hi,
i've been diving for 15-20 years now and i'd really reccomend that you know how to swim and be reasonably comfortable in the water before learning to scuba dive. if nothing ever goes wrong, you could probably get by not knowing how to swim well, but eventually something goes wrong and you will need those skills. if you are diving in cold water (like monterrey, california), you usually have a 7mm wetsuit, hood, booties, etc so you are really bouyant. typically i've got a 25 lb weightbelt to counteract that bouyancy. under most emergency conditions you could just drop the weightbelt and you would be on the surface and couldnt sink (exhale while ascending) but there is a lot of kelp (long seaweed) big waves, surge, etc. just natural open water processes that you need to know how to swim to deal with. this also applies when doing warm water diving.
going into the water, especially open ocean water while not knowing how to swim is really not a good idea. dont do it, learn to swim first.
how dangerous a sport is this? here's a cut and paste with the statistics... about twice as dangerous as driving.
> Dive Fatalities Per Year 91.2 91.2 Note (1)
> Certified Divers 9,500 9,300 (thousands) Note
(2)
> Active Diver Percentage 33% 25%
> Active Divers 3,135 2,325 (thousands)
> Avg Dives/Yr per Active Diver 10 6 Note (3)
> Avg Dives/Yr per Certified Diver 3.30 1.50
> Hours/Dive 0.75 0.75
> Diving Hours Per Year 23,513 10,463 (thousands)
> Diving Hours Per Fatality 258 115 (thousands)
> Diving Yrs/Fatality,Active Divers 34 25 (thousands)
>
> DRiving Fatalities Per Year 43,500 41,200 Note (4)
> DRiver/Rider Population 311 200 (millions), Note (5)
> DRiving Hours/Day Per Driver 1.5 0.5
> DRiving Hours Per Year 170.3 36.5 (billions)
> DRiving Hours Per Fatality 3,914 886 (thousands)
> DRiving Years Per Fatality 7.1 4.9 (thousands)
>
> Hourly Risk of Dying:
> Diving/DRiving 15.2 7.7
> Annual Risk of Dying: Diving/DRiving 0.21 0.19
>
> Notes:
> (1) Average yearly fatalities reported by DAN for last 10 years (North
> American divers: U.S.+Canada). Note that there has been a reassuring
> downward trend in diving fatalities over the decade, so 91 may be slightly
> high if recent trends continue.
> (2) Per PADI: 8.5M cert US divers (all agencies, including NAUI, SSI,
etc);
> Dan assumed an additional 1M Canadian divers, John 0.8M.
> (3) Dan: best guess. John: assumes a distribution of 20, 5, 3, 1.5 & 0.5
> average dives/year for six guesstimated active 5 percentiles of total
> certified divers (remaining percentiles assumed inactive).
> (4) Dan used 1998 National Safety Council statistic, John used 2000
> Almanac, which listed 1998 traffic fatalities.
> (5) Dan assumed 280M US & 31M Canadian drivers/riders; John guessed 200M
> drivers & car occupants based on 273 M US (1999), of which 70M are under
> age 18 and 35M are over age 65.
