currents

  • Getting Back to This World.

    When we scuba dive we enter a different world. We are privileged to see things that ordinary mortals may be totally unaware of. Leaving the shore or the deck of a boat wearing cumbersome kit to be rewarded with that instant feeling of weightlessness is just the start. We swim down and join the undersea domain of fishes and corals, and see shipwrecks and caverns and things that are hidden from those trapped at the surface. It truly is a different world and we can sometimes spend hours down there, it's so fascinating. We can also usually enjoy the tranquility afforded by the watery world below the waves.

    Surface conditions may change while you are diving..
    Alas, the time comes when the reality of decompression time or diminishing air supplies means that this wonderful experience must come to an end (before the next time). We have to rejoin the world to which we really belong - and that is when the cruel reality of life on the cusp between water and air can strike. Where is the boat? The truth is that when we submerge, for all intents and purposes we disappear from those left above. We leave the world we know and those we leave behind have little inkling of where we are. Not only that, but the the surface conditions may be nothing like the tranquility encountered below. It may have been calm when we entered the water but the wind might have strengthened and the sea-state worsened while we were away.
    100-101-2 The deployed surface-marker buoy indicates a diver is waiting below.
    It's important to let those that we depend on to make the transition from the underwater world to the world with which we are more familiar know where we are. A surface-marker buoy is the conventional answer. If you are diving in a strong current you might permanently deploy one at the end of a long line that you can adjust for depth by means of a winder reel. Otherwise you might choose to fill it with air and send it to the surface only when you decide to ascend. In that way it marks where you are while you make a shallow safety stop. Some buoys (DSMB) are open-ended while others come with a constriction at the filling end so that should a tall buoy fall over at the surface, it will not deflate. Of course, such a buoy comes with a dump-valve so that it can be deflated a rolled up after it has been used. Winder reels come in various sizes, each with a ratchet to make handling the line easier. Some divers prefer the simplicity of a spool, which, incidentally is easier to stow in a pocket when carrying it during a dive.
    Diver's Flag Surface-marker flag.
    In some parts of the world that are considered high-voltage diving destinations, places like Cocos or the Galapagos, Komodo or Aldabra, the sea can have large waves as a normal state of affairs so the boat crew will need to be familiar with the route their divers are likely to take. We underwater photographers tend to be an ill-disciplined lot and often end up in less likely spots, especially after being distracted by getting pictures of pelagic species such as whalesharks and cetaceans. We often come up where we are least expected and given that the ocean is a big place, we might need more that a brightly coloured inflatable plastic sausage. This is where the surface-marker flag is a Godsend. The surface-marker flag is deployed on an extending pole made of three sections with an elastic cord running through the centre. It is carried strapped to the diver's tank and can be deployed with one hand when it is needed. (These flags are available to purchase in the Ocean Leisure store on London's Embankment.) Because it can be positioned well above the surface of what might well be a choppy sea and because it is a bright colour in a horizontal shape, it is easily spotted. When I first tested one of these many years ago in the middle of the Pacific, not only did my own dive boat crew easily spot me at the surface, but the crew of another dive boat reported seeing it from many miles away. The other joy is that it is so low-tech. There is nothing to go wrong. Whether you choose a permanent surface-marker buoy, a late deployment surface-marker buoy or a diver's surface-marker flag, a simple brightly coloured device like this will see you safely transitioned from the wonderful underwater world safely back to your boat and the world you left behind. Some British dive boat skippers swear that a black DSMB is more easily seen (also available from the Ocean Leisure store). The choice is yours. Happy diving!Divers with DSMB get into their boat.

  • What's a Reef Hook For?

    We recently received a FaceBook message from a very happy customer to Ocean Leisure, who told us what a godsend the reef hook we had suggested was. He had called by on his way to the Sudan and equipped himself with all the underwater photography equipment he needed as well as a lot of new scuba diving equipment. As usual we asked him where he was going and on hearing that he was joining a member of the Cousteau family on a trip we suggested he took with him a reef hook.

