DIR and Ice Diving

[elan]

I'm just pointing out when under the ice in most cases is not like being in a tube or passageway. Most caves and wrecks give you very small cross sectional areas to search, where under the ice your in open water. Even our local DIR instructor teaches the diver/tender method.

That's a good point...

 

[elan]

Why do you assume a mile? With proper line awareness safety spool should be more than enough for lost line drill.

You time is more limited by cold water, the dexterity is much worse, the risks of free flows are elevated, unlike few directions you can have in the cave in a lake it's virtually unlimited. Those all things just multiply the risks and hinder your abilities to do the drills quickly.

 

[Jim Lapenta]

I had also wondered about this. One other question is if using a tether do you still dive in teams of three? I'm doing my second and third Ice classes in Jan and Feb. Actually assisting in the instruction to qualify to teach it myself. When we are under the ice the team(2 divers) is hooked to one rope via a Y arrangement that allows a max of 12-15 feet of separation. The instructor will go with the team for the first dive to do skills and will be on a separate tether or on one that can be moved along the main depending on their preference and level of experience. It would seem that a team of three would increase chances of things getting tangled up. When using a separate tether though there is usually ample surface support in training sessions. Last year we had two holes and two teams down at a time. There were 2 tenders at each hole, a back up, 2 safety divers in rotation for each, and at least 4 other instructors ready to go quickly. There were 15 divers in the class. Plus the wonderful ladies who had hot coco, sipping chili, warm cookies, etc for between dives.

As to hazards I also saw lines get caught under the ice plug when it was not kept taught enough or divers had buoyancy issues. When that happens a good tender is worth his/her weight in gold since at that point line communication is cut off. Picture 10 of 10 on my website under photos shows this. A line caught up against the ice can also be hard to see.

http://www.udmaquatics.com/photos/Ice Diving--under the ice.jpg.html

 

[elan]

There were 15 divers in the class. Plus the wonderful ladies who had hot coco, sipping chili, warm cookies, etc for between dives.

And doing cheer-leading ?


We dove in teams of 2: 2 down, 2 tethers 1 safety and the instructor

 

[DA Aquamaster]

In terms of cave diving, I don't want to do a lost line drill in some portions of Manatee either, so saying that large size is an issue wth a lost line drill in ice diving is a bit sort sighted.

The issue on an ice dive using cave techniques is to not to get too far off the line before you stop and do the drill. Worst case you screw up badly get 20-30 feet off the line and realize you are silted out. Tie off to and drop a back up light etc on the bottom and gently to a circular search pattern until you encounter the line. It's just not that hard to do, and no worse than a couple hundred zero viz searches I have done in commercial and PSD situations.

I have in the past done ice dives with a line similar to a cave dive (tie the shot line to an ice screw on the surface, do a primary tie off on the shot line, a secondary on the bottom if able, and then conduct the dive like you would any other cave dive using rocks, logs, etc for placements when available and PVC stakes when nothing is available.

Now, when doing this I will not take any diver with me who is not cave trained and who does not have superb buoyancy and fin techniques.

Freeze flows are a distinct possibility but the ability to shut down a freeflowing post and swap regs ensures a constant gas supply - and after a few mnutes you can turn the freeflowing post back on as the reg will have thawed and will no longer freeze flow.

One thing I would never consider doing however is an ice dive in current, unless the current is flowing toward open water with no possibility to switch directions.

 

[rjack321]

Yeah that particular quarry is very small and can be traversed within 10-15 mins range. That makes a lot of difference.

Ummm yeah the idea here is to pick sites that aren't way out there in terms of difficulty - because you <could> just come back with a boat to do the dive in a few months.

Ice diving is for fun and practice in the "off" season. Tethers limit the ability to practice some skills effectively (ummm like line running ) I don't think silt is a huge hazard to competent ice divers, just like it isn't in a cave. Current is the big no no regardless of tether. If its a particularly challenging site (like Lake Erie) then its probably better done in the summer.

 

[Gilldiver]

Here is some diving in Antarctica from the late 90’s but has some good stuff

Diving Under Antarctic Ice

Scroll down and see what a truly frozen regulator 1st stage can look like
Diving Under Antarctic Ice

There are some Sweds that wreck dive in the winter by driving out to a wreck site in the Baltic using GPS, cut a hole and ice dive the wreck. I don’t know many that crazy.

 

[captndale]

Most folks were consider the slack line dragging around a hazard unto itself. If the bottom is bereft of tie-offs people usually bring PVC stakes.

Yes, I believe I noted that a slack, negatively buoyant line is to be avoided. I don't know the conditions where you dive but here pounding a stake into the bottom would be guaranteed to blow a cloud of silt that would reduce visibility to inches for 10 yards around and take days to settle out.

The DIR solution to catastrophic gear failures is to bring doubles at a minimum. Doubles as backup and breathing a stage is also common. Good technique and breathing patterns minimize free flow failures - as well as using quality very low dewpoint gas.

Yes, I would not do an ice dive without doubles but a stage is not warranted. Triple redundancy is just overkill and a stage bottle increases the likelyhood of entanglement. The probability of freeflows can be minimized but not eliminated.

Getting hauled back to the surface is not really an appealing contingency plan for cave and technical divers - even when they are doing less committing recreational dives.

Getting hauled back is not something that happens without the diver asking for it. It can be fun. Make yourself buoyant, invert yourself and stand on the underside of the ice. Give your tender the emergency signal and "ski" upside down back to the hole.

 

[PfcAJ]

I don't ice dive, but wouldn't you just run a line since there are no installed permanent lines?

If thats the case, you're holding the line or your buddy is. So unless one of you loses a hand...

 

[DA Aquamaster]

Yes, I believe I noted that a slack, negatively buoyant line is to be avoided. I don't know the conditions where you dive but here pounding a stake into the bottom would be guaranteed to blow a cloud of silt that would reduce visibility to inches for 10 yards around and take days to settle out.

Where I have been, if you have to actually pound the stake into the bottom, silt is probably not going to be a problem. In contrast if the bottom is silted, it is usually deep enough that you can just push the stake in the bottom and no silt at all usually comes up.