Help me understand wet suits for cold water

[Marie13]

I have buddies who dive semi dry in fairly cold water.

If you know that you’ll need to dive fairly cold waters and do not want a drysuit you should definitely consider it.

I wouldn’t do it myself because I find my drysuit much more comfortable and warmer.

Please not that a semi dry is actually wet inside: just that you the water does not migrate as much due to the seals. But this means that you might be actually really cold during the interval/break/between dives.

That’s why you drop the top of your semi dry and wear a good coat and maybe even a hat. Buddy who has a semi dry forgot his coat once on a Lake Michigan charter and froze his butt off - 130ft dive at 41F.

 

[Eric Sedletzky]

I’ve used every style of 7mm wetsuit imaginable for Norcal diving which is from the mid 40’s up to mid 50’s depending on time of year and upwellings.
I can say the best overall option I’ve used was a 7mm skin-in freediving suit, two piece beaver tail design with attached hood, no zippers. They a bit of a challenge to get in and out of because of no zippers but they are the warmest wetsuits currently on the market. The material generally tends to be softer so there are depth limitations because they crush out easier than denser material, but if you’re staying less that 60’ - 70’ they’re great!
There are many brands and some brands do offer suits made from denser material for the deep divers.
The trade off is they’re harder to move in.

 

[Frogkicker]

I am extremely temperature sensitive and have to dive a warmer suit than most others on the same dive.

If diving wet the fit is really important to me, the better fit the warmer you will be.

My favorite wetsuit so far is the oniell J type. It is a one piece with an attached hood and separate but attached vest built in. I can drop the top and keep the vest on under a jacket on SI.

 

[Midwesterndvr]

A semi dry is still a wetsuit.

 

[Midwesterndvr]

Buy a well fitting 7mil wetsuit, unless you can justify the expense for a “semi dry” which doesn’t offer a noticeable advantage for the cost. Also if your doing a lot of diving up there you may be looking at dry anyways in the near future.

 

[Vitesse2l]

What Marie says about a coat and hat.

Plus, for me, a hot drink.

 

[JackD342]

Marie, what makes a semi-dry suit different than a wet suit?

Also, semi-dry is usually a little thicker at 8mm versus 7mm, and usually has a different (more difficult to put on) entry method. Usually a zipper across the front/chest from shoulder to shoulder, so you need insert yourself into the top end of the sausage casing.

 

[lakehuronjoe]

Do you buy hoods and boots in the same mil thickness as the wet suit?

 

[Marie13]

Do you buy hoods and boots in the same mil thickness as the wet suit?

When I was diving wet, I’d use 5mm boots with neoprene socks under them. I always went with a 5mm hood.

Semi dry suits have an attached hood so you don’t need to get a separate one.

I always went with 3mm gloves even in low 40sF water as I prefer dexterity and can deal with chilly fingers as a trade off.

 

[BlueTrin]

Do you buy hoods and boots in the same mil thickness as the wet suit?

You don’t have to

When you try your hood, if you plan to go in cold water, I would make sure that you can fit the mask skirt under the hood so you don’t expose your forehead.

Maybe it’s just me but if I forget to put my hood correctly to cover my forehead I get colder quicker and it gives me sometimes slight headaches ...

For gloves, I would make sure you can manipulate things and that it is a snug fit.

I had a pair of 7mm gloves from 4th element, I couldn’t feel a thing and it made everything harder under water.

Since then I am using a 5mm glove which is nearly as warm (the fit is better so I have less water movement) and provides much more dexterity.