DSMB

  • Five Ideas to Improve Your Diving.

    Get Your Trim Right . Often, divers carry the right amount of weight but in the wrong place. A drysuit diver needs to carry the best part of his weight in such a manner that his chest will come up slightly and his feet go down. Consider where the fulcrum or pivoting point of your body will be. Integrated weight pockets on a BC might be too high up on a long-legged diver.  A weight harness allows weights to be slung lower. On the other hand, a diver wearing a lightweight suit and using an aluminium tank might need to add some weight higher up and, if the BC in use has no trim-weight pockets, you can always add a couple of kilos to the camband that goes round the tank. You need to be comfortably horizontal in the water without any tendency to invert.Trim Deploy a Delayed Surface-Marker Buoy Easily in Mid-water. Why do so many divers make a mess of this? Is it because they haven’t been shown how to do it? Carrying a big camera? Learn how to do it easily with one free hand. Stream the buoy so that it floats above you. A tiny bit of exhaled air in it will help keep it up. Pull off as many metres of line that is practical, so that your reel hangs below you. Take the open end of the buoy and hold it with fingers and thumb above the upper side of the exhaust-T of your regulator while holding your head a little to one side. Have the line passing through but not gripped by your hand. Exhale into the buoy. It will start to ascend. Exhale again immediately releasing your grip on the buoy and grab the reel as it gets pulled up to your hand. Release the line from the ratchet of the reel. Watch the buoy go. Tighten off the ratchet as soon as the line loses its tension because the buoy will have reached the surface. Get Your Weight Right. The human body is more or less neutrally buoyant. Take a big breath and your float. Empty your lungs and your heavy head will go under. If we didn’t wear buoyant kit such as our suits, we wouldn’t need to wear weights. If you want to get your weight right, exhale hard at the surface and the weight of your head in the air should push you down. Add an extra amount of lead to compensate for the weight of the gas you might exhale out into the water during the dive and you’re perfectly weighted. So why do so many divers wear too much weight? Is it because they are used to plummeting to the seabed and trampling around before putting air into their BC of suit to make it back to the surface? Neutral buoyancy is the very essence of pleasurable diving. If you are neutrally buoyant near the surface in your drysuit, you will only need to add sufficient air during the dive to make up for the compression of the air that was in it when you started. If you need to put air in your BC too, there’s a good chance you’ve overdone it with the amount of lead you are carrying. Use Your Lung Volume. Don’t keep fiddling with your BC direct-feed inflation. If you are using conventional open-circuit scuba, varying your lung volume can be a useful adjustment when heading over or under obstacles. A big deep breath will stop you from crashing down lower than you intended and using the range at the other end of the lung-volumes you have available will enable you to cruise over things without inadvertently heading for the surface. You’ll soon find that you can do this almost unconsciously and it’s a great way enjoy a relaxed dive. You’ll also find it helps to keep station at a blue water safety stop. Wear a Suit That Fits. When someone asked me which was my favourite diving suit, I replied it was the one that fitted me best. If your drysuit fits your perfectly, there will be less of a drag when you are swimming. If your wetsuit or semi-dry is too big, cold water will flush around it under the arms and around the groin so that you’ll soon feel cold. If your drysuit is too small you either won’t be able to sit down in it or you’ll be limited to the choice of the undergarment you can wear with it. If your wetsuit or semi-dry is too small, it might interfere with your ability to breathe. Try a suit on before you buy it. That's what the changing rooms at Ocean Leisure are for! We're there to help you.

  • 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.

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