Keeping warm – Page 3 – Learn to Dive Today Blog

Wetsuits and drysuits

Having done most of my diving in warm water I arrived in Cape Town armed with a 5 millimetre thick one piece wetsuit and a shorty to go over that, also in 5mm. This wetsuit had served me well and had done well over 700 dives. Being a custom-made suit it fits like a glove. The hoodie is attached to the shorty. I wanted it like that as I find a hood attached to the wetsuit makes my head feel spring loaded, and when turning your head it always feels like it wants to spring back.

It now has now done its time, has a few leaky holes and is fast becoming scruffy, as this photo Clare took on a dive we did on the BOS 400 demonstrates.

Neoprene also breaks down eventually, it becomes waterlogged and looses its density and insulation properties. It now feels like a 3mm wetsuit and I get cold.

So what next, a new wetsuit, or a dry suit? (Or both?!)

Drysuits

The idea of a drysuit is very appealing, aptly named, it keeps you dry and you could go for a dive dressed in your Sunday best. The right thing to wear under a drysuit is an undergarment designed for the job.

These garments are most often fleece-lined and keep you warm.

Neoprene or silicone rubber neck and wrist seals ensure no water enters the suit in these places and the boots are attached and part of the suit. A large watertight zipper opening allows you to step into the suit.

Drysuits have a few more tricks, an inflator on the chest (most often) allows you to trim your buoyancy by putting air into the suit. This also prevents the suit from squeezing you at depth.

An adjustable deflate button, sometimes several, allow you to vent air or, set correctly, will vent automatically. An extra hose is required for your first stage and a good idea is to do a course on drysuit diving before you head off to the ocean. Most drysuit suppliers will give you an orientation dive with the purchase.

We dived in the Atlantic the first time I tried a drysuit in Cape Town, a windy day with a long boat ride, 6 degrees celcius on the bottom and I was warm as toast.

Wetsuits

A decent wetsuit is also very good at keeping you warm and does not have the added buoyancy concerns of drysuits, nor does a small leak turn your dive into a freezing disaster.

Mares, a brand of dive gear, exceptional quality, not the cheapest, but most definitely one of the best, make this wetsuit. Called a Flexa 8-6-5 it has 8mm on the torso and on the upper legs and arms, 6mm on all the body joints, so your knees and elbows bend easily, and 5 mm on the rest. It has a built in back pad that give you extra padding where your BCD back plate sits against your body and very snug neck, wrist and ankle seals. I do like the front zip, but I don’t like the stiff velcro attachment on the neck and may have this removed.

The water on the first day I tested the suit was 14 degrees celcius and I did two dives back to back, spending just under an hour and a half in the water, without feeling cold at all. The subsequent dives I have done in it have been a pleasure.

I know there are a lot of very good wetsuits available and both Reef and Coral will custom make a suit perfectly, but personally I rate this suit as one of the best.

Wetting your wetsuit

There is an often repeated joke that there are two types of diver: those who pee in their wetsuits and those who lie about it. Its true to say that having just paid handsomely for a new wetsuit the idea is not to pee in it. However, sooner or later it’s going to happen to you! This is why….

The physiology

Basically, you can’t help yourself. The physiological phenomenon in question is known as immersion diuresis, a term which refers to your body’s response to being under pressure. Blood is shifted to your body’s core because of the cold and pressure on your body, which increases your blood pressure. The hypothalamus gland thinks this means your total fluid volume is too high and tells your kidneys to make urine.

What can you do to avoid immersion diuresis? Avoid diuretics like coffee and other caffeine-rich drinks before you dive! Intentionally not drinking any liquids might seem like a sensible idea, but dehydration predisposes you to decompression sickness and saps your energy.

Try to stay warm. A by-product of your body’s reaction to cold is urine. Wearing a warm chicken vest under your wetsuit may save you from having to empty your bladder while underwater. Make sure you have good gloves, thick booties and a decent hoodie. On the boat, stay out of the wind if you can, wear an anorak and a beanie or cap.

