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Considering Visibility

Unlike our blue water counterparts in the likes of the Mediterranean, poor visibility is a factor that we need to take into account at any time during the year and particularly during the winter in Ireland. Poor visibility can ruin the experience of a snorkel and cause a safety concern for a diver. At any time of the year, it’s a great relief to get to a dive site to hear the words “it's crystal clear” rather than hearing someone say it's “Chicken soup” or something that resembles a material you would build a house with. For any diver, this can be the equivalent of driving in a heavy fog where great care should be taken. Methods of dealing with this type of hazard for diving would be dealt with in diver training. While this typically won’t affect a surface snorkel, if you are planning to submerge at all it's worthwhile to take heed of some basic practices.

Judge the visual distance

A dive sites visibility is judged by an estimate of how far you can see horizontally. It’s not unusual to hear measurements given in feet or meters, or by someone telling you they can’t see their hand in front of their face. A diver will have ways to manage to be able to see other divers around them by use of visual markers or by touch (yes it can be that bad). When snorkelling a good way to judge the quality of the water is to stand upright, preferably floating so as not to kick up any silt or sand on the sea bed, and see can you see your fins clearly or not. This will give you a good rule of thumb indication of distance and quality.

Where is better or worse

The vast majority of the time it is found that the visibility at the shore is typically worse than out at sea because of the effect of the tidal wash of any silt or sand which will gather at the shore. Poor visibility can be caused by a number of factors which are mostly to do with weather conditions but other factors can also come into play.

When snorkelling from the shore try to look for somewhere that has calm waters like in a cove or that is protected by a pier. Look out for areas that have rocky surfaces and avoid silty areas where possible, particularly in winter. There are plenty of technical reasons why visibility can be poor. Salinity, where freshwater sources meet cold water sources, can cause visual discrepancies in the water; temperature and light levels can all have an effect but look for the simple things first. There is no greater hindrance for a diver than a foggy mask and while not often considered as a factor this can be a particular problem when a mask is new. New masks have a thin layer of grease on the inside of them that can be removed with toothpaste or by washing with soapy water.

Chances are if you have poor visibility in the environment then somewhere in the vicinity, there is probably a swell or a current that you may or may not be aware of. Speaking to the local lifeguard (if available), looking at a reputable app or speaking to other divers in the area will give a better idea of the conditions.

To sum up…

It might sound like an obvious thing to check before heading out but poor visibility can ruin a good snorkel/shore dive. It is worth keeping in mind that it can also be dangerous in some cases. Be careful when selecting the location, equipment and conditions before heading out. It is worth remembering that surface snorkelling is not only about what's below the surface but also about what you can see above, there is still plenty to see and explore even if there is little to see below.

Have you experienced bad visibility on a snorkel or dive? Tell us about your experience in the comment section below.

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