Why should I use an undersuit?

[tonytheteal]

After a bit of info here please

I have a roomy neoprene drysuit and currently I dive in a fleece and jeans (or tracksuit bottoms), and if it's cold I add a more few layers. Looking round at Stoney the other day I seemed to be in a minority, most I saw had undersuits.

If I'm comfortable and warm (and don't get cold after a dive) should I change to an undersuit? If so why and what would you recommend? I guess my uk diving calender would be may to sept max.

I'd be keen on hearing everyone's views but if there's any DIRers I'd esp like to know your thoughts.

Cheers

J

[Mark Powell]

If you are warm enough in your neoprene drysuit then you don't need an undersuit. Many of the divers I know who use a neoprene suit don't wear an undersuit and just wear thermals or a Fourth Element during the winter.

A membrane suit is a different case as it doesn't provide any thermal protection, unlike a neoprene suit.

I'm not DIR but my understanding is that DIR divers don't use neoprene suits and so the question doesn't arise for them.

[Devon Diver]

If you're comfy and warm, stick with what you currently wear.
Unless you want to shell out more money for no real gain.

Roy

[Ainsleyberryman]

A proper undersuit not only keeps you warm, it also keeps moisture away from the skin. Its wicks away moisture - when you get kitted up in the warm you will sweat a lot and you dont want this next to the skin. Also some moisture may enter the suit, again this should be wicked away.

A proper undersuit will also not foul dump valves - some have had problems with this and you may see tape on some arms/cuffs as a result.

While not essential, it will make a difference on cold dives - I use a Posiden neoprean suit and have tried it without an undersuit, with tee shirt and now with two undersits so I never get cold or wet.

[Richie]

For summer use I tend to agree with you. A T shirt and shorts can be OK for shallow/short dives but in cooler water and deeper when the neoprene is compressed a good undersuit makes life much easier. Under Neoprene a 100g thinsulate is enough I find even for 60 mins in 5 degrees 30+m.
An undersuit is also less likely to obstruct dump valves.

Anyway a nice soft babygrow is much more comforting and cooler than a bit of blanket

[divingniknaks]

Tony , hope this helps , from GUE's site, doesn't mention too much about under garments but gives a few pointers.

Mark,
DUI one of the most "recommended" DIR suits is neoprene btw, hope that helps.

From GUE.com

Divers entering cold water or engaging in more extreme exposures will often choose to utilize a drysuit for increased warmth. Drysuits are typically of two primary types: shell-type or neoprene. Neoprene drysuits may come in different thicknesses, adding to their insulation. However, a thicker neoprene suit adds buoyancy, increasing a diver's need for extra weight. One of the disadvantages to neoprene suits is that they will become thinner at depth, decreasing their thermal advantage and requiring additional insulation. This insulation, coupled with the positive nature of the neoprene, can further add to the buoyant nature of the suit. At shallower depths, the crushable tendency of neoprene is less significant, giving the suit more natural insulation.

One of the greatest advantages to the neoprene suit is its limited drag. Neoprene suits are generally very similar in drag to wetsuits, especially when fitted properly with limited excess material. However, neoprene wrist and neck seals are not typically as effective as the latex seals found on many shell-type suits and generally allow some water migration. Individuals may chose to use latex seals on a neoprene suit or utilize a double wrist seal system: a latex seal that is covered by a protective neoprene seal. Shell suits are constructed from a variety of materials and rely on undergarments to provide insulation. These suits typically depend on latex wrist seals which are generally more effective at preventing water from passing into the suit. Thinner latex seals are more effective barriers to water yet are more easily damaged, while thicker seals resist damage but are less effective at preventing water migration.

The drag associated with a shell-style suit depends on the material and the fit. For example, Viking drysuits are constructed from a thick material yet tend to be prone to a high degree of drag. The DUI TLS-350 suit has a telescoping torso design that allows for a tighter fit while maintaining ease of entry. The suit is also made from a trilaminate design that allows for a durable and flexible material allowing divers a greater range of motion. Generally speaking, shell-type suits are more flexible and less prone to water leakage than neoprene suits, yet can develop punctures or failures that allow significant water leakage. Drysuit manufacturers are always experimenting with new, stronger materials. In 2000, DUI introduced its CLX-450 suit with a shell of laminated Cordura. The CLX appears to have durability qualities more in line with compressed neoprene but with the flexibility, rapid drying time, and lighter weight of the TLS. Some undergarments incorporate insulation materials such as 3M Thinsilate that maintain most of their insulation properties even when flooded. Some suit manufacturers try to combine the durable advantages of neoprene drysuits with the consistent buoyancy of shell suits.

Crushed and compressed neoprene suits can limit the buoyancy changes of conventional neoprene by pre-crushing the material. The pre-crushed material provides more insulation than a fabric suit, yet is less buoyant than a conventional neoprene style suit. The DUI CF-200 suit is one of the most popular of these crushed neoprene styles and is widely known as one of the toughest suit materials currently used. However, a crushed neoprene suit is very heavy and takes significant time to dry. Furthermore, even crushed neoprene suits are less flexible than shell suits.

[andy_chesney]

Undersuits will keep you warmer than a t-shirt and jeans and will also wick away the moisture from your skin preventing you from getting cold.

If you are ok with just a t-shirt and tracksuit bottoms etc then an alternative would be some thin bottoms like the forth element or sub-zero stuff which have high wicking properties like an undersuit. They shouldf also be more comfortable.

[Simon Lamb]

'Proper' undersuits will offer you some thermal protection when they're wet aswell. Which your jeans and jumper wont. If you did have a leaky valve or seal, think about being wet and cold for your deco.... brrr... :>


HTH

[jim oldham]

Originally Posted by tonytheteal

After a bit of info here please

I have a roomy neoprene drysuit and currently I dive in a fleece and jeans (or tracksuit bottoms),

J

"cotton kills" is a survival mantra, because jeans will offer zero protection if you have a leak. (No, not that type). Cotton holds water therefore has no/little thermal protection.
However, if you are warm enough with just a layer of thermals good for you.
I have a membrane, so I need the extra layers, and I'm a big softey.
Jim

[turbanator]

Originally Posted by divingniknaks

Tony , hope this helps , from GUE's site, doesn't mention too much about under garments but gives a few pointers.

Mark,
DUI one of the most "recommended" DIR suits is neoprene btw, hope that helps.

From GUE.com

The DIR suit of choice is a cave-cut mtm TLS 350, which is the thin membrane suit.

The CF which is mentioned is compressed after the suit is made rather than making a suit of pre-compressed material.

I've had a Polar Bears membrane, a CF and a TLS.
A lot of the guys in our club wear 'normal neprene suits (Solent Divers) and just wear a base layer or thos blue runing trousers with the red piping whose name escapes me.

r
P