Allowing the water current to move the diver down current, this is one of the most relaxing methods to dive.
Typically done in rivers or the ocean
Example - in Cozumel the boat takes the divers toward the south end on the island, the current runs from south to north, the divers exit the boat and drift north, the boat follows the trail of bubbles from the divers, when the divers surface the boat is waiting for them.
Night diving
Diving after sunset & before dawn reveals new animals that come out at night and corals that open at night to feed. Many divers enjoy this more than diving during the daylight.
Requires a primary and back-up light source. Typically water proof flashlights designed for scuba diving. Additionally scuba diver wear marker lights to help locate and identify them. Cylume Sticks were popular but environmental concerns as phasing them out in favor of battery powered glow sticks.
While night diving divers tend to move slower and more deliberately than during the day light. This leads to a more relaxing dive.
Requires special training to enter and safely exit a cave - prevent your own death - do not enter a cave unless you and your buddy are trained cave divers.
Many of the best diving sites are off shore and the boat provides access to these sites.
Six pack is a slang term for a small boat that can carry up to six divers.
Typically very fast boat with twin outboard engines
"Cattle boat" a slang term for a large boat that take a large group of divers
Altitude diving.
Diving in a body of water located above 1000 feet above sea level. Requires additional training and modified dive tables. Diver must limit the ascent rate to 30 feet pr minute or less.
Lake Tahoe would be an example of a location where altitude diving is done.
Communicating
Sign language: In most situations communications is facilitated with the use of simple hand signals. The most basic ones: Thumbs up = lets go up, thumbs down = lets go down, circle with thumb and index finger = I'm OK. Are you OK?, "cutting" throat with a flat hand = I'm out of air, wobbling a flat hand = something is wrong.
Using a torch/flashlight: The focused beam of a torch can be used for basic signalling as well. Drawing a circle on the ground in front of buddy = the OK signal, waving the torch = attention please!
Voice: When using special equipment, voice can be used for communication. Equipment usually consists of a full face mask with a submergible microphone and speaker and either a hard wired telephone-like setup or a through-water supersonic radio-like system.
