Assessing Whether a Dive is Safe
Posted By Ian Butler on 28 July 2000
One of the things that non-divers "know" about diving is that it is a dangerous sport. I have always disagreed with this assessment, arguing that diving is not dangerous but hazardous. The difference, within my definition, is that if hazards are correctly identified and planned for in advance they can be managed. Hazards only become dangers if they are not dealt with correctly. Obviously, while any diver can make his sport dangerous simply by not thinking about what he is doing, I like to believe that within the UK's club based training systems we teach divers to think and to stay safe.
The above, points to a need to assess dives before they take place and to ensure that the divers involved are competent to carry it out. Obviously, the level of planning required will vary according to the nature of the dive. I do not propose to go into all the ins and outs of planning a challenging dive but simply to explain the system that I use before jumping into the water. If I am acting as dive marshal I use the same approach for each diver and buddy pair as I use when making the decision to dive myself.
The simple approach I take has a maximum of four stages:
- Assess the dive (for each diver)
- Assess the individual divers
- Compare the diver ratings to the dive
- Compare the buddy pair ratings to the dive
Stages 1 and 2 simply consist of "hazard rating" the dive/diver/buddy pair, stages 3 and 4 are the decision steps, let me explain:
1. Assess the dive.
As a basically simple soul, I have an easy way to do this; count the hazards. By hazard I mean any of the following factors that applies to the dive:
- Is the dive unusually cold?
- Is it deep?
- Is the visibility bad?
- Is it going to be dark down there?
- Is there a strong current?
- Is the sea rough?
- Is the site going to present any specific hazards in the prevailing conditions?
This list is not exhaustive and the answers to these questions will vary according to the individuals involved. For instance, a dive to 30m is pretty trivial to a diver with several years' experience diving to depths of 40m+ but would be very hazardous for a novice on his first sea dive. One divers idea of bad visibility may also vary immensely from another's and good visibility at one site may be quite unacceptable at another, this also needs to be allowed for when rating dives. (If you are wondering why the definition of good / bad visibility changes from site to site consider diving a wreck like the Dakotian in Milford Haven. This is a large cargo ship lying upright in about 20m; the holds have large, open, deck hatches. In good visibility it is very interesting to drop into the holds for a poke around but in poor visibility it can be even more interesting if you begin your ascent and discover a roof in your way because you have unknowingly worked your way into a hold!).
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