| EAD |
Equivalent Air Depth. A means of equating gas mixes (such as Nitrox) to air. |
| EANx |
Enriched Air NITROX. A mixture containing more than 21% oxygen. |
| EAR |
Expired Air Resuscitation. Now called AV. |
| Ebb Tide |
A falling tide. |
| Elevation |
Height above mean sea level (msl). |
| END |
Equivalent Narcosis Depth. Means of equating the relative narcotic influence of inert gases to air. See EAD |
| EPIRB |
Emergency Position Indicating Radio Beacon. A compact, buoyant, self-contained radio transmitter. When activated emits a radio signal to a satellite for a minimum of 24 hours. |
| Equalisation |
The act of forcing air into an open space to offset increasing hydrostatic pressure. This can be applied to such spaces as a dive mask or the diver's ears, and prevents what is known as a squeeze. |
| Equinoctal Tides |
The lunar and solar tide generating forces are greater than average when the Moon and Sun have low declination and vice versa. This will occur when the Moon (new and full) has a low declination near the equinoxes (Vernal (Spring) 21st March and Autumnal (Autumn) 23rd September of each year. The biggest spring tides of the year will occur after a new or full moon which is in Perigee near the Equinox. |
| ERD |
Extended Range Diver (BSAC) |
