Question Help Me Settle a Bet . . . with My Wife

[rx7diver]

You might try a thicker hood as a first step.

(But she's still right, and you're wrong.)

rx7diver

 

[inquis]

If you just add air, it will just migrate above you. Your front will be just as cold (assuming undergarments are fully lofted in both cases).

 

[Brett Hatch]

It depends on how tight your suit is when you're at depth. If you're diving shrink-wrapped, then you can afford to add a few squirts of air, which will be warmer. I'd say give it a shot. But, if you add enough air to make a moving bubble, you'll be a little warmer, but it's not really a good trade because managing the bubble is a PITA. If you're ever diving and find yourself really cold, it's better to have a bubble floating around than it is to be cold, but, planning it this way is not a great plan.

If you're using wet gloves, thicker wet gloves will be warmer, and drygloves will be much warmer.

If you're using no hood, a hood would be warmer, or a thicker hood.

You can also try a thicker base layer, or adding on additional base layers. I like merino wool for this purpose, its stretchiness makes it easy to layer 2 or 3 of them.

A higher loft undersuit would be warmer as well, but is more expensive than all of the above. A heated vest is warmer still, but they run about a thousand dollars.

In Monterey, the water is typically around 9-10C / 48-52F. It's not uncommon to see drysuit divers with thick undies, drygloves, and a thick neoprene hood (like up to 12mm). And you'll sometimes see people in a 7mm with no hood and no gloves, so YMMV. I don't see a lot of heated vests out here, but I have heard of them. Seems like they are used quite frequently in 5C / 40F water though.

What gear are you using, and what is the range of temperatures?

 

[berndo]

We are both getting cold diving dry in cold water. We dive identical rigs. She believes we can help minimize the cold by simply adding more weight so we can, in turn, add more aire to our drysuits. I think this will cause a buoyancy control issue. My solution is to add thicker undergarments (which will likely drive us to add more weight). Which is the better solution? (If we add thicker undergarments, will the potential added weight cause similar buoyancy control issues?)

If you don't want to get thicker undergarment you can get a piece of fleece fabric (300gr or more), cut it into the shape of your torso (like the front part of a vest) and stick it under your undergarment. Makes a huge difference, cost next to nothing and you don't have to add a lot of weight. It's IMHO better than a vest or a thicker base layer, as it just adds more insulation where you want it.
Just adding weight doesn't help when the undergarment already has enough space to fully expand.

 

[Edward3c]

Building on earlier comments it’s not necessarily thicker undergarments, but the number of layers each trapping air.

As for winning, your wife will always be right (even if she’s wrong).

 

[Valeriy Vakshul]

Blow argon.
The thermal conductivity of argon at 0 degrees is 0.016 W/mK, and that of air is 0.024 W/mK.

 

[PR_SMITH]

We are both getting cold diving dry in cold water. We dive identical rigs. She believes we can help minimize the cold by simply adding more weight so we can, in turn, add more aire to our drysuits. I think this will cause a buoyancy control issue. My solution is to add thicker undergarments (which will likely drive us to add more weight). Which is the better solution? (If we add thicker undergarments, will the potential added weight cause similar buoyancy control issues?)

Adding more air won't give an even distribution of heat, and will will make ascents/buoyancy a little harder to manage if large amounts of air have to be vented. Using weight to try and solve an insulation issue is a poor idea.

Get better thermals, and drygloves(if not already using them). Also, consider a neoprene neck seal, they are much warmer, and last for years(mine's about 10)

 

[lexvil]

Adding air alone will make whatever part is lower in the water colder, managing the bubble is easy enough but that bubble will pull any looseness up toward the surface and squeeze the Insulation at the lower area and reduce its insulation properties.