Question Drysuit temperature and time limits in 13C and 24C water

[Underwater Tourist]

Posting it here instead of the exposure suit sub-forum

So I used to have a drysuit, but I sold it years ago because I just didn't dive in cold water often enough to justify owning it.
Now that I progressed to stage diving, it is only a matter of time when I will need it again, so I want to get a rough idea what temperature and time ranges it can sustain me for.

I know everybody has different cold tolerances, but we all know what works on average for an average person, so let's use that as a benchmark.
(For what its worth, my longest dive was 3h in Mx cenote at 24-25C wearing 5mm wet suit +3mm vest and I came out warm and cozy. It was only 3rd day of diving tho.)

As for the drysuit, I don't want to use it for super cold ice diving. The goal is to stay toasty during longer stage dives in ~13C water (basically EU caves) or during warmer, but longer, Mx cave dives that might involve a dpv (I am not trained to use it yet, but just looking ahead).

My understanding is that with a regularly cut drysuit you can wear 250g max undergarments, if you want to wear anything thicker and warmer, then you have to make the suit more baggy. Ideally I would like to avoid that.

So my questions are:
-For how long would a drysuit with 250g undergarments sustain an average diver in ~13C and in ~24C water? Let's assume a dpv as well.
-And will a regularly cut drysuit have enough room to accommodate 250g undergarments + heated vest, or will it have to be something like 150g + heated vest? How long would you expect an average diver to last in ~13C and ~24C water with that combination?

___________
* 13C = 55F
* 25C = 77F

 

[Aura]

but we all know what works on average for an average person

I think if that was the case, then this thread wouldn't exist
It really does vary incredibly much from person to person. One of my regular buddies uses thicker undergarments than me, but he'll be approaching hypothermia before I begin to feel even slightly chilly.

It'll vary between brands how much space there is for undergarments, so I'd suggest that you try a potential suit on with the thickest undergarments you plan to wear if possible.
Are you sure you'll want/need a heated vest? It doesn't really sound like you'll be diving in water so cold it can't be fine with appropriate, non-heated undergarments. Personally I'd want to rely on a battery as little as possible on dives that can't be easily terminated.

 

[Imla]

In Mexico I did 4hrs with two thin layers of wool baselayers. No gloves. No Hood.

In France, I did a couple hours with a Kwark Navy and a baselayer. (Didn't exit because of cold)

In Norway (4c) longest was a 3,5hr dive with a Kwark Navy extreme, 2 layers thin merino wool, 1 layer terry wool, and a heated west.

I would never use a heated vest in Mx.
I have different suits for use in warm/cold water. (Mostly because I won a drysuit and already had one... so I could indulge in a winter and a summer suit (read: backup suit))

 

[Underwater Tourist]

@Aura yes I know there is a lot of variance, but there is also an average

And as for the vest, the only reason I mentioned it is in case 250g won’t been enough. So I was looking for the next warmest option without increasing the size of the suit

 

[berndo]

-And will a regularly cut drysuit have enough room to accommodate 250g undergarments + heated vest, or will it have to be something like 150g + heated vest? How long would you expect an average diver to last in ~13C and ~24C water with that combination?

A regular cut drysuit is not really a thing. You need to try the suit on with the thickest undergarment you're going to use it with. For 13C I wouldn't use anything thinner than a bz400 or equivalent. You don't need a heated vest.

 

[Wibble]

13C. Depends on a lot of things; how active you are, etc.

BZ400's nice, but layers are just as good and cheaper. Keep the torso warm, but do be aware of loosing your dexterity if you're a backmount valve twiddler.

Don't forget decent gloves for the fingers; decent socks for the feet (I use Warmbac caving socks which work very well).

A heated vest is good too. Expensive though: vest + E/O drysuit inflator connector + battery are easily over €$1k, much more with a big battery.


24C. Drysuit with thinner garments. Still use a decent insulated vest though. And socks.

 

[Underwater Tourist]

@berndo yeah i was going off seaskins “regular” cut that is the default for them vs “extra space” cut that accommodates 450g undergarments. I should have been more specific in my OP

So bz400 is a 420g undergarment, which would require more room in the suit. Can I achieve the same warmth by doing a thinner undergarment and using a heated vest? Or it goes against some best practices?

@Wibble assuming a dpv dive without much movement, what would be a ballpark estimate?

 

[berndo]

Thin undergarment and a heated vest is a sh_t plan for deco diving, IMHO. You don't want to be warm on the dive and cold on deco if the heater craps out. Some people are OK in 250gr or FE artic at around 10c for a couple of hours. I'd be freezing.
As Auro said, people's cold tolerance varies a lot.

 

[Wibble]

Thin undergarment and a heated vest is a sh_t plan for deco diving, IMHO. You don't want to be warm on the dive and cold on deco if the heater craps out. Some people are OK in 250gr or FE artic at around 10c for a couple of hours. I'd be freezing.
As Auro said, people's cold tolerance varies a lot.

Nonsense.

Being warmer on deco is supposed to aid decompression.

Typical dive profile is do the bottom phase with the heating off -- you're working down there. Then turn the heating on when you're cold.

Of course if the heating failed, you'll be colder, so you must have sufficient undergarments to complete the decompression sans heater.

BTW heating isn't "hot", it's more like "not cold". If you used heated garments you'd understand that.

 

[Underwater Tourist]

That’s what berndo is saying, to avoid the situation when you are cold on deco because your heater breaks. I know you guys don’t like each other, but let’s reserve it for other threads