Layering: does 3mm + 2mm = 5mm of warmth?

[youngjun]

When layering wetsuits, does a 3mm fullsuit + a 2mm vest or shorty have the same insulating value as a 5mm (in those layers where the material is doubled)? Or does a 3mm farmer john + 3mm jacket give you the equivalent warmth of 6mm around the torso and upper legs? (You get the idea). Or would a straight 5 or 6.5mm fullsuit be warmer? I'm seeing if I can buy one or two pieces that will be versatile in a variety of different temperatures.

 

[TexasMike]

While I don't have any "scientific" data that saying that layering 3 mil over a 3 mil is equal to a non-layered 6-mil worth of neoprene, I can say that when I add my 2mil hooded sleeveless vest to my full body 5/4/3 suit, I do find that I can stand colder water temps than when I am just in the full body suit.

So the answer to "does layering work like ski or hiking clothes" is a yes from me.

 

[Ari]

Although not all materials are equal to begin with.

Some resist compression more and will stay warmer in depth. Some are better quality than others.

As a thumb rule, layering is a great way to be flexible and adapt to cahnging water temperatures and diving conditions.

Ari

 

[youngjun]

OK, on a related note... (1) I'm thinking about getting a 5mm full suit. Do you think that plus a 3mm shorty will give me enough insulation for 50-55 deg F?

(2) Or can you even layer a 3mm full suit over a 5mm full suit and have that give me enough insulation in the aforementioned temperatures.

Basically, if you can read between the lines, I'm trying to find the best wetsuit combination for all my diving destinations which includes the SE Asian Tropics to beneath the thermocline in the Chicagoland lakes.

 

[scuberd]

I'd imagine that wetsuits work in the same principle that jackets work. 2mm + 3mm = >5mm

more water is trapped and warmed with the layers than if it was one piece. kind of the double panned window theory.

After growing up in the mountains, I know this works well with things like snow jackets and I am assuming its about the same with wetsuits

 

[Grunt]

Originally posted by youngjun
OK, on a related note... (1) I'm thinking about getting a 5mm full suit. Do you think that plus a 3mm shorty will give me enough insulation for 50-55 deg F?

(2) Or can you even layer a 3mm full suit over a 5mm full suit and have that give me enough insulation in the aforementioned temperatures.

Basically, if you can read between the lines, I'm trying to find the best wetsuit combination for all my diving destinations which includes the SE Asian Tropics to beneath the thermocline in the Chicagoland lakes.

(1) I'd say definitely not - in fact I would probably refuse to buddy someone who dived with a 3mm shorty in 50 deg water as I'd be worried I'd have to be dealing with their hypothermia. I'm sure there are some tough people who can take it, but that's pretty extreme.

(2) I saw someone put a 3mm over a 3mm and dive in 50 deg water and say he felt okay.

In your situation I would say that two cheap suits of the right insulation is better than trying to get one better quality suit that is not really appropriate for any of your dive conditions.

For 50 deg water I would go with a two piece farmer john 6.5 - 7 mm (I use a 6.5).

For warm water I would use a full 3mm, not so much for warmth but more for protection from stings and stuff - I'll have gloves too.

I got two suits for about $300, which is not cheap, but at least I have the right equipment for different situations, rather than trying to make do which can spoil your fun.

 

[Grunt]

Originally posted by scuberd
I'd imagine that wetsuits work in the same principle that jackets work. 2mm + 3mm = >5mm

more water is trapped and warmed with the layers than if it was one piece. kind of the double panned window theory.

You'd think so, but that's not actually how it works. What keeps you warm is the bubbles in the neoprene, not the layer of water (which is so conductive to heat that it cannot act as an insulator like air in a window).

2mm+3mm means more neoprene = more bubbles in it to insulate. However, you will tend to lose some of the benefit because with two layers you will probably have more water going through which will steal heat.

So in theory anyway 2+3<5 in this case - not by much but a little.

 

[youngjun]

quote...
(1) I'd say definitely not - in fact I would probably refuse to buddy someone who dived with a 3mm shorty in 50 deg water as I'd be worried I'd have to be dealing with their hypothermia. I'm sure there are some tough people who can take it, but that's pretty extreme.

I totally agree! But I think you misread. I meant 5mm fullsuit + 3mm shorty for 50 deg water. So you'll have something less than 8mm around what I would think are the critical areas and 5mm towards the ends of your appendages.

But maybe you're right, I should just get the 2 kinds of suits you recommend.

 

[Grunt]

Originally posted by youngjun
I meant 5mm fullsuit + 3mm shorty for 50 deg water.

Doh!

Ok then - let's dive.

 

[TexasMike]

Originally posted by scuberd
more water is trapped and warmed with the layers than if it was one piece. kind of the double panned window theory.

A correction is needed here....

It is not the water that helps with insulation...it's the small bubbles of air in neoprene.

Remember, water transmits heat MUCH MUCH faster than air, so any water in contact with your body will pull heat away from you very fast, causing you to be chilled. This is why you can sit in an 85&degF bathtub and still get chilled after enough exposure time.

Youngjun...if you are looking something to go between to two dive areas you mentioned (Asia and Chicago), then you might start researching drysuits. The right drysuit is perfect for the colder waters of the American North, and the tropical waters of Asia. All you change is the amount of "underwear".

Yes, they are more expensive, and do require more skills to manage than a wetsuit, but you definitely will get loads of comfort out of the equation.

--TM