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Wetsuits: How they work and how to choose

The mercury is on the rise again but sea temperatures are still playing catch-up. So before you venture out onto the water, do you have a wetsuit up to the job? We tell you what you need to know ...

Wetsuits: How they work and how to choose

Photo: RNLI/Nathan Williams

Homo sapiens has been having fun on the water since time immemorial.

But it’s only in the last 60 years we’ve been able to play in relative comfort – thanks to humankind’s insatiable demand for rubber and the good folk at DuPont.

The recreational wetsuit, made from neoprene – a revolutionary synthetic rubber invented by DuPont in the 1930s – has opened up a whole new world of watersports possibilities, enabling people to enjoy their sport in comfort and safety.

Wetsuit saves the day

When things do go wrong it’s reassuring to know that the right wetsuit can also be a lifesaver.

When waves swamped an angler half a mile offshore – capsizing his kayak and throwing him into the sea – he was lucky to survive. After being in the water for nearly 20 minutes he was rescued by Porthcawl lifeboat volunteers, and was able to walk away unharmed. Lifeboat Operations Manager Phil Missen reflects: ‘Fortunately the casualty was wearing a wetsuit and a lifejacket.’

How wetsuits work

Unless you’re luxuriating in a tropical ocean next to a palm-fringed beach (where the water approaches your own body temperature), your body will lose heat many times faster in seawater than in air. This is exacerbated by movement.

A wetsuit helps to retain body heat, as well as protect against scrapes and bumps and the harmful rays of the sun.

It also provides a degree of buoyancy.

Advances in wetsuit design and innovative ways of combining different materials together have resulted in today’s high-performance wetsuits that are warmer and more flexible than anything that’s gone before. But the basic idea behind them remains the same.

Wetsuits leak water – through the zips and seams, and the neck, arm and leg openings – to a greater or lesser extent.

The initial rush can be uncomfortably cold but once water has got in, a wetsuit helps to keep it there while the heat from our bodies warms it up to create what is, in effect, another thermal layer.

Some wetsuits – so-called semi-drysuits – let very little water in, but none are completely dry.

Choosing the right wetsuit

A rack of wetsuits

Photo: Shutterstock

With so much choice out there, where do you start? Wetsuit technology is continually evolving, so it’s worth doing your research. This quick guide will help you grasp the basics. And there is plenty of help at hand in specialist shops and online.

Warmth v flexibility

Choosing the right wetsuit is a trade-off between staying warm and being mobile – ask any windsurfer, diver or competitive open-water swimmer.

The biggest factor is fit, but there are other considerations too – design, thickness, method of construction and the quality of neoprene all play a part.

Getting the right size is crucial if your wetsuit is to keep you warm and comfortable. You want a snug fit – neither so loose that water continually flushes through, nor so tight that it constricts your breathing or makes it difficult to move. Wetsuits are supposed to be a bit of a struggle to put on. If you can’t find a wetsuit that fits, a number of manufacturers now offer made to measure.

Wetsuit thickness is measured in millimetres of neoprene: the thicker the suit, the more insulation. So a full wetsuit suitable for windsurfing in Summer in Wales might be labelled 3/2 (3mm neoprene core, 2mm limbs) and one for Winter might be 5/3.

Thickness labels don’t always give a true picture. For example, a suit might have thicker panels on the legs (to keep your legs warm) and thinner panels on the arms and shoulders (for greater freedom of movement).

Higher-end suits have glued, stitched and taped seams, and more panels for a better fit, comfort and better all-round performance. You can accessorise for warmth without compromising flexibility, for example by adding wetsuit shoes, gloves, hoods and hooded thermal vests.

If you need a wetsuit for your growing children, the chances are you’ll need to replace it before it wears out. But get advice before opting for a bigger size, or consider ex-rental. There are lots of cheap wetsuits in supermarkets these days, but if your children are getting into their watersports, you may want to dig a little deeper. In all cases, try before you buy.

Looking after your wetsuit

Like their wearers, wetsuits wear with age. Constant use slowly crushes the gas pockets in the neoprene, reducing its effectiveness. Saltwater, chlorine and, yes, urine, destroy neoprene, so it’s important to hose your wetsuit down and/or give it a good soaking after use. Drying and storing it folded (no sharp edges), or hanging it in the dark (UV will degrade the suit) will help preserve it.

You will inevitably get the odd nick or tear, but fortunately these are easy to repair with neoprene glue. You’ll find plenty of videos online showing you how.

Looking after yourself

An RNLI lifeguard zips up her wetsuit

Photo: RNLI/Nigel Millard

An RNLI lifeguard zips up her wetsuit

‘Advances in wetsuit technology have encouraged more of us to get out on the water, and for longer, but at a cost,’ says RNLI Lifeguard Manager and surfer Phil Hill. ‘The chance of something going wrong also increases. So the RNLI has extended the length of the lifeguard season at many of our beaches.’

Wetsuits are part of our lifesaving kit, helping lifeguards to save 94 lives on 225 beaches across the UK in 2015.

Despite being well maintained, RNLI wetsuits take a pasting and every year we have to replace hundreds of suits. It’s your support that keeps our lifesavers kitted out in all weathers.

By choosing the right wetsuit and looking after it, you can get out there and enjoy the water for longer. And you’ll be helping to keep yourself safe.

Top tips

Harrison Bates with surfboard

Photo: RNLI/Nathan Williams

Harrison Bates

Here are some top tips for all wetsuit wearers from scuba diver and RNLI videographer Harrison Bates.

  • Check out the discounts on last season’s wetsuits before you buy. There’s no point in buying a wetsuit with an extra green line down the side and paying twice the price.
  • To get your suit on easily, put plastic bags over your hands before plunging them into your sleeves. You can do the same with your feet.
  • Keep your zip running freely using beeswax, and ask a friend to zip your suit up to avoid damaging it.

This story first appeared in the Spring 2016 issue of Offshore magazine. Learn more about RNLI Offshore membership, for those who use the sea for fun.