DIR and cold water dives with long decompression

[vioch]

How do DIR divers take into account drysuit failure while planning cold water (38F and below) dives with long (30-60 mins) decompression?

Some divers from Russia use drysuits with thick wetsuits as underwear to minimize undercooling on long deco if drysuit fails.


So want to know DIR options for such dives.

 

[coldsmoke]

I'll take a stab.

Don't do the dive. I am not sure what the official stance is from HQ, but even short deco dives in really cold water are a concern.

Hunter

 

[nadwidny]

Good underwear, short exposures.

Generally folks use DUI's Thinsulate 400 underwear or something similar that will keep most of its' insulating value even when wet. And in water colder than 40F we plan on a total runtime of around 60 minutes.

 

[MonkSeal]

Heated west. Although I don't use one I've seen few people with it during cold dives, switching it on ocasionaly during deco. I guess it works with flooded suit as well.

 

[lamont]

from what i've been hearing, heated vests are iffy and bad designs can burn you.

the bts vests seem to be the best out there that isn't DIY, but i've heard criticisms of them, particularly that they don't have a thermistor cutout.

the big problem, though, appears to be the wires in vests (and even the carbon fiber vests have wires to carry current to the carbon fiber) when they fray with age and form high resistance hot spots.

 

[nadwidny]

Heated west. Although I don't use one I've seen few people with it during cold dives, switching it on ocasionaly during deco. I guess it works with flooded suit as well.

We've experimented with vests. The best results so far have been the Patco pads although I don't think anyone has had the opportunity yet to try one in a flooded suit. A buddy of mine had a vest made for the motorcycle crowd that seemed to work great until he had a suit flood. The wires started shorting out giving him shocks.

 

[rjack321]

Thick ~12mm hoods or 2 thinner hoods
NEW 400gm thinsulate is nice, the weezles are "not DIR" but don't pack out to thin uselessness nearly as fast as thinsulate
short exposures
heaters are to supplement sufficient undergarments, if you require the heater you are beyond a safe exposure.

There comes a point when the risks of a suit flood are such that you just can't do the dive.

 

[vioch]

Why are weezles not DIR?

 

[nadwidny]

Because George said so.

 

[JeffG]

We've experimented with vests. The best results so far have been the Patco pads although I don't think anyone has had the opportunity yet to try one in a flooded suit. A buddy of mine had a vest made for the motorcycle crowd that seemed to work great until he had a suit flood. The wires started shorting out giving him shocks.

My suit had a leak in Halifax and probably the Patco heater made the dive bearable. No shocks, but I wasn't soaked either.

Also...the motorcycle vest after the flood was basically ruined. The wires were too corroded.

A note on using electrical heat. You don't do the dive requiring the electrical heat to get you through the dive...its just a bonus if it works.

Also, only use it on deco on not on your bottom time.