Pre-Dive Checklist
Before every dive, run through these steps on your computer. Five minutes on the surface prevents confusion at depth.
Check battery level. A low-battery warning before a deep dive is not where you want to discover you forgot to charge. Verify sufficient charge for the planned dive plus safety margin.
Set gas mix. If diving nitrox, analyze your tank and enter the exact O2 percentage. Verify the displayed MOD matches your expectations. If diving air, confirm the computer is set to 21% O2.
Verify units and settings. Confirm metric or imperial, conservatism settings, and alarm thresholds are set to your preference.
Check surface interval and residual nitrogen. If this is a repetitive dive, review your surface interval timer and tissue loading. Plan the next dive within the limits your residual nitrogen allows.
Plan mode (if available). Many computers have a dive planner or simulator mode that lets you enter a planned depth and shows the estimated NDL before you splash. Use this to confirm your dive plan is realistic.
Managing Your Dive
Dive your deepest point first. Descend to your maximum planned depth early, then gradually work shallower. This maximizes your NDL because you spend the most time at lower nitrogen-absorption rates.
Monitor NDL continuously. Glance at your screen every 2–3 minutes. Note how fast NDL is counting down — if it is dropping rapidly, you are absorbing nitrogen quickly and should plan to ascend soon.
Begin ascent with NDL margin. Start your ascent with at least 5–10 minutes of NDL remaining. This gives you buffer for a slow ascent, safety stop, and any unexpected delays.
Respect ascent rate warnings. Ascend at 9–10 m/min or slower. If your computer alarms, slow down immediately. The last 10 meters is where slow ascent matters most.
Complete the safety stop. Hold at 5 meters for three minutes as your computer counts down. Use this time to look up at the surface, check for boats, and prepare for a calm exit.
Planning Multiple Dives
Deepest dive first. On a multi-dive day, do your deepest dive first when your tissues are cleanest. Make each successive dive shallower.
Allow adequate surface intervals. A minimum surface interval of one hour is standard. Longer is better, especially before deep or demanding second dives. Your computer shows the surface interval timer and desaturation time — use them.
Do not exceed three dives per day. Training agencies generally recommend no more than three dives per day for recreational diving. Each additional dive accumulates more residual nitrogen and reduces your NDL.
Stay hydrated. Dehydration is a DCS risk factor. Drink water between dives — not just on the first surface interval.
Post-Dive Logging
After every dive, your computer stores a profile in its internal logbook. Sync to your companion app (Shearwater Cloud, Garmin Dive, Suunto App, Cressi LogBook) while the data is fresh. Review your depth profile, max depth, NDL cushion at turnaround, ascent rate, and air consumption. Over time, your dive log becomes a valuable record of your development as a diver and helps you plan future dives more accurately.