Rope Style for Ice?

[MSDT Mark]

What is the preferred type of rope for ice diving? I know there are a couple styles of polypropylene rope, twisted and braided. Also, any tips on rigging carabiners for dive teams of two per line?

Twisted rope is formed by coiling three strands together in the same direction. Twisted rope must be fused and taped on each end to prevent unraveling.

Three general categories of braided construction exist: diamond braid with a core, diamond braid without a core (called hollow braid) and solid braid. If there is a core around which the rope is braided it cannot be spliced. If no core exists, the rope is called "hollow braid". The feature of hollow braided rope is the ability to splice it. Lehigh encloses a splicing fid with instructions in every bag of hollow braid poly. Solid braid is very firm, round and tightly woven with a special lock-stitch construction which prevents unraveling when cut or torn. Solid braided rope stands up especially well to chafing. However, this construction cannot be spliced.

What is the best way to go?

 

[Gary D.]

Lane B is our rope guy. He should be working tonight so maybe he can jump in.

I think twisted or hollow braid ropes are fine for a lot of applications but they don't belong on or under the ice. I'd look at higher quality ropes more related to climbing.

Gary D.

 

[bridgediver]

hey Mark

You seem to have a good grasp of rope capabilities already

twisted - I'd avoid as this stuff gets tangled and knots itself up pretty good

solid core (or climbing style) has alot of stuff going against it. As you stated already its very stiff and hard to work with - also it's heavy and almost all variations will sink (which creates a multitude of problems). This stuff also may cost up to 5X as much.
Climbing rope isn't really needed unless you're dealing with loads of a couple of thousand pounds -- We never are in a diving application although if you're working a current of say something like the Niagra river maybe something heavier is warranted

I'd advise 3/8" hollow braided polypropylene. Biggest advantages is that it floats, doesn't freeze (water/ice can be flicked out) and very pliable and doesn't tangle easy. This stuff is also fairly cheap so if you need to splice just throw it out and get a new peice(?).


We don't put 2 guys on one line so I can't help you there

 

[DA Aquamaster]

My preference for a tether would be something that is both strong (solid core) and abrasion resistant (an outer cover), as well as easy to handle (which eliminates many twisted ropes).

A 3/8" or 7/16" kernmantle rope is ideal in my opinion and a poly rope in that type of construction is easy to find and is fairly low cost (maybe $20.00 for 100') at the local walmart or boat store as they are commonly used for anchor lines or utility ropes. Stiffness is not a liability in a tether. In the water freezing is not an issue and in the water you absolutely do not want a rope that will loop or twist on itself if it goes slack as it has the potential to loop around a diver or his equipment increasing the potential for entanglement. That issue eliminates twisted ropes completely and braided ropes are not much better. There is a trade off in terms of the rope being stiffer out of the water as it will tend to freeze in the braided cover, but I prefer the in water advantages of a kernmantle rope to the out of water advantages of a braided rope.

Climbing ropes are usually nylon and never polypropolene - and you get what you pay for so a good climbing rope is very expensive and considered to be very life limited.

When securing the rope to a carabiner I prefer a figure 8 or a figure 8 on a bight. I have seen bowlines used but they can come loose when not under a load. I prefer not to use one even if it is backed up with a half hitch, etc as the rope is not heavily loaded during an ice dive.

A figure 8 can also be tied in the middle of a line if you want to have two divers on a single line. Personally, I prefer one diver per line with a single diver in the water with a tender and a stand by diver on the edge of the hole on a separate and 50' longer line with a separate tender.

This link shows both ways to tie a figure 8 knot (end of the line and in-line). Goes without saying but use a locking carabiner and use an appropriate harness.

knots

 

[bridgediver]

Hi DA

The solid core ropes and points you make are probably well advised for recreational ice diving but I'm thinking that the question is posed for a PSD application(?). If so, the utilization is different.

For PSD ice ops
- we need ropes that work well in and out of the water; wet(on the surface and u/w) or dry. In a real scenario we aren't going to hike the whole team out to the ice hole and "set up shop" like a rec ice diving class. We often have to send our divers down a different hole and maybe have to put the tenders in the water too.
So getting from the surface (or hole(s)) to the shore is a consideration that may be overlooked in the rec ice dive - we can't just walk back to shore in PSD
- a well trained team doesn't create any slack in the line whereas rec ice divers usually dive with slack lines most of the time. So stiff lines are an unecessary pain for PSD as it can limit movement and versatility of the line - to me this is a liability but others may disagree.


For the others:
A final word about rope strength because this is a common misconception - (and I will say that there is ONE type of solid core rope that you should consider and that is comrope).
The wire in a comrope is only rated to 450lbs breaking strength and the industry uses this rope for tether lines in many applications for PSD and commercial work and we don't see the wire breaking (otherwise they would have to build something better right?). This should say something to those that insist on rope rated for thousands of pounds. We aren't dealing with fall factors and rope dynamics in or on the water.
Bottom line is if you're pulling more than a few dozen pounds of force on the tether you're pulling too hard. True, the rope won't break but the diver will and so you should have another way of getting him out so you don't hurt him

So why do I say comrope? It is stiffer and not very pliable after all. The added safety of voice comms while under the ice is simply to good of a trade off. Our team SOG will not do a real ice op (or overhead) without voice comms.
But if comms are out of reach for you and you're just looking for rope you aren't getting any benefit from a stiff kernmantel or cored rope. Get something that is easy to work with and lower your task loading

hope this helps

mark

 

[bridgediver]

Regarding the walmart type rope. Its like what you said, you get what you pay for. I'd be very suspicious of 100ft of "kernmantel" rope for $20. If you look at this stuff allot of the time the core is made of paper or some other sort of natural fibre which is of course no good for the water unless you do a ton of maintenance.
If the core is a true synthetic its going to cost

 

[Gary D.]

The ropes we use year around are yellow and red. I don't know what they are but they work very well in or out of the water in summer or under the ice and last for years. They are very flexible, dry quickly and are easy to tie off.

It will be quite a while before I get back to work so I hope one of the other guys chimes in.

Gary D.

 

[DA Aquamaster]

Regarding the walmart type rope. Its like what you said, you get what you pay for. I'd be very suspicious of 100ft of "kernmantel" rope for $20. If you look at this stuff allot of the time the core is made of paper or some other sort of natural fibre which is of course no good for the water unless you do a ton of maintenance.
If the core is a true synthetic its going to cost

You can always look at the end and see what it has for a core.

I know we used to use this same rope in 3/8" diamter to secure submerged mooring buoys and would end up replacing it every few years just because we figured it was time. So...a constant load of maybe 25-30 lbs plus peak loads with a boat moored in a wind of maybe 300 pounds over the course of 2-3 years? I am not real worried about using it on an ice dive.

One note on ploy rope - it stands up well to moisture but will degrade pretty quickly when exposed to UV/sunlight, so store it accordingly.