Over the last several months I have had inquiries from people who want to use my SCUBA Equipment for Recovery Dives! Some of the people who come know actually nothing about diving but they have been told that some Fishing Companies will pay very good money if Divers can just dive down and secure lost anchors to cables so that they can be recovered at a later date! How difficult can that be?
It sounds very easy really when they say that the lost item is only laying at 70 or 100 meters, that’s not too far on the surface but when underwater its a totally different thing but these people do not know any, even the basics of deep diving! All they know is that you either breath from an air hose direct from a compressor or from a SCUBA System, they do not know anything about pressure!
When you are at the surface you have 1 x Atmosphere which is the weight of the air pressing all around you so you are actually breathing in and out 1 x Atmosphere of air! A standard SCUBA Tank is charged to hold 210 Bar or Atmospheres of air which is a very high pressure of air! Now, if a diver can breath for about one hour from a SCUBA Tank while at the surface, the Pressure will increase and his air consumption will increase the deeper he dives! If he dives down to 10 meters which is 2 Bar or Atmospheres, One Bar or Atmosphere of air Pressure and one Bar or Atmosphere of water pressure then he should be able to breath for about 30 minutes on the same size tank of air! If he dives down to 20 meters, He will have one Bar or Atmosphere of air Pressure and two Bar or Atmospheres of water Pressure so he should be able to breath for about 20 minutes at that pressure! The deeper you dive, the faster you use up your air!
Now, you might be thinking why you use up your air supply faster the deeper you dive, the basic reason is your lung volume! Lets say that each of your lungs holds about one liter of air at the surface, that’s the volume of your lung capacity that must be maintained during the dive! At 10 meters deep the pressure is double what it is at the surface so you will need double the volume of air to expand your lungs normally at this depth, 2 liters per lung! At 20 meters deep the pressure is 3 times what it was on the surface so you would need 3 liters of air to expand each lung!
It sounds very odd that when you have such a high pressure tank of air that you would need more air to expand your lungs the deeper you go but basically, the pressure in the tank is good until you breath it from the tank and into your mouth and lungs, that’s when the water pressure takes over and squashes the air to the ambient water pressure which is all around you! If a diver were to hold his breath and return to the surface from 20 meters the air in his lungs would expand as he approached the surface to the 3 liters which was required to expand his lungs at 20 meters and would cause him very severe lung expansion injuries or even death! A main rule in SCUBA Diving is to keep breathing at all times and never ever hold your breath!
With Air being a mixture of about 21% Oxygen and about 79% Nitrogen this in itself under pressure can cause the body to have problems! A first problem that can effect people is called Nitrogen Narcosis, as the name suggests, at depths greater than about 30 meters you can get high and if your dive buddies do not notice your problem then it can be fatal!
Oxygen itself which is the body’s fuel is OK at lower Pressures but if you dive to around 65 meters the partial pressure will increase to a very dangerous level and can cause the diver to black out and he will probably die!
Now try to imagine that the diver manages to get down to the crazy depths to find the lost item, his air supply will be very badly depleted so his chance of returning to the surface alive would be a very poor bet!
Now I am sure that most people have heard of Decompression Sickness more commonly known as the Bends, well, this is caused by the Nitrogen in the air that you breath! Oxygen is the fuel for your body but it seems that with nitrogen you only breath it in and out and it does nothing at all for your body except create problems!
At the surface, your body is saturated with One Atmosphere of Nitrogen which causes no ill effects but as you dive deeper your body absorbs more nitrogen and becomes more saturated with it the deeper you dive! Now, the only way to expel this excess Nitrogen from your system is to breath it out, that’s the only way to get rid of it! If a diver returns to the surface without doing correct safety or decompression stops then he will have problems! If you cannot release the exexcess Nitrogen By breathing it out then what happens to it as the pressure gets less and less it will com out of a gas like state and turn into bubbles in you veins and tissues! This is like taking a bottle of soda, shaking it then removing the cover, the soda bubbles out all over the place and if this is Nitrogen in your blood stream then you have a real problem! If the bubbles get into your blood stream the bubbles can block major blood vessels. If they get into your spinal cord you could be left paralyzed and if they get into the heart or brain then its good night!
The only way to treat a diver in this condition is to give him pure Oxygen so he is not breathing in more Nitrogen that take him to the nearest Decompression Chamber which is in Cebu!
A diver who gets into the water dreaming of things that he can do after he recovers the lost item and he get well paid for his services can get into such a state of ill health even in less than one hour of the dive starting and there is a very good chance that he will never complete his task or the dive for that matter!
Some people call me bad names when I refuse to help them on these recovery projects especially when I will not lend them my equipment. Some have even said that I want to do the recovery and get the money for myself. my answer to them is to go and find the diver who went to get one item himself last december and to ask him if its worth the try, I know what his answer will be as he explains the problem from his wheelchair which he has to use full time after his bout with decompression sickness! He could not afford to go to Cebu for treatment and the owners of the item did not bother also!
Basically, if you need my SCUBA Gear to do crazy dives, do me a favor, do not bother me as I will not do business with you at all!