification in a panic situation.

NITROX: also called EANx....Enriched Air Nitrox and the x is the percentage of enrichment. We breathe 21% Nitrox...Nitrogen/oxygen. EANx/Nitrox, when it's used in SCUBA diving, is a breathing gas blend with a higher percentage of oxygen...the x stands in for the percentage. So EAN32 is 32% oxygen, and so on. The advantage to breathing enriched is that your intervals between dives are shortened, and you have less fatigue after the dives. You can also generally stay in the water longer because you're absorbing less nitrogen.

BCD: Buoyance Compensator Device...a fancy pants name for that vest thing the tank is strapped to, all your hoses and bits and pieces are attached to, and can cost as much as your left kidney. It has bladders in the back that you can fill with air to allow yourself to either float on the surface, or release the air to sink into the water, and use to maintain "neutral buoyancy in the water...that is, neither sink to the bottom nor float to the top. Skilled divers know how to manage their buoyancy to the point where they need neither extra weights nor extra air in the BCD. I am not one of those divers.  Yet.

Weights: Yes. Most divers strap weights to their waist in a belt, or have integrated weight pockets in their BCD. The weights are necessary because if you have a big tank of compressed air on your back, it floats. If you're wearing a wetsuit, you'll float. You need something to counteract all that. Thus, weights.

Wetsuits: You know, makes you look awesome because they're a tight neoprene whole-body girdle that also happens to keep you warm in the water. If only they were comfortable on land. Sigh. It's also near impossible to sink in one because it's foam, unless you have on weights.

Spit: a thickish goo you rub on the inside of your mask to keep it from fogging up when you're underwater. No seriously, it is. And it's better than the stuff after which it's named. Comes in a bottle and there's always someone on the boat who forgets theirs and is borrowing yours.

Viz: Short for visibility...that is, how far you can see underwater. "How's viz?" "Fabulous! Gin-clear!" or maybe "It sucked! I couldn't see Sarah's hot pink fins from 3 feet away!"

Safety-Stop: Without going into the physics of deep diving and nitrogen absorption issues, a safety stop is a point at about 15 feet down where you stop on your ascent at the end of the dive and wait 3 minutes, to help facilitate the reabsorption of nitrogen and keep from getting The Bends. It's also a good spot to swap hairy eyeballs with barracuda. 

No seriously. They just hang there and accuse you of not being a small fish.

More terms to come as I think of them. Also, if you have any questions, please ask! If I can't answer them I know someone who can.