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About this tool
Score your pre-swim checks on water temperature, tow float, buddy and exit plan before an open water swim.
This checklist scores your open water pre-swim preparation across fifteen checks — buddy, tow float, conditions, exit plan and turnaround rule — weighting safety-critical items double so a missing one blocks a pass. It reads your water temperature against the World Aquatics open water limits (racing between 16 °C and 31 °C, wetsuits compulsory below 18 °C and not allowed above 20 °C) and against the 1-10-1 cold water immersion principle. It is informational preparation support, not a substitute for a lifeguard or a venue risk assessment.
Open Open Water Swim Safety Checklist on AltFTool — it loads instantly in your browser.
Add your input to the workspace.
Adjust the options until the result looks right.
Copy or download the output and put it to work.
Missing a buddy, tow float or exit plan returns 'not ready' no matter how many other boxes are ticked.
Bands are tied to the 16–31 °C competition range and the 18 °C / 20 °C wetsuit thresholds.
Copy the summary into a group chat so your shore contact knows the plan and the return time.
Open water competition under World Aquatics rules does not run below 16 °C, and below 15 °C the cold shock response is strong enough that unacclimatised swimmers lose breathing control in the first minute. Cold water swimming below that is done by acclimatised swimmers with short exposures, supervision and a warm change plan.
It describes what happens after sudden cold water immersion: roughly 1 minute to get the gasp reflex and breathing under control, about 10 minutes of meaningful movement before hands and arms stop working, and roughly 1 hour before hypothermia causes unconsciousness. The practical message is that the first minute, not hypothermia, is what drowns most people.
A widely used open water club rule of thumb for unacclimatised swimmers without a wetsuit is about as many minutes as the water temperature reads in degrees Celsius — so roughly 12 minutes at 12 °C. Build up over repeated swims rather than in one session, and get out while you still feel fine.
A tow float does not keep you afloat by itself, but it makes you visible to boats and paddlers and gives you something to hold if you need to stop and rest. Strong swimmers are still invisible in chop, and visibility is the check most often skipped in incident reports.