Question for Cold Water Divers- Heated Vests?

We're diving in Alaska this summer and looking forward to everything but the water temp, about 42-45f. Has anyone used a Thermalution heated vest? They look pretty expensive for something that might just be an ineffective gadget. I would love to hear from someone that it really makes a difference, so I can justify throwing ever more money into this amazing hobby.

Thanks,

Fletcher

Heating vests are lovely, but they do add a layer of complication. I would make sure your undersuiting, gloves and hood are up to the task first before going there. Making sure you don't overheat and sweat before getting in the water is important too!

I found a heating vest very useful for cold water deco, where I would have it switched off for the working part of the dive, then switch it on for the cold and sitting still part at the end.

I'm ashamed to say I am a wuss when it comes to cold water. I dive in California, and when the temps are in the mid 50's, I think more about my discomfort than I do about the dive. I already wear dry gloves, good undergarments,... I may get a thicker hood, but I' m at 5 mm right now. That's why I started looking at manufactured heat!

In that case, go for it! They're like magic. Some thoughts:

- being too hot can be worse than being too cold. I think external control is a fantastic idea. You can get drysuit inflators that have a cable and switch incorporated into them which saves putting another hole in your suit.

- electronics and water inside your suit are a bad idea. Running a cable through the suit allows for an external battery pack, and a wet connector means you can swap to a new pack if the power runs out.

- if you're doing any loss of surface diving, heater failure contingency plans should be a consideration.

- if you're into DIY, the motorcycle community has some nice stuff.

Have you tried double hooding? I found wearing a polar fleece balaclava under my neoprene hood significantly reduced water flow around the ears. Not great for your hairstyle though.

I saw a very interesting presentation from a Dr (I cannot remember his name for the life of me...US chap...) who had spent a long time researching thermal stress and diving. If memory serves me well, thermal vests have some issues;

Turn on the vest just as you get in the water...during the dive your body is warm and on-gassing is aided by this warmth.

If its a long dive, how long will the heated vest keep you warm?

If your body is chilling at the end of the dive, off-gassing (decompressing) will not be helped.

I think the theory goes along the lines of "If you are warm at the beginning of the dive, loading your tissue up with gas is easy but at the end of the dive those chilled tissues may not be so willing to give up their gas"

But I can't remember the exact details - I just seem to remember that a heated vest may have some downsides that may not be apparent or obvious.

I saw a very interesting presentation from a Dr (I cannot remember his name for the life of me...US chap...) who had spent a long time researching thermal stress and diving. If memory serves me well, thermal vests have some issues;

 

Turn on the vest just as you get in the water...during the dive your body is warm and on-gassing is aided by this warmth.

 

If its a long dive, how long will the heated vest keep you warm?

 

If your body is chilling at the end of the dive, off-gassing (decompressing) will not be helped.

 

I think the theory goes along the lines of "If you are warm at the beginning of the dive, loading your tissue up with gas is easy but at the end of the dive those chilled tissues may not be so willing to give up their gas"

 

But I can't remember the exact details - I just seem to remember that a heated vest may have some downsides that may not be apparent or obvious.

You got it right! If you are warming (causes vasodilitation) at depth you will on gas more and if cool (causes vasoconstriction)at deco you offgas less. The other post when he switches it off at depth and on at deco will work, but there are no corrections built into deco algorithms for this in todays tables or computers.

I'm ashamed to say I am a wuss when it comes to cold water. I dive in California, and when the temps are in the mid 50's, I think more about my discomfort than I do about the dive. I already wear dry gloves, good undergarments,... I may get a thicker hood, but I' m at 5 mm right now. That's why I started looking at manufactured heat!

I recommend a 10mm hood by the swedish company Waterproof. http://www.waterproof.eu/

The extra thickness makes a big difference because you lose a lot of heat via your head. You might even consider adding the 2mm ice hood on top of the 10mm hood...

I dive with a very thin DUI TLS 350 Extreme and the Waterproof 10mm hood year around. I use Weezle Extreme Plus underwear plus 100% wool undergarments. http://www.weezle.co.uk Now during the winter the water has been 0...4 degrees Centrigrade "warm" and my dives have lasted between 60 and 90 minutes. On a 60 minute dive I hardly notice the water temp except the icy sting on my cheeks (when diving without the ice hood). On a 90 minute dive, it does get quite chilly though.

Eventually I might consider a heated vest. For safety reasons, a proper vest should be powered by the battery canister of your light and should be disconnectable.

btw Friends of mine (a mrs and a mr) made a six hour exploration dive in 5-6 degree water in Norway. Their opinion is that the dive would not have been possible without Weezle underwear http://vimeo.com/48209039

http://www.divernet.com/Diving_Gear/diver_tests/1323806/undersuit_thermalution_yellow_grade_advanced_heated_undervest.html

Fletcher, I have been using a Thermalution vest since last July. It can be used under a wetsuit or drysuit, so it is with me on all my local dives, as well as many of my warm-water trips. I do tend to add time to my safety stops for added safety. Worth noting: the wireless transmitter is best used topside - before entry - as the transmission doesn't work as well in water. I've done it, but you really have to get the transmitter close to the receiver, which will be on your back. Tricky, especially in a drysuit! Anyways, I love (LOVE) that vest, love it. It was worth every penny.

By the way, if you're going to the Scuba Show, the Thermalution people tend to discount about $100 if you buy it on-site. I about knocked the table over running to pass them them my credit card last year.

