Every diver of every category of diving has heard the same mantra over, and over and over again. “Plan the Dive, Dive the Plan.”; while essential for scientific and commercial dives, it’s often a little looser in application on the recreational side. More so when you dive with a computer instead of using the more restrictive tables provided by diving organizations. This post will be on some good habits, alternate tables and good planning techniques that will help bring you back to the boat or the shore for another dive!
Dive planning doesn’t have to be a painful process or a cumbersome pause before a dive. A simple plan could be: “Swim out 50m to the cliffside, descend to a maximum depth of 20m, follow the wall out until we hit about a third of a tank or 30 minutes, come back”. No protracted descriptions, no overwhelming info, just a bare bones, functional plan. You could add in hazards if there were any, and do a time check or something, but this is a good basic plan. Further things could include shooting a bearing back to shore in case of separation or even testing emergency gear. Virtually any plan is better than no plan.
I like to break the actual dive planning into four sections: divers, the dive, potential and known risks and emergency planning. Divers is the most challenging part, especially if you have a mixed bag of skill and comfort levels. This is a very normal occurrence. Pay attention to who you have, and be ready to prepared to change things based on what they are ready to deal with in both your and their opinion. The dive is the easy part; depth, time, direction of travel, direction of return. Known and potential risks is a bit more challenging; tide, current, weather, marine life, overhead environments, entanglement risks, low visibility, temperature… all can be present, or none! Read up on your dive location, talk to local divers and if you can, take an experienced buddy or even a guide out and recce it before bringing your group. Be ready to abort if conditions are bad. Emergency planning gets hard when you’re going to a remote location or a difficult-to-get-to location. In both situations, communications are key, as is good first aid training. The biggest thing you need to plan for in both situations is how you will evacuate an injured diver to medical attention. Plan for the best, but hope for the best!
Planning for depth is vitally important, regardless of if you dive a computer or by tables. In my diving life, I have used PADI, DCIEM and NOAA tables in addition to my computer for dives. I love my computer, a Suunto D4, but I still refer to tables on a regular basis. Why? Well, for scientific dives and commercial dives you cannot use a computer (literally, it’s prohibited by both CAUS and WCB). Many computers are too lenient when it comes to residual nitrogen, and can be “bent”, an unacceptable risk to professional divers diving on a regular/continuous basis. Personally, I always have my tables in my dive bag, in case my computer fails, or in case I forget the thing on the kitchen table. Diving on a computer is safe and reliable for recreational diving, just be sure you know how to operate it and avoid pushing it to the limit.
On the subject of tables, I have a preference for NOAA or the very similar NAUI tables, for their relative ease of use (no math required, highly intuitive, metric and imperial measurements). DCIEM is the best for cold water work though, but definitely requires some type of formal training to use them properly. Remember, if you’re going to use tables that you haven’t been trained on, read up on them and their use before putting them into service in the field. Tables are great for getting a quick idea of bottom time to, particularly if you’re diving with a wide variation of computers or if someone forgets theirs! Dive tables are viewed as antiquated by by many divers now that computers are nearly ubiquitous. They’re excellent for planning dives though, and are ideal as backup in case of computer failure.
Overall, dive planning for recreational dives is a very simple business that can be done by just about anyone. I’ve outlined the basics for a typical dive; wreck, deep, night and other activities are things that require more preparation and in some cases, and formal training in others. The biggest thing to take from all this is that as a diver, plan and conduct your dives within your own limits of comfort, experience and training. Plan the Dive, Dive the Plan.