Be sober, healthy, and well rested. Some over-the-counter and prescription medications can interfere with your body’s heat conservation activities, typically by hindering the constriction of blood vessels near the skin. Antihistamines, taken for hayfever and other allergies, are particular culprits as is alcohol. Make sure you are physically fit.

How to avoid it

What can you do to prevent urination on a dive? Drink less water? The counter-intuitive answer is that you should drink more.

Deliberately dehydrating yourself, in the hope you can hold it until you surface and get out of your suit, just makes the problem worse. Because of immersion diuresis and your body’s involuntary reaction to the chilly water, chances are you’ll have to pee anyway. And dehydration makes the result stronger in odor and colour.

If you do have to pee in your wetsuit…

If you’re well-hydrated, your urine will be almost clear and nearly odourless. So it can be your little secret.

There’s no health risk to urinating in your wetsuit. If you’ve watched Survivor or read anything about treating stings from jelly fish and bluebottles, you may recall that urine is sterile, unless you already have a urinary tract infection. The worst you have to fear is a case of nappy rash if the urine stays against your skin for a long time, and this is much less of a problem when your urine is diluted.

Long Beach parking area, the divemobile, and the shower in the background

The solution is to open your wetsuit under water and rinse it between dives, if you can stand the rush of cold water. If you’re at Long Beach for a training dive, there’s a conveniently located shower in the parking area!

Keeping warm in the Cape

Cape Town water is not warm. The Atlantic ocean’s temperature ranges between 8 and 13 degrees, while False Bay can be anywhere between 10 degrees (very unusual) to 20 degrees (also rather unusual, and generally combined with visibility that can be measured in centimetres rather than metres), with an average somewhere around the 15 degree mark.

Being cold increases your risk of decompression sickness, and it makes you stupid and slow, and hence a danger to yourself and your buddy. It dimishes your enjoyment of the dive and can lead you to get out of the water when you still have plenty of air and time at your disposal.

Here are a couple of suggestions – tried and tested by Tony, a lifelong warm-water diver, and me, a boat-diving wussy…

Gear

Justin demonstrates the virtues of a good wetsuit

Ah, you say, cold water means you need a drysuit, or at least a nice thick (5mm plus a 5mm shorty on top, or otherwise at least 7mm) wetsuit to keep out the chill. This is true, but there are three other essential components to a Cape diver’s gear that can make a HUGE difference.

Booties

Get thick booties – the thickest ones you can find, especially if you have poor circulation. If you can, wear them with the cuffs inside your wetsuit.

Gloves

Gloves, at least 3mm thick, are essential. Don’t try and dive without them – you won’t be able to operate your camera or inflator hose after a while. Your fingers are not well-insulated. Again, tuck gloves into your sleeves if you can.

Hoodie

The hoodie is actually the most essential part of your gear. While it appears to be a myth that the majority of body heat is lost through your head, if it’s the only part of you that’s exposed, it WILL be the primary source of heat loss. Heat loss through the head increases with exercise up to a point, and like the hands, your head is not well insulated for the most part.

When Tony moved to Cape Town from Mozambique a year ago, he was quite resistant to wearing a hoodie, and got very, very cold (almost paralysed after a dive… not good) for the first while. He found a loose hoodie (not attached to his wetsuit) that didn’t make him feel restricted, and we are now able to do one hour dives in 12 degree water with relative ease (as long as we don’t sit around TOO much). I think this has been the greatest assistance to him in adapting to the 10 degree lower temperatures here, compared to further north.

Other techniques

A couple of other techniques that have worked for us…

Move about

If you get cold, swim a bit. We tend to stay still for longish periods, interacting with fish or taking photos or just looking, and this tends to cause one to get cold quite fast. Go for a short swim when you start getting chilled – it makes a big difference.

Wear a jacket on the boat ride

One of those cheap and nasty anoraks with a white flannel lining can transform your boat ride – specially the ride back to the slipway, after you’re wet. Put it on straight over your wetsuit. This can make a huge difference as it almost eliminates wind chill on your torso.