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Thermal Protection (part 3)

 

A warm diver is a happy diver

 

"Wetcessories" for Warmth

Last month, we used wetsuits to protect most of our body from cold water. But that leaves some key areas still exposed - our head, hands, and feet.

Keep a lid on it

Our head is a high heat loss area. Why? It has little natural insulation and, because it houses the brain (in most of us...), the body won't decrease it's blood supply like it does to our other extremities. In fact, up to 30% of our total heat loss comes from the head. So, a hood will go a long way in helping a diver to stay warm. Fortunately, using the same type of neoprene that we discussed last month, there is a bevy of wetsuit hoods to choose from.

For water that’s not too cool, you may be able to get by with a 2 or 3 mm neoprene cap which will cover the head and ears, and usually fasten with a chin strap to keep it on. But for colder water, you’ll need a full hood that covers the neck as well as the head and has a bib end that tucks into your wetsuit to minimize water flow. Depending on the water temperature, you can get a range of thicknesses from 2 mm all the way up to 7 mm.

Snug is good but...
As with the wetsuit, the hood needs to fit fairly snugly or water will flow through. However, a wetsuit hood that is too tight can cause a bigger problem known as carotid sinus reflex which can leave you with a wicked headache and even cause you
to pass out.

It can be difficult stuffing your head into a tight neoprene hood, so some makers have added a zipper along the back that you can open to get more room while putting it on and off.

The first time divers use a hood it may feel claustrophobic. So I advise getting used to your hood by wearing it in your living room or the pool before using it for an actual dive.

In or out?
And then there’s the age old question of whether you put your mask strap on the inside or the outside of the hood. As usual, there are pros and cons for each way. With your mask strap on the outside, you have to ensure that the mask skirt is under the edge of the hood. With the mask strap on the inside, you have to pull the hood back to put the mask on or off. It’s really a matter of personal preference, but outside has always seemed easier to me.

Warm hands
The next area of concern - because it effects our dexterity - is our hands. Chilly fingers just don’t work as well as warm ones. But here, you’re having to balance keeping our hands warm while still allowing them enough feeling and nimbleness to operate our equipment. So again, there are a variety of gloves you can use. For merely chilly water, you may be able to get by with a basic synthetic dive glove. But as the water gets colder, you’ll find neoprene gloves ranging from 2 mm to 7 mm thickness. Thicker is warmer but harder to move in. One added feature on better gloves is pre-curving the fingers to better fit most people’s normal hand position where the fingers are naturally curved inward when the hands are open.

 

Toasty toes
And finally, we get to our feet, because having cold feet is just not fun. Here again, neoprene booties range in thickness from 2 mm up to 7 mm, with the thicker ones being better for colder water. Important point: make sure they fit your fins! Either buy boots and fins together or take your fins with you when you try on booties. You’ll also find two heights of booties - short and tall. Short are usually a tropical weight of 2mm to 3mm while tall ones are much thicker. Both types can come in a “sock” style with no sole to a serious “shoe” type sole for walking through parking lots and on rocky shores. A thin sole is nice for just walking on a boat deck painted with non-skid paint. Another feature to consider in the tall booties is a zipper. It’s much easier to get your foot into a boot with a zipper than one without. Nicer boots also have a Velcro tab to keep the zipper from accidently sliding down during your dive.

Over or under?
And now there’s the age old booty question – do you wear them under or over your wetsuit leg? Again, personal preference and pros and cons. Under the leg is more streamlined and will help prevent the boot zipper from coming undone, but it could interfere with the seal in the wetsuit cuff. Outside the leg is less streamlined but won’t interfere with the wetsuit seal. My observation is it’s about 50-50 for the divers I’ve seen.

Are my lips blue?
For really cold water, some divers find that their lips get so numb that they have trouble holding their regulator. Devices to combat this problem include a mouthpiece with an extra-large flange outside the mouth that covers the lips by at least several millimeters, and a neoprene “ice cap” which has a strip of neoprene that fits across the upper lip like a mustache. You can also use a modified mask that covers most of your face.

 

 

Next month - diving DRY
I think that has us pretty well covered from head to toe in nice warm neoprene which will keep most people sufficiently warm in all but the coldest water. But if you really want to stay warm, especially over multiple dives in cold water, tune in next month and we’ll talk about diving dry.

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