YOU YOUNG PEOPLE DON’T KNOW you’re born! When I was a lad, we had coal fires that were dead in the morning, and bathrooms that had ice on the windows – on the inside.
Discomfort was something we were expected to put up with.
My dad would never have a heater in his car. He said he’d only get used to it, and then what would he do if it stopped working
Divers went to 30m deep off Britain’s coasts wearing nothing more than their swimmers and a woolly jumper. But diving was not for me in those days. I don’t enjoy being cold.
The latest item of kit to cross my path goes into the “whatever next” category. It’s an electrically heated vest that is waterproof, and can be used under a wetsuit to a depth of 70m.
Well, motorcyclists were tough when I was a lad, too, yet now they often wear heated vests under that butch leather.
So why not divers with electrically heated vests under their wetsuits?
I had visions of sparks and frizzled hair, but there was no Wiley Coyote to test this product for me. So, in the tradition of Haldane and other scientists who try out test their own theories on themselves, I did the same with the Taiwanese-made Thermalution Heated Wetsuit Vest.

The Vest
The packaging claims that this is a powered inner layer that turns any wetsuit into a heated wetsuit. It comes as a sleeveless vest or T-shirt, and in three sizes. I tried the large size, but a snug fit is recommended. I’m sure it will fit you more manly guys, too.
It employs a non-metallic heating wire set in a stretchy Nylon/Lycra material. Two pockets retain the slim battery-packs, and a controller is set at the end of a curly cord.
The controller has sequential switching for three heat settings identified by red, orange and green LEDs.
Disconnect the battery-packs and screw the captive protective caps onto the connection leads, and the vest is washable.
Endurance is claimed to be an hour at full power. Naturally, reducing the power setting increases the endurance time.
The charger has coloured LEDs to indicate that the vest is charging, and that a full state of charge has been reached. It can be plugged into almost any mains supply or the 12V connection (once known as a cigarette lighter) in car. It is designed to charge both battery-packs at once.

In Use
If I was initially concerned about being electrocuted should anything go wrong, I soon realised that the voltages used are so minimal that this would never be the case.
To avoid hotspots, I would wear the vest over a thin cotton T-shirt. I fed the control cable up through the neck of the wetsuit, with the zip at the back left slightly open to let it pass through.
The Thermalution Heated Wetsuit Vest uses “Far Infrared” technology. This wavelength of light is invisible, but can penetrate deep into the human body, where it creates resonance and gently elevates the body temperature. Besides providing warmth, it can accelerate metabolism and improve blood circulation. Well, that’s what the folks at NASA say, anyway.
I also wore the vest with nothing more than trunks while photographing my daughter on her Junior Open Water Diver course in a pool.
This proved a pointless exercise. Without a barrier of Neoprene to keep the warmed water in, the small amount of heat produced was simply conducted away by the water, whichever of the three heat settings I chose. A normal rash-vest would have provided similar warmth.
I’m told that the company intends to bring out a version suitable for use with a drysuit.
It will have a wirelessly linked control, to avoid breaching the watertight integrity of the drysuit.

PRICE £359
ENDURANCE 60min at full power
BATTERIES Rechargeable lithium polymer
DIVER GUIDE width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100%