Drysuit VS Semi Dry

[CAPTAIN SINBAD]

How does the performance of a semi drysuit compare to a drysuit in extremely cold waters?

I was having a discussion with another fellow diver with whom I intend to take an ice diving course. He was saying that if you have a custom made semidry with good seals then there is no need for a drysuit because it will feel like a neoprene drysuit that is super streamlined. But in order for it to be semi-dry it must be tailored to your body and unless you are built exactly like a stock size, you will be diving with a wetsuit. I have never been inside a semi-dry, nor could I understand the concept behind the term itself because you are either dry or you are not. There is no such thing as "semi-dry" just like there is no such thing as partially pregnant! Its either you are or you are not!

Can anyone who has used a semi-dry please tell me how you would compare the experience of a semi-dry with a drysuit?

Thanks -

Sinbad

 

[fisheater]

Colder in a "semi-dry" wetsuit.

My semidry is custom and fits well. Still, I'm definitely warmer in a drysuit.


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[CAPTAIN SINBAD]

Colder in a "semi-dry" wetsuit.

My semidry is custom and fits well. Still, I'm definitely warmer in a drysuit.


Sent from my iPhone using Tapatalk

Thanks! How thick is the semi-dry and what is the lowest temperature in which you would use it?

 

[BoltSnap]

Captain,

I have tried several Semi-dry suits, They are all BS. Waste of money and time. If you need to use a semi-dry or even a 7 mm suit, go to a real drysuit.

---------- Post added November 23rd, 2012 at 08:20 PM ----------

BTW, with semi-dry suit, any fluctuation in weight, they are either too tight and uncomfortable or loose and water gets in and it isn't semi dry or anything.

 

[Aqua-Andy]

I started out with a 7mm semi-dry and thought I was warm in 50f water, now after diving in a drysuit for four years I would not want to dive in water that temp wet again. My last dive wet was in 60f water and I was freezing after 45 minutes. I don't know if diving dry makes you a wuss or you just don't know what cold is until you are really warm.

 

[lowviz]

There is a situational aspect, too. Put me under the ice and I'm happy, an uneventful dive in 40-50 F water and I'll be ending early and cold.

 

[fisheater]

Thanks! How thick is the semi-dry and what is the lowest temperature in which you would use it?

It's a 7mm FJ and I dove with it down to 45F. It worked fine, but I was feeling cold after 30-40 minutes, way less if deep. No way to compensate for compression at depth, unlike a wetsuit.

The HUGE difference is during SI and afterwards. Being dry at the surface goes a long way to being warm. No way I'd div wet when the surface temps supported ice.


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[fdog]

My freediving wetsuit, which is made from expensive rubber and fits like spray paint, is the warmest wetsuit I own.

...My semi-dry was colder than my freediving wetsuit.

Neither are even in the same league as a real dry suit. IMHO, when you feel the need for a warmer wetsuit, just bite the bullet and step up to a dry suit.


All the best, James

 

[GrumpyOldGuy]

The old saying is semi-dry is the same as semi-wet. There is a reason people shell out 1500 for a D/S vs 500 for a custom semi-dry.

Basic physics, no matter how well the suit fits, there will be small areas of air entrapment. Between you giblets, under your arms, in the small of your back. These area will compress and some amount of water will get past the seals to equalize the pressure. If the seals were perfect you would be painfully squeezed. So now best bet your damp neoprene in direct contact with your skin. If you pee, then the urine is more concentrated and you can really reek. I have seen some semi-dry divers with the their arms and legs damp after a single shallow diver, but with multiple dives they are pretty much soaked.

 

[spectrum]

You need to be careful with the semi-dry term. Some are just really nice wetsuits. The mention of a Farmer John in post #7 is an example of how fast and loose the term is used.

A true semi-dry will be a close fitting sealed neoprene suit with no real intended air spaces. As such your insulation is solely from the neoprene and any way you slice it that degrades with depth and usage and is what it is. (Has anyone tried something like a garment Lavacore under one?) In the end you have a wetsuit with virtually zero water exchange. Most are designed for zero water exchange but given the product name seepage is acceptable. Users commonly claim to exit with a dry chest.

A drysuit has the advantage of being totally dry (when things go right) and allowing you to select thermal garments that are worn within.

Pete