How and why scuba gauges give a diver critical information while scuba diving?
Scuba gauges give a diver three very important pieces of information:
3. Air Consumption
This information enables a diver to stay within safe time and depth limits and avoid running out of air. There are many different devices on the market to help with this, from simple gauges to complex digital consoles.
If a diver is not using a dive computer to monitor their nitrogen, they dive according to approved dive tables. To use dive tables properly, a diver needs to track their downtime. This can be done with a good dive watch. Two things make a good dive watch: water resistance and a rotating bezel.
1. Water Resistance. Good dive watches are rated to a depth in meters or feet (e.g. 200 feet) or a pressure rating in atmospheres (e.g. 4atm). Even though most divers probably won’t dive below 130 feet (the recreational dive limit), a good dive watch should be rated to 200 feet. Note: There is a difference between “water resistance” and “waterproof”. A “waterproof” watch is what you would wear in the shower, but would probably start leaking at 15-20 feet.
2. Rotating Bezel. A bezel is an adjustable ring on the face of the dive watch with a pointer indicator. At the beginning of a dive, the pointer on the bezel is aligned with the minute hand where it stays though out the dive. At the end of the dive, you compare the difference between the bezel and the minute hand to find out the length of the dive. The bezel should only move “counterclockwise”. It is possible to accidently move the bezel during a dive. Because of this, watchmakers make sure any accidental movement will turn the time in a conservative direction, making the dive longer rather than shorter.
Another important part of scuba gauges is a depth gauge. A depth gauge enables a diver to keep track of their depth even if they cannot see the water’s surface. Gauges can be either an analog (needle-and-dial) device or a digital device. Both work in the same way. They measure the surrounding water pressure and convert this into an accurate reading of your depth. Another feature of a good depth gauge is a maximum depth indicator. This tells a diver their maximum during a dive and must be reset after each dive.
Another equally important part of scuba gauges is a submersible pressure gauge (SPG). This is connected to the first stage with a high-pressure hose and measures the pressure of the air in the tank. The SPG is much like the gas gauge on a car. At the beginning of a dive, a diver starts with a full tank. This should be about 3000 psi or 200 bars. As the diver breathes during the dive, the gauge will move slowly downwards. This allows the diver to have enough air left in the tank to:
1. Make a slow, safe ascent
2. Make any necessary decompression stops
3. Inflate their BCD once at the surface
4. Breath from the regulator if the surface conditions are rough
A submersible pressure gauge also allows a diver to stop diving with air still in the tank. This keeps contaminants from entering the tank due to no air pressure.
Wrist Depth Gauge
Scuba gauges come in two basic styles. Stand alone gauges or gauge consoles. Stand alone gauges such as a wrist mounted depth gauge or a submersible pressure gauge attached to the first stage of a regulator are great backups when using digital gauges. Gauge consoles allow divers to have all their gauges in one place.
Although less easy to read, analog gauges sometimes give slightly more accurate readings than digital gauges, particularly at shallow depth.
Submersible Pressure Gauge
Choosing Scuba Gauges
When choosing scuba gauges, remember to look for:
1. Easy-to-read numbers
2. Luminescent dial or back lighting options
3. Rotating/swivel mounting
4. Easy disassembly for cleaning or replacing parts
5. Good warranty
Dec 01, 2008 |
Aeris Max Depth Analog 2 Gauge Console