Ice Diving Operations
By Ray Whitfield, ADCI-certified commercial dive supervisor. Reviewed by Amanda McCallister, editor.
Commercial Diving Contractors Alabama | Commercial Diving Contractors Alaska I remember a January job on the Penobscot River, air at -12°F, ice three feet thick, and a failed log gate at a mill intake. We cut a six-foot square hole with a chainsaw, and I went in wearing a Viking drysuit over two layers of fleece, a Kirby Morgan 17 helmet, and a stainless steel hat on top. The water was 34°F, black as pitch, and the current wanted to push me sideways. That's the reality of commercial ice diving. It's not a sport. It's a job that's got to get done. Intakes clog, valves freeze, and utilities don't shut down because the thermometer reads zero. So we drill through the ice, rig the tenders, and get on with it. I've been doing this for 28 years, ADCI-certified, all inland and industrial work. Ice diving is a niche within a niche, but it's a necessary one. This post is about how we do it — the gear, the procedures, and the mistakes you learn to avoid.
The Setup: Ice, Access, and Preparation
Before we cut a single block, we make sure the ice is solid. For a one-man operation we won't go under less than eight inches of black ice, but on a river with current, I want a foot or better. White ice is honeycombed; it might look thick but it punches through like bread. We use a spud bar to check every few feet, and we keep an eye on the weather — a thaw can change everything in a day. Access is a big deal. In remote spots we've used airboats, snowmobiles, and even a helicopter with a sling load. But the principle is the same: you need a safe platform to work from. We cut a hole at least 5x6 feet, sometimes bigger if the diver's going to be working on a large structure. We keep the ice blocks away from the hole, and we rope off the area so no one steps on the edge. And we always have a heated tent. It's not luxury — a diver can't warm up in a sub-zero wind after a 30-minute bottom time. The tent is set up over the hole, with hot drinks and a heater. That's where the diver gets dressed and undressed, and it's where the standby diver stays dressed and ready.
Gear and Diving Equipment for Ice Ops
The equipment is specialized. For the diver, it's a drysuit — typically Viking or DUI — with heavy undergarments. A drysuit alone isn't enough at those temps; you need the right undergarments, and you need to know how to manage argon or air in your drysuit for warmth. We also use dry gloves, and a hood that seals to the suit. For breathing, we don't use scuba on most commercial ice jobs. We use surface-supplied air from a compressor on the ice or on a truck. That gives us an infinite air supply and, more importantly, a voice communication line. We run a Kirby Morgan 17 or 21 communications wet pot, and the tender can hear every breath. Scuba is used only for limited inspections, but even then, we have a spare bottle and the diver is tethered. Another essential is a hot water system for the suit — some divers use hot water suits, which pump warm water from the surface. But those are heavy and need a lot of power. On jobs where we're working in near-freezing water for more than 20 minutes, a hot water suit is worth it. Otherwise, we limit bottom time and use a standard drysuit.
Safety, Tending, and Communications
Every ice dive has a tender — that's the person on the surface holding the diver's line. The tender's job is to keep the line clear, communicate with the diver, and be ready to pull. We use a strong braided line, and the diver has a harness and a weight belt that can be released. The tender also has a knife to cut the line if the diver gets snagged. Communications are crucial. We use a hard-wired system — Kirby Morgan's surface-air console with an intercom. The diver talks, the tender talks, and the supervisor listens. We also have a set of tugs: one for 'okay', two for 'take up slack', three for 'haul me out' — but we mostly rely on voice, because hand signals are useless in black water. And we never let a diver go under without a standby diver in the water or at least completely dressed and ready. I've had a diver's line freeze into the ice, and it took the tender and a second diver to chisel him out. Having that standby diver is the difference between a scary story and a recovery. Another thing: the diver wears a rescue knife on their belt and a cutting tool on the harness. But in ice ops, the real danger isn't entanglement — it's hypothermia and disorientation. So we set a time limit, usually 20 minutes, and we check the diver's condition constantly.
Operational Considerations and Seasonal Timing
Ice diving is strictly seasonal in the Northeast and Midwest. Usually we work December through March, but some years we get a late start. The window is short, so we plan jobs months ahead. We look for temps below 15°F for two weeks to get good ice, but on a river, the current can create pressure ridges and weak spots, so we always check on-site. One thing we've learned is that you never assume the hole stays open. Refreezing is a real nuisance. We keep the hole clear with a submersible pump or hot water circulation, but sometimes we have to chip ice every 20 minutes. And if the diver is working under a structure, we sometimes need to make two holes — one for entry, one for exit — if the structure blocks the route. Another seasonal consideration is the turnover in the industry. Many commercial divers come from coast guard or military backgrounds, and they're used to diving in different conditions. But ice diving is a skill you build by doing it with someone who's been at it for years. I still learn something new every winter.
Frequently Asked Questions
How thick does the ice need to be for safe commercial ice diving? For a one-man operation, we look for a minimum of eight inches of solid, black ice. On moving water or for heavy work, we prefer a foot or more. White ice or crumbling ice is a no-go — even if it's thick, it can be weak. Do you need a special certification to do ice diving commercially? You need an ADCI-certified commercial diving qualification, plus experience with drysuits and surface-supplied equipment. Some dive shops offer specialized ice diving courses, but the real training comes from working with an experienced crew. Why don't you use scuba tanks for ice diving? Scuba tanks limit your bottom time. For commercial work, we need longer bottom times and reliable communications, so we use surface-supplied air from a compressor. That way, the diver is fed air from the surface and can talk to the tender. What is the main danger in commercial ice diving? Hypothermia is a big one, but so is entanglement and disorientation in black water. The tender's line is the diver's lifeline. We also worry about the hole freezing over or the diver drifting under a shelf. That's why we have a standby diver, and why we set strict time limits.