Drysuit course - Warm vs Cold waters

[Subcooled]

If you keep the air bubble as small as advised on p.48 of the DUI Drysuit manual, you won't even notice it..

Good manual!
Yes, the free air volume can become a problem (or a fun challenge... it depends on how you look at life).
Air does provide good insulation, but if it is all in one place and nowhere else, then it does not help.
I just hate shrink wrapping myself. Just a preference. Choose yours, and live with it.
Btw, this is why I prefer thick undergarments the year around.
The fact that bottom temps are always the same does help, however...

 

[Gandalf-the-Diver]

As a tech diver, I will be taking a drysuit course in backmount doubles, and I can't decide if I should do the course in Tulum/PDC (I'm cavern certified) or a far and expensive drive away from me in a cold lake.

I plan to dive dry in US NorthEast and NorthWest (~45-55 degree temps) cold water, therefore it would make sense to learn the drysuit in cold water with my 150g thinsulate undergarment, however I would really prefer to just do my drysuit course in Mexico (with only a base layer) so I don't have to deal with that trip. My concern is that if I learn in Mexico, then when I incorporate my thicker undergarments it will be a problem for me.

Does the amount or type of undergarment have that big of an effect when learning to dive dry, or is it small enough where after learning how to use a drysuit I will be able to use those skills across all garment types?

Taking the drysuit course, in warm water, will still teach you how to use a drysuit. Once you move to cold water, the different layers you wear under your suit, will directly affect your buoyancy, and weighting required. It does not take much to change weighting requirements either. I just did a dive the other weekend and forgot to take off a long sleeve shirt I had on, before I put on my fleece layer; I also had a base layer on. I am minimally weighted normally, and I found that the thin nylon shirt I left on, made it trickier for me to descend, and I was a little floaty at the end of my dive. I normally have about 31lbs of lead, and I use use a Faber HP100 for a tank. You will want to do a weight check when you 1st hit cold water.

 

[Subcooled]

Taking the drysuit course, in warm water, will still teach you how to use a drysuit.

True. You will become familiar with the basic principles.

Once you move to cold water, the different layers you wear under your suit, will directly affect your buoyancy, and weighting required.

It also drastically affects the buoyancy change per foot of water in the shallows. Maintaining neutral buoyancy at shallow depth with thick undergarments (or a lot of free air) becomes much more difficult.

And please remember that drygloves instantaneously take you down to 120 feet. The clumsiness is immeasurable before you learn to cope with it

and I found that the thin nylon shirt I left on, made it trickier for me to descend, and I was a little floaty at the end of my dive.

I share your pain. Been there, picking stones from the bottom

I normally have about 31lbs of lead, and I use use a Faber HP100 for a tank. You will want to do a weight check when you 1st hit cold water.

I do wear 12 to 18 lbs but I always dive with two steel cylinders, large or small. The joy of sidemount diving makes much weight unnecessary (yeah, I've also heard of people with two cylinders on the back).

 

[inquis]

Maintaining neutral buoyancy at shallow depth with thick undergarments (or a lot of free air) becomes much more difficult.

I rather view this as a good reason to take the class in thin layers if that's an option -- walk before you run, so to speak.

 

[Litefoot]

As a neophyte drysuit diver, I have appreciated having 60 F water that allows me to go gloveless. It helps to learn the tactile location of the added shoulder dump and suit inflator.

 

[inquis]

It helps to learn the tactile location of the added shoulder dump

I don't normally touch the shoulder dump. It stays fully open.

 

[happy-diver]

Stretching my shore dives to the last appreciable bar within regulations I keep mine closed