Scuba Diving Lesson Sitemap

Preface - In the ensuing pages, you will be exposed to many of the techniques and technicalities with which skin and scuba diving are involved. At times you will be awed, even frightened by the knowledge and skills to which you are exposed. You may, in this welter of highly specialized information, become inclined to be discouraged and chagrined.

01. Introduction - Since man first began scratching pictures upon the walls of his cave to depict his daily life, there has been a continuous record of his attempt to explore and exploit the sea. We find references to man's propensities as a diver from the time of early historic man down to the present day. Man's culture has, of course, been influenced strongly by his adventures above and below the surface of the sea.

02. Physics - Two basic laws of physics which affect a diver and are so basic as to be almost forgotten are: AIR HAS WEIGHT and PRESSURE APPLIED TO A FLUID IS TRANSMITTED EQUALLY AND UNDIMINISHED IN ALL DIRECTIONS. Let's consider these in order.

If one would picture all of the air above the surface of the earth as composed of tiny blocks of one cubic inch dimension, stacked one on top of the other up to the limits of the atmosphere, he can visualize this weight.

03. Physiology - The human body is essentially composed of liquids, solids, and natural air spaces. All of these components are of vital interest to us as divers, for although they are subjected to the same pressures, they react differently and introduce special problems by the very nature of their physical make up.

04. Descent - One of the most far reaching and oft experienced laws of physics encountered by divers is Boyles Law, which states, essentially, that under conditions of constant temperature, pressure and volume of gases are inversely proportional. This means that as you increase the pressure applied to a flexible container, the volume of that container is decreased.

05. Depth - In order to understand better some of the problems encountered at depth by a diver, it is necessary that we understand first the basic components of air, the gas we breathe.

Air is not a single gas, but is rather a combination of gases. This combination of gases is of primary importance to us, for reasons which will be explained later.

06. Ascent - As the diver begins to ascend. . . many changes begin to take place, as might be expected from what we've already discussed. It is these changes that we as divers are concerned with.

To review for a moment, Henry's Law states that the solubility of a gas in a fluid is directly proportional to pressure. We have said previously that this will cause the blood stream of a diver to absorb larger amounts of nitrogen as he descends, thus causing a condition known as Nitrogen Narcosis.

07. Open Circuit - Open circuit scuba is so called because the circuit is broken by the diver exhaling his air into the surrounding atmosphere, rather than re-breathing it.

The open circuit scubas used by sport divers consist of a tank of compressed air with a valve, a harness equipped with quick release buckles, and a regulator, which supplies air to the diver upon demand only. The basic premise of scuba is that it supplies the diver his breathing medium at ambient pressure, whatever that pressure may be.

08. Diving Safety - Safety, while extremely important underwater, is just as important to a diver above water. Many of the accidents with which divers come in contact occur either before or after the actual dive. Let's categorize the prevention of these accidents as either mechanical or behavioral, and deal with each in turn.

09. Marine Environment - What kind of things can I expect to see underwater? What are the dangers to encounter from marine life? In short, what is this underwater world like? These are some of the questions that have undoubtedly come to your mind as you have thought about diving in "live water" in the very near future. We will answer as many as we are able.

10. Resuscitation - When a person is in a condition where he is unable to breathe for himself due to drowning, electric shock, or suffocation, YOU may be able to save his life if you do the following at once. Time is of vital importance. DO NOT DELAY TO SUMMON HELP.

1. TILT THE VICTOM'S HEAD BACK, with victim on his back, neck fully extended.

11. Air Consumption - In order to calculate the time (in minutes) at a given depth, with a known volume of air, the following formula may be used:

VOLUME       
(DEPTH plus 1) x .75 equals Time in minutes.
The figure. 75 represents the consumption of air of the diver (cubic ft/minute) at the surface.

In order to calculate the remaining volume of a partially used tank, another formula may be used:
GAUGED PRESSURE OF TANK x RATED VOLUME OF TANK RATED PRESSURE OF TANK

12. Aquatic Training - The fins are used merely as an enlargement of the diver's foot, thus increasing the propelling surface. By increasing this surface, the diver is able to acquire more thrust without an equal increase in effort. There are many different types of fins on the market, and a review of their outstanding features is helpful.

A. Adjustable foot fin.

13. Diving Course - This section is for the use of those persons who wish to conduct a course in skin diving. This book should be given to every student as a text book, with reading assignments given each session. This lecture outline should be followed closely, with the instructor being sure that all of the points outlined are covered.

14. Reading - The following is a recommended list of reading all pertaining to the sport of diving. Some of the reading is instructional, some historical, some narrative; but all will be found beneficial.

Aquanauts Scuba Committee

Cayford
Clarke
Clarck
Cousteau
Cousteau & Dugan
Ciampi-Ray

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