padiscubapro:
When looking at statistics you also have to be aware that there are several versions of the tables in use, some even are doppler modified.
Right. For example the US Navy made a significant change to the table in 1984 when they went with a 30 ft/min ascent rate. As indicated above Karl Huggins applied doppler research to the US Navy tables in the early to mid 80's and developed new limits to the US Navy table to provide a safer table designed to greatly reduce the occurrence of silent bubbles. Simply stated and overly simplified, current bubble models are based on the concept that small extant bubbles from initial dives will form nuclei for more and larger bubbles on subsequent dives. The presence of silent bubbles following a significant number of US Navy table profiles, in light of currnet theory, makes that table far less than ideal for use by a recreational diver doing repetitive dives. We should also note that the the US Navy never adopted any doppler based limits and again point out that is not a surprise as they are only minimally interested in repetitive dives.
If you generate a series of repetitive dives and then work that series with a variety of tables, you will get a variety of answers as to the lenght of time allowable on the last dive or the surface interval required to allow a given bottom time on the last dive. In fact, the number of "correct" answers is probably going to exactly equal the number of tables you use. In short, dive tables are theoretical and largely a matter of faith.
So like any other theoretical approach you need to select a dive table based on a survey of what is available and careful consideration of how each one will apply to your specific needs and practices to find one that will allow you to safely do the diving that you do.
If a diver is only planning on doing one dive a day, is in good physical shape and is willing to accept a slightly elevated risk of DCS, the US Navy tables may be ideal for that particular diver. But anyone doing repetitive dives, in less than ideal physcial condition and wanting a higher margin of safety, will be far better served by another table.
In my case, I dove US Navy tables for years and while I never got a clinically significant case DCS, I also had many many dives where I did not feel particularly well even when staying well within the limits, especially after diving multiple dives per day over multiple days. Newer tables leave me feeling much better after several repetetive dives. So for me claims by a minority that the US Navy tables are safe based on their perception of a lack of research specifically indicating that US Navy tables are unsafe, has no relevence as my personal experience is a much more compelling argument.
It is a personal choice, but choose very carefully.