Everybody’s first dive will forge its individual experience deep into the memory bank of that diver. The interesting thing I have realized was that many of those who learn and master cold water diving (perhaps with years of dives) have anxiety for diving in warm water. While the same goes for warm water divers who are reluctant about putting on those layers and added weight and who usually avoid the cold temperatures all together.
So, let’s deep dive into some of the differences of cold and warm water diving, and find what what you need to consider when preparing for cold water diving.
First, Why the Anxiety?
Like changing jobs, many people feel as if they are going to have to start from scratch and be new all over again. Well, hate to break it to you. That’s exactly what is going to happen when changing from diving in cold water to warm water, and vice versa.
It’s time to get off that high horse and add a bit of humility because you may find that a diver with 30 dives in the environment you’re venturing into is much more comfortable than you, with perhaps hundreds of dives in the alternative. It may only take a few dives to figure it out but you still need to forget a bit of what you know and alter it for the environment you’re now in.
I’ll sweat to death!
Yep, number one on a cold water diver’s concern is that they layer up so much and are comfortable in 6°C/43°F or less water, that they fear they’ll die of heat exhaustion in anything above 20°C/68°F!
One thing to remember is that water conducts heat away from your body 20 times faster than air. So, as you increase your exposure to the water by reducing your thermal protection to possibly only a rash guard then the longer you are in the water you will likely not overheat. You may even become cold in 29°C/84°F after 40 minutes of diving. So start with what is recommended by the local dive professional and see how you feel at the beginning, during and after your dive and change it accordingly.
Read More: How Does a Drysuit Work?
It’s too damn cold for me!
Yep, cold water is cold. Otherwise it wouldn’t be called “cold water diving”. Typically, it means anything below 14°C/75°F (Note: Cold water regulator distinction is rated to EN250 EU standard for anything below 10°C/50°F that could have more potential for a free-flow at depth).
But with the proper planning in thermal protection you will be able to enjoy any temperature you plunge into. Now let’s talk head to toe about the thermal gear going from warm into cold because, yeah, this is the big difference there.
Cold Water Diving Gear
Cold Water Diving Hoods
You lose the majority of your heat from your head, likely because of all that thinking you do. So in warmer waters it may be optional but in cold water a hood is mandatory. You forget your hood, you ain’t diving.
Correct fit is important as to keep the trapped water tight to your skin and all that brain activated heat keeping you warm. If your hood doesn’t fit correctly or the upper skirt of your mask isn’t covered by the hood properly you may end up with what can only be described as an “ice cream headache”. Not fun and it could last for hours after the dive. So make sure to have that sorted before you take your gear to the open water.
Your scuba diving mask is as important as any gear in your kit. Aside from the obvious benefits and necessity of having a mask I’m just going to explain a bit of how to prep your mask. Make sure it fits. A good seal is more important than the brand. You could have the sexiest and most expensive mask ever made but if it don’t fit it ain’t gonna work for you. Next, would be how to prevent the mask fogging.
Masks fog up when the temperature inside the mask is significantly different to the temperature outside of the mask. For example; your warm breath against the cold glass.
Initially, when you buy your mask from your local dive shop each mask is conditioned with a protective coating by the manufacturer. You’ll need to remove this otherwise it will fog up constantly. So prepare your mask the night before your dive. What you need is basic white toothpaste (not gel) and baking soda. Mix these two ingredients and rub that mixture with your finger to spread it on the inside lens of the mask. Then wash it out prior to your dive.
Read More: Pro Tips to Stop Your Mask Fogging Up!
Our recommendation before every dive is to treat the mask with anti-fog or good ole fashioned spit on the inside of your mask. Leave this ‘goo’ until the last moment that you put the mask on.
In cold water you will want to plunge your face into the water you’ll be diving in to get it close to the temperature of the water. BRRRR. Then rinse out that goo with the water you’ll be diving in.
Finally, put the mask on and make sure there’s no forehead exposed and the hood covers that top skirt of the mask. Additionally, don’t over-tighten that mask with the strap. The mask is meant to fit with a good seal. So if fitted properly it will vacuum onto your face on its own. The strap is there to hold it on and not to tighten the mask to your face.
Cold Water Scuba Diving Regulator
One thing to consider when venturing into the cold is “Will my regulator be safe?”
A regulator you bought at a resort in the tropics likely won’t cut it when plunging into the cold water. Why? Because, chances are they’re unbalanced and not environmentally sealed.
This means the regulator can breathe hard at depth (like sucking through a long straw) or even worse, freeze up and free-flow if you end up in waters that a polar bear frolics in for fun. I would strongly suggest not skimping out on a “cheap” regulator when purchasing. Even if you don’t plan to ever dive in the cold; you never know what lies in your diving adventures and you don’t want to have to fork out that dough again if you can prevent it.
Consider buying a cold water diving regulator that is balanced and sealed. Remember, this is your life support system. A hardy regulator made for cold water diving will be versatile (and safe) for diving in both cold waters and warm waters. Be sure you have a good one from the start and service it as the manufacturer recommends to keep it well maintained. So buying a reg that can withstand harsher conditions will most certainly be fine in any condition the tropics will present. They make regs like this that are light-weight, relatively inexpensive and pretty much “bulletproof” to most conditions.
