Knot for ice diving rig

[Gary D.]

The strength of a BC, BP&W or what ever you are using to secure your tank does not matter in this case. You need to use a separate harness designed to hold at least your body weight under your gear.

The reason for this is that should you have to remove your gear to clear an entanglement or whatever you are still attached to the surface line.

If you pulled your gear off and for some reason lost it, due to poor vis or poor buoyancy for you or the gear and your safety line was attached to it simply put Your Screwed.

All those fancy rings on your gear, other than a separate harness, are attachment points for more gear not a life support line.

Now an exception is a search line. Open water doing search patterns go ahead and use the rings on your gear. In situations where you are just using it to hold a pattern line and not using it for life support go ahead.

Even if you could repel with your gear do not use it, get a harness and clip in with a locking beaner.

DRI is teaching the use of a Quick Release on the line to the beaner on your harness. But only for open water search applications. Not under the ice.

All that is secured with locked figure eights.

Gary D.

 

[AndyNZ]

Having experience with ropes in the mountaineering field I would personally go with the figure eight. It is the only knot we trust to tie in with.

What? The only...? I must have been doing something wrong for the last twenty odd years!

The Figure of 8 has it's advantages but also it's disadvantages. It's 10% weaker than a bowline and virtually impossible to undo once it's been heavily loaded. It's advantages is that it's difficult to tie wrong (if you get it wrong, you get an overhand knot) and as such is "mandated" to new climbers.

The bowline is perfectly fine, as long as you have a locking half hitch. The double bowline (very similar to the water bowline) doesn't have the same tendandcy to come undone and doesn't need a half hitch to lock.

And what about if you tie in at the middle of the rope? A Figure of 8 becomes dangerous because if both ends are pulled you are pulling across the major axis of the knot, weakening it further. Tying in the middle of the rope (e.g. group of three, glacier crossing) is much safer using an Alpine butterfly which transmits load along the rope, not through the knot itself.

There's no such thing as "the only" knot - there are always choices and with experience you choose different knots for the same application depending on circumstance.

I would guess that ice diving is much the same - all the knots would work, with various advantages and disadvantages.

 

[grazie42]

I wouldn´t tie the line to my BC. The whole point is that you should be able to remove the bc and still be tied to the surface.

Whatever knot you use, be sure that you know how to tie it and that you trust it, because you ARE trusting it with your life...

This weekend we sawed thru 40cm of ice to get into a lake...for me there is no question that the risk/benefit analasys of ice-diving tilts heavily towards the "benefit"-side...Go for it!