1. not always, several factors contribute to the contour of ice. Clarity of ice is another issue. Sometimes ice is so clear underneath that the bubbles spreading across the surface are the best indicator of where it is. Always look up when ascending and look for your bubbles or raise your arm above your head in bad vis so you don’t smack your head on the ice.
2. generally yes, again dependent on how the entrance is constructed, angle of diver to tender, and any types of obstructions that may be encountered under the ice between the tender and diver.
3. depends on the thickness, clarity, and conditions of the ice.
The majority of my ice dives have been working dives and not recreational so we set them up a bit differently depending upon what we are trying to recover. Most of the time, we shovel off the snow to create lanes that branch out from the entrance in a star pattern to help guide the diver back if needed. Sunlight on the clear lane is contrasted by the snow so they are rather easy to see. If the ice is “dirty”, we drill down every 10 feet in the same pattern and attach a chem light. We used green, yellow, and red (green closest to the entrance) to help divers find their way if needed. If you came up and see a yellow chem, you follow the line. If it turns to a red chem, turn around and follow it the other way. Whatever you decide on safety measures, don’t out-dive the system. In other words, don’t set up a safety system that only extends 100’ if you plan on letting the diver line run out to 175’.
Granted, many may find these things unnecessary and simply tie off a line and jump in. Everyone has their own way or policies/procedures that will dictate how this type of dive is set up. While the above setup worked for us, it may not apply to others depending upon location and reason for dive. Also a big difference between running a dive such as this with a large dive unit versus two or three divers going out for an ice dive.
The lines we use are rather large and I have never witnessed a line coming off a diver or being cut. Tie a good knot and it should not be a major issue. As with any diving like this, plan the dive and dive the plan.
