Visibility While Diving

Visibility is a vital aspect of scuba diving and can basically be defined as the distance at which an object can be identified under water. It is, at first, not easy to estimate visibility but one does get better at it with experience.

One can measure visibility from two aspects, either horizontal or vertical visibility.

Horizontal visibility refers to how far one can see ahead. Vertical visibility, on the other hand relates to how far one can see when looking up or down. During a dive, the horizontal visibility plays a more important role, as this will affect the diver’s general view under water, as well as being able to see your dive buddy at all times.

There are various factors which will influence the visibility during a dive. The amount of light entering the water will greatly affect the diver's visibility. This is determined by cloud cover, how rough the water surface is, and also the angle at which the light hits the water. When diving in shady areas or if embarking on a cave dive, one can generally expect poor visibility, whereas other areas will be more prone to clear waters, with excellent visibility. The sun is more intense close to the equator, resulting in a greater penetration of light into the water.

The time of day, will have an effect on light penetration. At midday, when the sun is directly above, it provides impressive light levels, As the sun moves towards the horizon, the visibility will decrease.

The sea conditions will also determine the amount of light in the water. Visibility will generally be greater in tranquil waters, as more light is reflected away in rough seas.

Although light has an advantageous effect on visibility during diving, excess light can be detrimental, as it also leads to the accelerated growth of algae, which can drastically decrease visibility. Some sponges and corals help alleviate this problem and assist in providing amazingly clear waters.

Another factor which will affect underwater visibility is the movement of silt and sand in the water. During a storm, waves and rough seas disturb the particles which normally lie on the sea bottom. Try to avoid excessive contact with the bottom while diving, as this force will aggravate the silt and decrease visibility. Fine silt is known to take far longer to settle than heavier gravel or stones.

To counteract any problems when diving in waters with poor visibility, divers should always make sure that they plan the dive properly. If you have chosen a new dive site, ask other divers, who know the location, for their input.

When visibility is low, a dive light will assist you in keeping track of your dive buddy but won’t really help you to see ahead. This is due to the particles which float in the water. Chemical glow sticks and reflective tape attached to your diving equipment can be useful in assisting where visibility is poor.

Always take your time, entering the water feet first, and making a conscious effort to familiarize yourself with your surroundings. One of the most effective ways to descend in waters where the visibility is poor, is to make use of an anchor line from the dive boat. This will help prevent you from becoming disorientated. due to decreased visibility If you do however become disorientated at any time during your dive, close your eyes for a while, try to relax and breathe deeply.

Before a dive, practice various forms of communication. Hand signals will not be suitable if the visibility is particularly bad. In this case making use of sound signals or light signals will be the most effective form of communication.

Despite the fact that one may be diving with decreased visibility, it is possible to have an exceptionally rewarding dive, if planned correctly.