One of the important aspects of freedive safety is taking time between dives to rest before beginning the next dive. It’s listed in our Freedive Safety Guidelines; these guidelines are the result of a collaborative effort that involved elite freedivers, spearfishers, scientists, and safety advocates in our country, including DiveWise. It is recommended a diver’s surface interval be twice his prior dive time, so if a diver spends 1:30 in down time, the surface interval should be 3:00. This is to allow the diver to offload CO2 build-up from breath-holding, and provide ample time for oxygen depleted tissues to be replenished. I’ve included a couple of examples of actual surface intervals here so you can see what this looks like in real life.
Recently, I vacationed in the Bahamas with friends and family and last night had the chance to review some video my 22-year-old son David Richardson captured on his GoPro while spearfishing. It was watching this video that prompted me to write this blog. When you watch it, notice that this video length is 3:14. He shoots a mutton (one of my favorite fish) and loses it, surfacing at 0:42. He rests at the surface for 70 seconds, 12 sec shy of twice his dive time, before heading back down to 40 ft for the same fish at 1:52, surfacing again – this time with the fish – at 3:04. His second dive was 1:12. He will rest as he casually kicks over to the boat and hands off his fish. David wears only 4 lbs of weight, weighs 190 lbs, and is very buoyant at the surface without a wetsuit. He has a very slow, calm, relaxed style in the water and is not competitive. He was the best of the three guys diving that day, but I noticed he often put the others on fish and celebrated the successes of his two buddies, who stuck together as they dived.
In the section FREEDIVING STORIES is a story by Bill Cardet who blacked out and was rescued by Sheri Daye. Let’s break down his dive and see what happened. Diving in 50 ft of water, his prior dive was a bit longer than usual at 1:50. His surface interval was a little under 3:00. His next dive was 1:30 and he exerted extra energy on the ascent in shooting a hogfish and then freeing it when it became entangled in a lobster pot line. He then had to free his shaft when it also became entangled. He surfaced and immediately blacked out and began sinking, when Sheri grabbed him and brought him back around. Bill sank after blacking out because he was overweighted. Also, Bill’s surface interval was too short by about 0:45, which is rather significant, and he exerted energy at the end of his dive which caused him to consume more oxygen than he otherwise would have. It’s hard to say which of these three issues contributed most to his blackout, but an increased surface interval could well have resulted in a successful dive.
Bill, who gave me permission to use his story, took this experience very seriously and studied it carefully. More than ever he is committed to diving with a buddy under direct and constant supervision. If he and Sheri had not been practicing one up/one down diving that day, Bill most likely would not still be with us.
My son David also experienced a very traumatic blackout at age 16 when he and his brother dived down to 90 feet together and David blacked out on the ascent at about 30 ft below the surface. His brother blacked out attempting to rescue him. They were both found at the surface, received CPR, and were medevaced under life support to the hospital where they remained in ICU and inpatient for three days. They later made a full recovery.
I point out these two examples of surface time intervals and blackout stories to encourage you to take a step back and consider your current dive practices and safety strategies. David and Bill were motivated by near-fatal events to adopt safer dive practices and they willingly share their stories so you don’t have to experience such an event.
It’s easy to become complacent, especially after experiencing so many successful dives without a problem. Yet, fatal and near-fatal stats in our sport indicate the danger of blackout is lurking and no one is exempt. You can incorporate sound freedive safety practices into your dive routine and greatly improve the odds that it won’t happen to you.
Being proactive in ensuring your own safety, and that of your dive partner, will yield a long happy and healthy life of freediving and spearfishing and a continued legacy of the same for your children and grandchildren to come.