Allison

Thanks Allison, I didn't know they had a booth at the show. That would be a perfect time to try them on to get the right size... if I can wait till June.

Very good information about increasing safety stop times. I can count on one hand the number of > 1 hour dives I've made in cold water. Maybe with the vest, I'll be able to stay down longer. I think these vests maintain heat for well over an hour.

F

10mm hood... I'd really want to try that on. I expect it would make a huge difference in warmth.

I know it is off-topic but I'd like to put I another vote for the 10/5mm hood from Waterproof.

I've used one through two winters now and it and drygloves are the best innovations for cold water diving and cold water photography that I can think of.

Adam

Sorry to hijack the thread but it is not quite off topic anyway...

I've used one through two winters now and it and drygloves are the best innovations for cold water diving

Adam,

What dry gloves are you so happy with?

I've been using Si-Tech gloves QCB (http://www.sitech.se/pages/default_uk.asp?SectionID=3363) for the past 5 years or so.

Along the way, I've also used Bluepoint (no longer made), Northern Diver (too complex), DUI Zip seals (very good, but only for DUI drysuits) and Hydrotech cuffed gloves (awkward to use and only suitable shallow or for short dives)

Actually, only the cuff rings are Si-Tech, the gloves are just Showa 660 work gloves bought cheaply from eBay.

I use Fourth Element's excellent dry glove liners with them: http://www.fourthelement.com/images/gloves/glove-liners-tb.jpg

Adam

Thanks Adam,

This is what I needed to know.

Pete

I might just throw a spanner in to the works..

I see too often people using a heated vest to solve a problem that has not been addressed properly. To be warm in the water is a combination of many factors and more of them should be explored before resorting to a vest.

it may have been said before but it is worth re-iterating. Spend some money on a suit and make sure it fits properly. MTM always wins out and there are some really good small manufacturers that will give the big names a real run for their money. Get the right suit for the diving you are doing: the bouyancy characteristics of 9mm neoprene will knock your bouyancy for six on the bottom when deep for eg.

Oops.. thats the call for dinner.. back in a mo..

Bob -

I see your point...but I will say that many women I know tend to get colder than men on the same dives. I can't speak for Fletcher, though I can tell you I've been in the water with her, and she uses top-quality gear that fits her well. However - for myself - I have used lots of different suits and undergarments for lots of different types of dives, and I see the heated vest for my current diving not as a crutch, but as a tool that allows me to be far more comfortable without adding more bulk. I am already carrying around 75% of my body weight when I get in for an average dive, and more lead to sink thicker undies is not an appealing proposition. Just my 2 cents from a woman's perspective.

Fletcher, don't know if we'll see you before June, but if so, you're welcome to try my vest on. Love that thing. They say 4 hours on high - I was using it for 3 x 70 minute dives in South Komodo just fine (medium intensity), and I have used it on 2 x 90-95 minute CCR dive days in California (low and medium)on several occasions. I did have to replace the batteries recently, but I use the vest 2 days a week on average, and up to 7 when travelling.

Allison

PS - Adam, I remember you mentioned those gloves to me previously....I need to get a pair!!!

I have used lots of different suits and undergarments for lots of different types of dives, and I see the heated vest for my current diving not as a crutch, but as a tool that allows me to be far more comfortable without adding more bulk. I am already carrying around 75% of my body weight when I get in for an average dive, and more lead to sink thicker undies is not an appealing proposition. Just my 2 cents from a woman's perspective.

 

 

I hear you and am not knocking heated vests. I just think people see them as a panacea for not getting the rest of their kit in order. The SoM is 6degC at the mo and I will happily do 70mins in the water, mostly taking photos. I wear a 2.5mm neoprene suit, exerotherm arctic, weazel extreme, 7mm lobster mits, CCR (which helps enormously...umm warm air, nice!) and more socks than a centipede.

I have never tried a heated vest so take my comments in that vein too.

Dive safe

Cheers

Bob

 

I hear you and am not knocking heated vests. I just think people see them as a panacea for not getting the rest of their kit in order. The SoM is 6degC at the mo and I will happily do 70mins in the water, mostly taking photos. I wear a 2.5mm neoprene suit, exerotherm arctic, weazel extreme, 7mm lobster mits, CCR (which helps enormously...umm warm air, nice!) and more socks than a centipede.

 

I have never tried a heated vest so take my comments in that vein too.

 

Dive safe

 

Cheers

 

Bob

Well, if you are using a CCR you get warm air instead of cold. It makes a heck of a difference!

Those few degrees makes a lot of difference.

In the most Alpine lakes around here it is 4°C and certainly in Winter. I am pretty comfortable for 30 minutes. After 40 minutes the shivers are coming.

I have a custom made suit that fits well.

At 6-7°C the shivers arrives a lot later. If I am diving with a CCR they just do not show up!!!

I can clearly understand the reason and need for a Heated Vest!

/Erik

Get a suit that fits properly.

Wear appropriate undergarments.

Wear a suitable hood.

Wear suitable gloves.

Use a Thermolution heated vest.

Use a CCR.

Use proper nutrition.

(I think that covers it!)

Get a suit that fits properly.

Wear appropriate undergarments.

Wear a suitable hood.

Wear suitable gloves.

Use a Thermolution heated vest.

Use a CCR.

Use proper nutrition.

 

(I think that covers it!)

You forgot Bioprene ...