Technology is allowing us to dive longer and deeper. In the early 1990s, the idea that technical divers could regularly dive beyond 100 meters / 330 feet was the stuff of dreams. Today it’s well within the norm.
We’re fortunate that thermal technology continues to advance, too, so we have garments made from lighter, warmer fabrics. However, we can still get cold on long exposures or dives conducted in temperate waters.
What’s the solution? In recent years a number of heated devices — vests, gloves and other garments — have emerged. These can make for a more comfortable dive, and can be safe when used in a thoughtful manner.
So how should active thermal systems be dived?
“If active warming is required, there should be enough delivered during the descent and bottom phase to preserve clear thinking and physical function, but no more,” according to research physiologist and thermal stress expert Dr. Neal Pollock. “This reduces any unnecessary increase in inert gas uptake. The amount of warming can then be gradually increased during ascent to enhance elimination. This, again, requires some consideration. The ability to hold gas in solution (solubility) decreases with increasing temperature. Heating a tissue laden with inert gas too quickly can promote bubble formation — definitely undesirable from a decompression safety perspective.”
The ability to control the output of your heated device is important. But what do you do if your heated device does not have an adjustable controller?
Dive Rite has just launched the Thermal Vest Regulator, or TVR, that can help solve this physiological problem.
“At Dive Rite we understand how important it is to have multiple power settings – this feature was a given from the get go,” stated Jared Hires, Dive Rite‘s marketing director. “We also thought it valuable to get input from the community before we designed this system. The overwhelming answer we received was that divers want to be able to mount a controller anywhere on their suit, with the preferred location being a bulkhead connection near or in the thigh pocket. The thinking behind this is that it will protect the controller. Plus it also allow the cable (the pig tail) to be tucked into the pocket when the heated device is not being dived.”
Since the bulkhead is in a pocket, the diver does not need blinking lights or other visual aids to confirm the status of the controller, according to Hires. Instead, the TVR has a positive vibrating alarm. When you switch it on, it vibrates once and the controller is set on high. Push the controller again and you get two vibrations, and the medium setting (75% power) now works. Push again, and the controller will vibrate three times, and work on the low setting (50% power).
The company has been asked how heated devices operate.
“Basically they have wires that run through the garment,” Hires says, adding: “When you push current through the wire it will heat up. The more current you run through it, the hotter it becomes, and there is potential for the wire to either burn out or run too hot. Our micro-controller regulates the voltage, that then determines the heat output, and only takes the energy it needs, rather than all the energy it can.”
Dive Rite has made their product very user-friendly, with built-in battery flexibility.
“We recognize that divers will want to have the option of using their current battery pack,” according to Hires. “Hence we have made our TVR capable of being powered by a variety of battery packs — from 10 volts to 18 volts. Moreover, divers will be pleased to hear that our TVR controller is intelligent, in that our TVR benefits from reverse polarity protection. What does this mean in the field? In the event that you use another person’s power pack then it won’t damage the controller.”
One important company ethos is that its products last for years, Hires told DeeperBlue.com.
“We have made our Thermal Vest Regulator future-proof,” he said, adding: “There will be that occasion when you don’t want to dive a heated device on a dive, or even for a season. The solution is to fit a blanking plate to the bulkhead.”