SPG, no-stop time, buddy check: every diving term explained simply — your cheat sheet before the other guides assume you already know them.
"What on earth is an SPG, and why does everyone nod along during the buddy briefing when someone says BWRAF like it's a normal word?" — honest answer: diving comes with its own language, cobbled together from physics, agency jargon, and gear names, and every guide, course, and boat briefing just assumes you already know it. This glossary explains the key terms before you trip over them — read it once before you start the intro guide, and everything will click from line one.
Start with the gear, then everything else falls into place.
Your ABC gear (ABC-Ausrüstung) is the basic trio: mask, snorkel, and fins — that's what it's called in every diving language on earth. To stay down longer than a few breaths, you add SCUBA (Self-Contained Underwater Breathing Apparatus, in German simply Gerätetauchen): a compressed-air tank plus a regulator (Lungenautomat, also Atemregler). It has two stages — the first stage (erste Stufe) sits on the tank and drops the huge tank pressure to a constant intermediate pressure, while the second stage (zweite Stufe) sits in your mouth and delivers air at exactly the pressure around you. The octopus (Oktopus) is the conspicuously yellow backup second stage on your setup — for your buddy, in case theirs runs dry.
The buoyancy control device, or BCD (Tarierjacket), is the vest you use to control your buoyancy: add air, you rise; release air, you sink. To sink at all instead of bobbing like a cork, you wear weights (Bleigewichte) in the right amount. Your submersible pressure gauge, or SPG (Finimeter), shows how much air is left in your tank, while your dive computer (Tauchcomputer) tracks your depth and dive time — together, your most important early-warning system. And because water steals body heat far faster than air, a wetsuit (Neoprenanzug) in the right thickness for your dive site rounds out the kit.
Underwater, pressure changes with every meter — and your body feels it first in your ears. Equalizing (Druckausgleich) means actively pushing air into your middle ear so rising ambient pressure doesn't push your eardrum inward. The classic technique is the Valsalva maneuver (Valsalva-Manöver): pinch your nose, exhale gently against it. Safer and smoother is the Frenzel maneuver (Frenzel-Manöver), where you don't push air from your lungs at all but shove it upward using only your throat muscles. Rule of thumb: equalize early and often, never wait until it pulls.
Buoyancy control (Tarieren), or neutral buoyancy, is the state where you hover in the water without sinking or rising — weightless, almost like floating in space. You fine-tune it with your breathing: inhale deeply and you rise slightly, exhale and you sink slightly. Add to that your trim (Trim): a flat, streamlined horizontal body position in the water that cuts drag and lets you glide efficiently, instead of hanging at an angle like a half-open parachute.
Two timing terms every dive computer displays: your no-stop time, or no-decompression limit (Nullzeit), is how long you can stay at a given depth without your body absorbing so much nitrogen that you'd be forced into stops on the way up. The safety stop (Sicherheitsstopp) is mandatory regardless: a few minutes around 5 meters before you fully surface, giving your body time to off-gas any excess nitrogen calmly.
Diving is a team sport, not a solo adventure. The buddy system (Buddy-System) means you always dive with a partner who becomes your most important safety system if something goes wrong. Before every dive comes the buddy check (Buddy-Check), often following the mnemonic BWRAF (weights, BCD, releases, air, final okay), where you check each other's gear. If your partner runs out of air, you share yours through air sharing (Air Sharing): one of you hands over the octopus, and together you make a slow, controlled ascent. That exact situation is called out-of-air (Out-of-Air), and it's the reason the octopus is mandatory gear.
A barotrauma (Barotrauma) is an injury caused by pressure change — most commonly in the middle ear when equalizing comes too late, or more seriously in the lungs when you hold your breath during ascent instead of breathing continuously. Decompression sickness, or DCS (Dekompressionskrankheit), happens when you ascend too fast and the nitrogen dissolved in your tissue turns into gas bubbles — like a shaken soda bottle opened too quickly. Both risks drop sharply if you follow the basic rules: ascend slowly, never hold your breath, do your safety stop. Before every dive there's also the pre-dive check (Pre-Dive-Check): a systematic inspection of O-rings, hoses, the valve, and the BCD, so no nasty surprises wait for you underwater.
To dive with a tank at all, you need a certification (Tauchschein), usually the Open Water Diver (Open Water Diver), issued by one of the major agencies like PADI, SSI, or CMAS. They differ in details, but the basic structure is similar everywhere: theory, practice in calm water, and real dives in open water (Freiwasser) — meaning the actual ocean or lake instead of a pool. Certification isn't the finish line, it's the start of a ladder with progressively more depth and specialties.
One more term you'll run into everywhere: scuba diving (Gerätetauchen) is by far the mainstream form of the sport — diving with a tank and regulator, as described throughout this glossary. Alongside it sit dedicated disciplines like freediving (Freitauchen, diving without a tank, on a single held breath), technical diving (technisches Tauchen, for greater depths and wrecks, with more tanks and more training), and cave diving (Höhlentauchen) — each with its own rulebook, but all built on the same foundation of equalizing, buoyancy control, and the buddy system.
Pin this one sentence to the wall: "Keep breathing, equalize early, ascend slow." Almost every term in this glossary circles back to exactly those three reflexes — whether it's no-stop time, barotrauma, or safety stops, it's all about giving your body time to adjust to pressure. Whenever a new term confuses you, just ask yourself: what does this have to do with pressure or air?
### What is a buddy check in diving? A buddy check is the mutual gear inspection you and your dive partner do right before entering the water, often following the mnemonic BWRAF (weights, BCD, releases, air, final okay). You check each other's tank valve, inflator, and releases — most underwater incidents would have been caught at the surface.
### What does no-stop time mean in diving? No-stop time (also called the no-decompression limit) is how long you can stay at a given depth without your body absorbing so much nitrogen that you'd be forced into decompression stops on the way up. Your dive computer recalculates it continuously and shows how much time you have left.
### What's the difference between scuba diving and freediving? Scuba diving means staying underwater for hours using a compressed-air tank and regulator — the mainstream form of the sport. Freediving skips the tank entirely: you dive on a single breath, as deep and as long as your body allows, then return to the surface to exhale.
### How does equalizing work in diving? As you descend, ambient pressure rises and pushes your eardrum inward. Equalizing actively pushes air into your middle ear, usually via the Valsalva maneuver (pinch your nose, exhale gently against it) or the safer Frenzel maneuver. Key rule: start early, repeat often, never force through a blockage.
### What is decompression sickness (DCS)? DCS happens when you ascend too fast and the nitrogen dissolved in your tissue turns into gas bubbles — similar to a soda bottle opened too quickly. Those bubbles can block blood vessels and cause anything from pain to paralysis. Ascending slowly and doing a safety stop cut the risk dramatically.