Cold Comfort: Dry Suit Undergarments | Scuba Diving

Cold Comfort: Dry Suit Undergarments

April 2002
By John Francis

Dry Suit Undergarments Reviewed in This Article

USIA Exotherm II USIA Thermolux I Oceanic Thermo Wear O.S. Systems DU-NJ Nylon Jumpsuit Diving Concepts Stretch TPS Thinsulate Extreme Viking Comfort Plus Whites Glacier System

Of course you don't have to use the undergarments marketed specifically to divers. Some of them are virtually identical to thermalwear sold to skiers, and the chain sporting goods stores offer many choices that will work fine. Look for hydrophobic fabrics like polypro and polyolefin, which will stay warm and dry-feeling even if there's a little seal leakage or sweat.

Some companies, however, have designed undies with features specifically aimed at divers.

Among them are:

  • An outer shell that's wind- and waterproof (or at least water-resistant). Even if seals don't leak, some water tends to splash inside when you unzip and take the collar off. With a shell, the splash doesn't soak in.

  • Stretch panels. More stretch in the back and waist improves your range of movement.

  • Wrist and ankle restraints. Either elastic cuffs or thumb loops and stirrups keep arms and legs from pushing up when you slip into the dry suit.

  • Thumb loops. These are actually misnamed because you need to pinch the thumb loop, not stick your thumb in it. Otherwise, it's a bear to retract your thumb and stuff the loop inside the seal. Elastic wrist cuffs usually work as well and are better at keeping warm air inside your sleeve.

  • Styles. There are two basic styles of undergarments: jumpsuit and jacket/pants. Jumpsuits don't leave a gap at your equator, but can inhibit mobility unless stretch panels are included. And the top half may not fit you as well as the bottom half, a problem you avoid when you can buy the pieces separately. Finally, the inevitable surface-interval urination can be more difficult in a jumpsuit--though men will be glad to know that all of the jumpsuits tested had double-ended zippers that were long enough for easy access.


Be careful. All of these are billed as machine-washable unless noted otherwise. But beware of a hot dryer, because heat murders miracle fibers like Thinsulate. Either tumble on a cool setting or hang to dry.

Use very little soap with Thinsulate, too. We're told that soap residue makes the stuff absorb water instead of repelling it, which would pretty seriously degrade its famous powers of insulation.

Product Reviews

Excellent: *****
Very Good: ****
Good: ***
Fair: **
Poor: *

USIA Exotherm II

| | USIA Exotherm II| Rating: ****

The Exotherm II's insulation is not only thick, it feels soft and cozy. It would be enough for pretty cold water, but those wanting more insulation can choose the Exotherm III. It's the same jumpsuit with a 4-ounce layer of Thermolite inside for another $59. (Thermolite is a DuPont polyester fiber sandwiched with its own windproof shell.) The elastic waist keeps the jumpsuit from sagging, and elastic across the shoulder blades gives stretch there. Thumb loops are also elastic so they're easy to stretch far enough to pinch easily.

Style: Jumpsuit.
Sizes: 5 unisex.
Lining: 16-ounce fleece.
Shell: Nylon.
Strengths: Lined hand-warming pockets, inside breast pocket, elastic waist, shoulder.
Weaknesses: No elastic wrist cuffs.
Price: $190.
Contact: USIA, (800) 247-8070.

USIA Thermolux I

| | USIA Thermolux I| Rating: *****

Still not warm enough? The Thermolux is really a farmer john, giving you a double layer over most of the torso. The bib completely covers the chest and has adjustable, elastic suspenders. The lining is the same cozy 16-ounce fleece as the Exotherm II. With an additional layer of 4-ounce Thermolite inside, it becomes the Thermolux II and costs $64 more. The john has the same well-designed, double-ended zipper as the jumpsuit. The jacket has elastic cuffs, which seem to work as well as thumb loops with less hassle.

Style: Two-piece.
Sizes: 5 unisex.
Lining: 16-ounce fleece.
Shell: Nylon.
Strengths: Lined hand-warming pockets, inside breast pocket, elastic wrist cuffs, elastic waist and shoulder.
Weaknesses: None.
Price: $265.
Contact: USIA, (800) 247-8070.

Oceanic Thermo Wear

| | Oceanic Thermo Wear| Rating: ****

This is very similar to USIA's Exotherm jumpsuit, and in fact seems cut from the same patterns except for the contrasting of color on the torso. The Thermo Wear I has a lining of 16-ounce fleece; the Thermo Wear II adds 4 ounces of Thermolite, a DuPont brand name for polyester sandwiched between windproof layers. Both versions have a water-resistant nylon shell, two outer pockets, one inner pocket, thumb loops and stirrups. A stretch panel across the shoulders of both suits adds flexibility.

Style: Jumpsuit.
Sizes: 6.
Lining: 16-ounce fleece, 4-ounce Thermolite.
Shell: Nylon.
Strengths: Lined hand-warming pockets.
Weaknesses: No elastic wrist cuffs.
Price: Thermo Wear I, $125; Thermo Wear II, $168.
Contact: Oceanic, (510) 562-0500.

