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Tuesday, 27 January 2015

Finding your Path underwater- Navigation by view

So, at the end of last year (2014), we started a blog series with regards to underwater navigation. Essentially, the concern is that instructors are training Scuba Divers to go Scuba Diving with a similarly qualified diver but, with the very limited Navigational Skills training on the initial training courses, can we really say we have given them the tools they need to dive without a guide!

We began discussing Navigation techniques that divers (of all level) can employ to find their way around a dive site and previously talked about the use of an Underwater Compass. This week we will look at using Natural Navigation to find your way around a Dive Site.

Using Natural Navigation involves looking around to get markers that can be used to find your way out to the main attraction of a dive and then back to the starting point.

Sometimes, when scuba divers use tools such as the compass, they spend a lot of time focused on the tool and miss portions of the dive. The fact that divers are required to look around when using natural navigation, means it doesn't get in the way of enjoying your dive and you still get to enjoy your surroundings fully.

To illustrate this tool, let me use a local dive site in Cyprus, The Blue Hole, where the main attraction
is a small cave at 18m.

If I were giving divers a verbal map to navigate this dive site using natural navigation, it would begin on the surface where you can see 2 big rocks that stand up out of the water and you can see that they overlap underwater, creating a little pathway.

Once in the water, divers swim along this path, coming to a shallow rocky shelf that they would swim over to find a channel that runs parallel to the diver's direction of travel that is approximately 5 metres deep.

Follow this channel to the right and you will find a big rock that looks like the Millennium Falcon from Star Wars, behind which, is a little arch in the rock wall that we swim under.

Continue in the same direction of the arch, over a rocky bottom until you come to another channel with a sandy bottom and a bridge of rock crossing over it. Keep going over this and eventually you arrive at a precipice, where the depth drops.

You will also have seen a gradual increase in the depth of the bottom you have followed in the first part of this dive from around 5m to 10m.

At the precipice, it looks like a basin ahead of you full of sea grass. Drop down here and you will be at around 16 metres but to the left there is a large, flat rocky bottom that forms the side of the basin and rises up to about 13 metres and has 2 large cracks in the top.

The second crack is actually the entrance to a cave and you can drop down into this to 18m and swim through the cave to the sandy bottom.

So, as you can see, the markers that we use are fixed. There is no point using markers that can move such as; "10 minutes in you will see a big grouper"... that fish can swim away! We use big immovable rocks, tunnels, the bottom composition, depths etc. Things that remain constant day to day.

Equally, you can make use of natural phenomena, such as contours on a sandy bottom, which run parallel to shore, sun and shadows, prevailing current but your instructor or local Divers should be able to give you more information about what you can use in your area.

Don't be afraid to ask others what methods and markers they use to navigate local dive sites, we are a pretty friendly and helpful group for the most part and most divers will gladly help out.

Give it a try! Assuming you can see past the end of your nose, Natural Navigation is a great tool to use to find your way around on a dive.