Drysuits and Wetsuits
With cold water diving, you will certainly need a warm exposure suit. If the temperatures are going below 14°C/57°F you should look into a 7mm neoprene wetsuit, a semi-dry neoprene wetsuit or a drysuit (neoprene or membrane).
Neoprene adds buoyancy so that will also decide how much weight to use (We’ll talk about this later). The difference between a wetsuit and a semi-dry are mainly the seals and the zipper. While both require water to flood the suit (Note: the initial flood does suck in the cold) neoprene is incredible for not allowing water to penetrate through it. It’s essentially engineered closed-celled rubber. The water enters through the seals, usually with your help, and does not seep in or out through the neoprene, as many assume that that’s how water enters the suit. Meaning it traps the water from circulating and your body heat keeps that trapped water warm. So the seals of the semi-dry should be tight and snug and the suit should be as close to your body to heat up as little water as possible. So make sure the thing fits you like “Flanders’ ski suit” and could make you bashful in the company of others.
A proper semi-dry has a similar zipper to a drysuit where it allows zero water seepage when secured. The drysuit zipper uses the same technology as an astronauts suit zipper and makes it air tight.
A wetsuit does not have this “air tight” mechanism and can allow some water transfer that may cool you down over a dive.
Drysuits basically trap air into the suit via an inflator hose keeping you nice and dry and toasty. Though you should take note that you’re still submerged underwater for a good period of time so a drysuit isn’t 100% dry. Contributors to getting wet inside your suit are sweat, warm body temperature colliding with the cold water temperature outside may cause condensation or you may move in your seals like looking around with your neck instead of your body allowing water to trickle in. Or worst case you get a tear in your seal or a puncture in your suit (Also note: you should seek training in order to safely and effectively use a drysuit).
A neoprene drysuit adds thermal protection but still adds buoyancy whereas in a membrane drysuit it’s only the underwear you are required to wear that keeps you warm that may add to the buoyancy. A membrane drysuit gives you zero thermal protection. Basically it’s a fashionable garbage bag.
Same as a hood. Don’t have gloves? Then you ain’t diving in the cold, my friend. They can be wet or dry but I personally enjoy a dry glove with a nice thermal liner. In wet gloves your hands may get numb after a long dive in the cold even if they fit like a “glove.” The thicker the glove the more difficult it is to move your fingers, however. If using a 7mm glove or thicker you should opt for “lobster” 3-fingered gloves for better dexterity in a wet glove.
Diving Booties and Boots
Booties are great with a wetsuit but boots are required on a drysuit. Booties give you the same thermal protection as a wetsuit so it’s good to have fitting un-holey ones. They range from 2mm-7mm and you should purchase them accordingly based on the type of diving you’ll be doing.
Diving boots are designed to either go over neoprene socks attached to a drysuit or the boots themselves are attached to the drysuit In a bootie they can typically be used with any of your warm water fins. A boot will be larger and require a larger fin size to fit them.
As stated above, booties vs boots require a different sized fin. So if you wear a medium fin (9-11US/42-45Uk) you may need to buy or rent a fin size of XXL to fit your boots.
Fins are always subjective as far as style but I prefer more robust and sturdy fins for cold water because you make less movements in the additional gear and weight you require in these waters.
Cold Water Diving Weights
Ok, now let’s talk about weight. The point of diving is to be submerged underwater for a good period of time. You need to stay down. How much weight you need for this is determined by what you are wearing. In warm water you may only have a 2mm vest or a rash guard or simply “nothing at all” where 4-6lbs/ 2-3kgs will be sufficient.
In cold water diving, you could be wearing 7mm neoprene or more which could bring that amount to nearly 50lbs/22kgs. So how you add weight is crucial by using a weight belt, a heavier steel tank vs aluminum, a weighted standard tank adapter, trim pockets or most people will use their integrated weights on your bcd. Weighting and the positioning of the weight will change as you configure your gear to the type of diving you do.
Try our Scuba Diving Weight Calculator to figure out how much weight you should use!
Buoyancy Compensating Device (BCD)
This, like all the points above, could be a long topic but I’m just gonna keep it simple.
In warm water pretty much any BCD will do. Jacket, wing or backplate with no real consideration than to what you prefer.
However, in cold water the same applies but you now have to take into account your bcd or wing’s lift capacity. With as much as 50lbs/22kgs you may need to use a different bcd you wear in warm water to accomodate all that lead weight.
As well, things need to be more streamlined and positioned deliberately because you have less mobility and possibly big thick gloves that may make it difficult to reach something you could do with ease and without thinking in the warm.
Plan Your Dive, Dive Your Plan
Like sex or pizza there is never a bad dive! Just be sure that you prepare accordingly and can adapt to unforeseen circumstances with the proper training. So venture out. Explore to your heart’s content. Become experienced in both warm waters and cold waters and then you can go anywhere without anxiety. Be a diver that will be prepared, trained and able to plunge into the depths regardless of what temperature you may be plunging into. And most importantly, have fun out there.