O.S. Systems DU-NJ Nylon Jumpsuit

| | O.S. Systems DU-NJ Nylon Jumpsuit| Rating: ****

Ankle cuffs are hard to force your feet through, so you may have to ease them over with your hands. Stirrups seem redundant, but you've got 'em. Wrists have beefy elastic cuffs which make thumb loops unnecessary and also close your sleeves. Despite some stretch in the fleece lining, in the legs it tends to lie in folds and wrinkles which you might feel come suit-squeeze time. The DU-NJX jumpsuit has an additional layer of 13-ounce fleece and costs $299. And, in a laudable gesture toward gender equality, a DU-SJ stretch fleece jumpsuit with a drop seat is available for $138.

Style: Jumpsuit.
Sizes: 6 unisex.
Lining: 16-ounce polyester fleece.
Shell: Nylon.
Strengths: Stretch panels under arms, in crotch. Elastic waist. Elastic wrist cuffs.
Weaknesses: Ankle cuffs make donning difficult. Hand- warmer pockets poorly cut, not lined.
Price: $208.
Contact: O.S. Systems, (503) 543-3126.

Diving Concepts Stretch TPS Thinsulate Extreme

| | Diving Concepts Stretch TPS Thinsulate Extreme| Rating: *****

The lining and the shell of this suit are quilted, "sewn together," so both move together and the lining is less likely to make uncomfortable folds. Shoulder pads cushion your BC straps, a nice touch. The material also stretches, so it hugs your body yet allows easy movement. The shell is a water-repellent, slippery nylon that slides into your dry suit easily. The lining is a thick layer of fleece backed up with a layer of Thinsulate, 3M's famous high-performance, low-weight insulation, which should make this unusually warm for its weight and bulk. The regular suit gets a 100-gram layer; the Extreme version gets a 200-gram version. There's a price to pay for Thinsulate, however: soap residue makes it attract water, not repel it, so the makers recommend hand-washing with minimum soap. And keep it out of the dryer.

Then there's the other price, the $500 tag on the sleeve. Can an undersuit be worth almost as much as the dry suit itself? Maybe. At any rate, this one has more exotic material and more finicky workmanship than many a dry suit. With thumb loops and stirrups.

Style: Jumpsuit.
Sizes: 8 men's, 6 women's.
Lining: 10.75 ounces polyester fleece plus 200-gram Thinsulate.
Shell: Nylon.
Strengths: Quilting. Slippery shell makes donning dry suit easier. Long, double-ended zipper. Shoulders padded for BC straps.
Weaknesses: Should be hand-washed. No elastic wrist cuffs.
Price: $500.
Contact: Diving Concepts, Inc., (805) 692-2001.

Viking Comfort Plus

| | Viking Comfort Plus| Rating: ****

This already thick suit is meant to be worn over a woolen terry-cloth undersuit: Evidently, it really is cold in Sweden. The Comfort Plus is actually the middle of three weights; the Oden has fleece only and the Arctic Plus has the fleece plus 400 grams of Thinsulate. The Comfort Plus has an elastic waistband in back but otherwise doesn't stretch, so your freedom of movement is somewhat limited. The nylon shell has a sort of rough finish, which doesn't slide into the arms and legs of the dry suit as well as some others. A nice touch: Thick, elastic wrist cuffs eliminate the need for those silly thumb loops while keeping warm air inside your sleeves.

Style: Jumpsuit.
Sizes: 6.
Lining: Trevira fleece plus 200-gram Thinsulate.
Shell: Nylon.
Strengths: Heavy insulation. Wrist cuffs.
Weaknesses: Feels stiff, restrictive.
Price: $295.
Contact: Trelleborg Viking, (603) 436-1236.

Whites Glacier System

| | Whites Glacier System| Rating: *****

Let's talk layering. Let's talk versatility. There are the many obvious combinations of john and inner jacket (a soft fleece) and outer pant and jacket (fleece plus Thinsulate plus nylon shell). Then there's the interesting fact that the sleeves unzip from the jackets and can zip onto the john. So the inner and outer jackets can become vests, and the john can become a jumpsuit. From fleece john or jumpsuit to, well, everything at once, you should be able to handle any temperature range. A bit pricey if parts are purchased separately, but look for a package deal. Pants have stirrups; jackets have thumb loops. Machine washable on the outer pant and jacket only, but beware of killing the Thinsulate. Dry cleaning is recommended by the manufacturer.

Style: You name it.
Sizes: 9 unisex.
Lining: 12-ounce fleece in base jacket/john. 12-ounce fleece plus 100-gram Thinsulate in outer pant and jacket.
Shell: Nylon.
Strengths: Versatility.
Weaknesses: No elastic wrist cuffs.
Price: Base jacket, $138; base john, $138; outer jacket, $218; outer pant, $158.
Contact: Whites, (250) 652-8554.