Technical Diving in Sharm-el-Sheikh

The peculiarity of wreck diving is that a diver should know the object well, whether it is a shipwreck, a plane crash or ruins of an ancient vessel with gold-loaded holds. Naturally, technical divers should be aware of gas laws and human physiology - it's absolutely essential to have such kind of knowledge.
Cave diving is technically different from penetration diving (entering a wreck). One should know cave types and their location and explore cave topography in advance. Professional divers admit that the most interesting caves are located in Mexico, Florida, Cuba and here, in Egypt. The Blue Hole in Dahab, is truly spectacular. The hole starts at the coastal sandbank, steeply falling down and rising to a sheer reef wall at a depth of 52 metres. The bottom of the arch-like hole is 1l0-metre-deep and 150-metre-wide and connects with the open sea through a tunnel 26 meters long.

It's easy to explain why divers have to use trimix for deep diving (a breathing gas mixture, consisting of oxygen, helium and nitrogen in various proportion): at depths greater than 40 regular air inhaled by recreational divers at depths up to 18 meters becomes unfit for breathing because of nitrogen contents. Almost all people suffer from nitrogen toxicity at 40 metres, which prevents from thinking clearly. Decompression stops at surfacing allow to prevent decompression sickness, also known as the "bends". During a dive and at great depths the body is saturated with helium and nitrogen that tend to outgas during the ascent. This phenomenon can be described as the champagne effect - gas bubbles form in tissue, which can be lethal if the bubbles are not released naturally through lungs at prescheduled decompression stops (to plan the stops special decompression tables are used, with recalculated depth and time of stops). With a 1-minute dive to 150 metres the ascent can take from 1.5 to 4 hours.