    A Reef hook with braided line and clip.
    The water that forces itself over the deep water tongues of each reef in the Sudan can be forced to speed up just as the air over the top of an aircraft's wing has to increase its velocity resulting in often strong currents. Places like Sha'ab Rumi are famous for this phenomenon and that is what encourages the sharks. Requiem sharks need forward motion to force water through their gills in order to breathe. If they find a place with a strong current, they can relax in the flow letting the forces of nature do the work for them. It's not unique to the Sudan. Water forces its  way into the channels of the Maldives, through the passes of the Tua Motos in French Polynesia and between the islands of Indonesia as tidal differences in the ocean affect the height of the water within the lagoons of atolls of the water levels in the minor seas to the north of the Indonesian archipelago. Among many other places, Palau has some powerful current points like that at Pelelui Cut and Blue Corner too. We should not forget the diver's flavour-of-the-year, the Dampier Strait in Raja Ampat, either.
    Grey Reef Shark in the Maldives Grey Reef Shark in the Maldives
    It can make scuba diving arduous but many divers think it's worth the effort. Why? Because once you have swum down and located yourself at the point on the reef wall where the action is to be found, you merely need to cling on and watch the show. Of course, clinging on to a coral reef is to be discouraged thanks to the damage it does. Even if you were able to cling on to bare rock as one can in the waters of Cocos or the Galapagos, you'd need a strong pair of leather gloves if your hands are not to be torn. Gloves more often used by sailors are appropriate. Neoprene diving gloves get ripped to pieces within a few dives.
    Enjoying a strong current at Rangiroa in French Polynesia. Enjoying a strong current at Rangiroa in French Polynesia.
    Better still, why not avoiding touching any surface altogether? That's where the reef hook comes into its own. You simply hook in to a suitable area of rocky substrate and allow yourself to be pushed back by the flow of water. The reef hook is at the end of a length of line that is hooked to a strong part of your BC such as a suitable stainless steel D-ring. A little bit of air added to the BC gives to enough buoyancy to fly like a kite above the reef and you hover there comfortably while you watch the sharks and other fishes putting on a show.
    Flying like a kite with a reef hook to enjoy diving in a channel in the Maldives. Using a reef hook to enjoy diving in a channel in the Maldives.
    When it comes to time to go, you simply pull yourself down the comfortably braided line and unhook, not forgetting to dump that buoyancy air from your BC before you are swept back into the channel behind you or into the lee of the reef. A reef hook is an inexpensive item of kit that is stowed in a BC pocket forgotten until you need it. If you are going anywhere that currents are featured, we certainly recommend it. If you've enjoyed reading these blogs, you will enjoy reading Amazing Diving Stories by the same author.

  • Choosing the Right Pair of Fins

    There is no doubt that a good pair of fins will enhance diving performance. The problem is deciding which are the most suitable fins for you. Assuming that you select a pair that fit you comfortably, fins can be conveniently divided into three types. The super-long fins beloved of free divers will propel the user a long way down below the surface with only a couple of kicks but would be very inconvenient to use for leisure snorkelling or for normal scuba diving. They’d just get in the way. Snorkellers want fins that are lightweight to carry and can be used in combination with bare feet or neoprene swimming socks. Many have a slipper integrated with the fin. There are also some open-heel fins with straps that can be used in this way. When it comes to scuba diving, most divers want to use fins in conjunction with neoprene boots. Ocean Leisure stocks nine or ten different types of these scuba diving fins in a price range from £50 to £187 per pair. So what’s the difference? They all work but some work better than others. If you were to try them all in the placid waters of a swimming pool, you’d be hard pressed to tell the difference in their performance. However, if you are going somewhere subject to strong current such as the Dampier Strait in Raja Ampat or any of the islands of Indonesia where the tidal flow forces through between the Indian Ocean and the smaller seas to the north for example, there will be moments when you need to get you head down and go for it. It’s at such moments as this that you will find if the performance of fins you’ve got is wanting or not. There has been some confusion also about the efficacy of split-fins. This design was originally conceived by American Pete McCarthy and sold under license to various manufacturers. The first company to buy into the idea was Apollo in Japan. They made their fins from a heavy rubber compound and they were very effective but were never properly imported into the UK and they weighed a tonne. Other manufacturers bought into the idea but concentrated on making their fins as comfortable in the water as could be possible at the price of loss of propulsion. They were seductive until you really need to propel yourself forwards. This had the effect of destroying the split-fin concept and today you may still hear people insisting that split-fins are no good. This is simply not true. There are some very good split-fins and some that are not worth bag space. The Atomic split-fin is one of the most effective fins available and I have proved that with the side-by-side comparison tests of fins I made over the years for Diver Magazine. I used a specially built underwater speedometer to objectively compare different fin performances and whereas some split-fins were very disappointing, the Atomic fins were not. Atomic also makes a less expensive paddle-style fin, if you don’t believe me! AquaBionic2 Another fin that will be up to performing well when the chips are down is the Aquabionic Warp 1. The designers went back to the drawing board for this one and came up with a fin that actually alters its shape according to the load put on it. Like the Atomic split-fin it’s not cheap but it makes the most of any effort you put in. I was in Raja Ampat at a site called Mike’s Point with two young fit Germans. We turned a corner in the reef where we had the full force of the flow presented to us head-on. The two Germans never made it any further whereas I was able to get past this current-point and make it to a lee in the reef further on. Later, they said that they were impressed at the strength of my kicking but this old-age pensioner knew it was because the fins I was using made the most of my muscle power. AquaBionic If you are off to any place with high-voltage diving, whether it be the Galapagos, Cocos, Aldabra, the Maldives or any of the archipelagos further East, I really recommend you invest in a pair of fins that won’t let you down. The pain of the price is soon forgotten and all you are left with is how good they are.  

3 Item(s)