Roughly speaking, most oceans and seas change temperature by around 10° between seasonal lows and highs. For many divers, this means that local conditions will require a rethink of the kind of exposure suit they use as the water warms and cools.
Travelling UK divers might need a suit system that covers them from a near-freezing quarry in a UK winter to the high tropics in summer.
For wetsuit-divers in temperate and cold waters, those diving exclusively in warm water and the in-betweeners like me, who dive a range of locations across the temperature spectrum, the Mares 2nd Skin shorty could prove to be a good investment.
Shorties can be a versatile addition to your scuba and snorkelling wardrobe. I got to test the 2nd Skin as both a coldwater undersuit and a standalone warmwater suit.
If you normally dive in wetsuits and are feeling the chill, using additional layers such as shorties to increase the neoprene barrier between your warm body and the surrounding cold water will delay heat-loss. The benefit is staying warmer for longer.
Sometimes a shorty is worn over the main suit, other times underneath. I first tried the 2nd Skin in Gibraltar as part of number of wetsuit tests that took place in 14°C or so, with dives as deep as 40m, sometimes with some deco thrown in.
With some dives edging towards 90 minutes and at cruising depths that would significantly compress the suit and reduce insulation, getting cold was inevitable.
Indeed, the point of the dives was to test the limits of the suit subjectively by finding out how long it took me to start shivering.
I wore the 2nd Skin under my test coldwater wetsuits, as recommended by Mares. Another reason was that my test suits were a little large on me and, though they sealed well, reducing flushing, I still had more cold water in the suit than was ideal. The design of the 2nd Skin also lends itself to skin contact.
In wetsuits, the greatest heat-loss occurs from flushing, when a suit doesn’t fit properly and water is able to flow in and out.
Water entering absorbs body heat and takes it with it when it leaves. Your body can rarely generate enough warmth fast enough to replace lost body heat, so you chill.
Most wetsuits have a nylon inner lining. This helps protect the neoprene from tearing as you put it on, but the ease with which it slides over skin also means that water easily passes it by.
The 2nd Skin’s inner is rubber-faced rather than nylon-lined, so tends to stick to your skin, all but eliminating flushing.
Like other premium Mares wetsuits, the neoprene contains Metalite, which is claimed to reflect back some lost body heat.
Glideskin, also used on some Mares semi-drys, is used to seal the legs. There’s a wide backing flap to minimise water flushing through the zip, and an unusual bib that tucks into the suit to create a further seal around your throat.
Seams are not dry-stitched. For durability, the outer suit is nylon-lined. The main body of the suit is only 1.5mm, which makes it very supple, but I assume that such a thin suit needs the Metalite and nifty seals to stay effective.
Although it’s a shorty it has long sleeves, but just above the elbow the material changes from neoprene to Lycra.
When worn under a well-fitting wetsuit, full-length neoprene sleeves would be difficult to put on and make flexing your arms difficult.
Thumb-loops at the wrists help you keep the sleeves in place as you put your wetsuit on over the top. When using the 2nd Skin by itself, the sleeves provide a little protection from abrasions and stingers under water, and sunburn at the surface. The shorty certainly made my coldwater dives in Gib more comfortable.