The waters around Vancouver can be as warm as 20+ degrees Celsius. Unfortunately it is only the top five to ten meters of water that are this warm. Below that surface layer, which only exists in summer, it is a balmy 5 – 8 degrees Celsius (that’s about 40 degrees Fahrenheit). In other places in BC, there is no warm surface layer. BC properly qualifies as cold-water freediving. Because of the cold, BC divers are usually not in the water for more than 50 minutes in the winter, or two hours in the summer.
One of my first dives was at Porteau Cove with @toddkabaluk. I think this was in early February, 2014 (write up here). We were in the water for about 50 minutes. Tkaba was rocking the cold with a 3 mm suit and an extra 3 mm vest and I was in my old surf suit 9 mm on the core, 4.5 on the limbs). When we got out of the water we drove back to Vancouver with the heater in the car blasting. I spent the rest of the day having dinner sized meals in between naps. I don’t think I have ever eaten more in a single day apart from maybe the day after one of my 20 hour orienteering races. The cold is a force to reckon with.
Countering the cold with proper freediving gear
There are a few ways to manage the cold, but all solutions of course are temporary. The first thing to do is to make sure you are using an adequate wetsuit, at least 5 mm in winter, including warm booties and gloves (or mittens). Divers who want to have one suit to dive in year-round will often choose a 5 mm wetsuit. These can be bought with waist high pants or long john pants. The benefit of a long john is that you get twice the thickness on your chest and back and you can keep your core warmer that way. If you are not that good with cold or you want to maximize your winter dive-time you can get wetsuits as thick as 7.5 mm. I wear a 5 mm suit with waist high pants, and a 3 mm sleeveless vest underneath.
Keep in mind that every extra bit of neoprene you wear will be balanced with extra weights. If you are a natural floater, you are going to have a lot of weight on you if you are in a 7.5 mm suit. Remember also, that the suit compresses at depth and becomes negatively buoyant. If you are diving with a thick suit and a lot of weight you have to work hard to come back to the surface. Always be careful and mindful when diving with new gear.
There’s a freediving fin for every season
I used a pair of plastic cressi gara 3000 fins until a few months ago. Because I am a natural sinker and I have heavy legs, I always kicked. When I switched to an Orca Dol-Fin I found out that that kicking kept me warm. The Orca Dol-fin I use was originally owned by Eric Fattah (see his review on the Orca here) and he added 2 pounds of incompressible buoyancy to the fin. My bottom time with the Dol-Fin is longer, and my dives are more relaxed, but my total dive-time has decreased because I get cold faster. If I want to do shallower dives and stay in the water longer, I have to resort to my plastic flaps. Line-diving and depth training is a no-go in winter.
What to eat before freediving
Food and freediving is tricky. When you are in very cold water your basal metabolic rate needs to go up so that you can produce extra heat. What better way to burn off energy than burning sugars? They are easy to replenish (Gatorade or any other type of sugary drink will do) and easy to burn (they are dissolved in your blood stream instantly). There is of course a downside to this too. Digestion requires oxygen, and if you normally on a low sugar diet you will get a sugar high that will make it harder to dive.
I like diving on an empty stomach best. I usually do not eat before freediving in summer, but if I don’t have any energy readily available in winter I’ll be cold as soon as I get in the water. What is the right thing to do? Freeze, dive with a (half-) full gut, or keep a bottle of Gatorade in the dive float?
Other tips for keeping warm that I have heard but not tried:
- Stuffing your wetsuit with heating pads
- Keeping your wetsuit in an eski with warm water before diving (at the very least it helps being warm right at the start of your dive!)
- Keeping warm weak tea in your float