Cutting Tools: The Backup Every Diver Should Carry

Ask a room of divers how many have ever cut themselves free of something underwater, and a few hands go up every time — a snagged fishing line, a drifting net, a tangle of kelp or a stray piece of rope. Ask how many carry a cutting tool, and it’s often fewer than you’d hope. That gap is worth closing, because entanglement doesn’t care how experienced you are.

A cutting tool is one of the cheapest pieces of safety kit you can own, and one of the few that can get you out of a genuinely dangerous situation. Here’s why every diver should carry one, the different types, and how to choose.

Why you need one, even in clear warm water

It’s tempting to think entanglement is a cold-water, low-visibility problem — something that happens to other divers, somewhere else. It isn’t. Discarded and active fishing line is almost invisible underwater and turns up on reefs and wrecks everywhere. Lost nets drift. Ropes, lines and kelp are part of plenty of dive sites. Get a fin, a valve or a hose caught in any of it, and calm turns to a problem quickly — and the more you struggle, the worse a tangle usually gets.

A cutting tool within reach turns that scenario from an emergency into a brief inconvenience: reach, cut, free, carry on. Without one, you’re relying on working the tangle loose by feel, possibly in poor visibility, possibly running down your gas while you do it.

The main types

The traditional dive knife

The classic. A dive knife does more than cut — it’s a pry tool, a tank-banger for signalling, a general-purpose tool. Modern ones are often compact and mount on a BCD or forearm. A blunt (chisel) tip is usually the sensible choice over a sharp point — you’re cutting line and prying, not stabbing, and a blunt tip won’t puncture a hose, a suit or you.

Line cutters

A line cutter houses a small, very sharp blade in a protected slot, so you hook the line into it and pull. It’s superb at its one job — slicing through monofilament and rope fast — with almost no risk of cutting yourself or your gear, because the blade is recessed. Many divers consider one of these essential specifically for fishing line.

EMT and trauma shears

Blunt-nosed rescue shears cut through a surprising amount — line, webbing, even light cable — safely and cheaply. They’re a favourite of technical divers precisely because they’re so safe to use in a hurry and handle materials a small blade struggles with.

The Z-knife

A tiny, hook-shaped cutter with a protected blade, often clipped somewhere immediately accessible as a backup. Minimal, safe, and purpose-built for slicing line — a popular second cutter.

How to choose — and where to mount it

Two questions matter more than the exact model. First: can you reach it? A cutting tool buried in a pocket you can’t get to, or strapped to a lower leg you can’t comfortably reach, isn’t much use in a tangle. Mount it somewhere you can get to with either hand, ideally without looking. Second: is it safe to use? Blunt tips and recessed blades mean you can cut confidently near hoses, suits and your own hands.

On material: titanium resists corrosion beautifully and needs little maintenance, which many divers love; quality stainless steel takes and holds a keener edge but wants rinsing and a little care to keep rust away. Many experienced divers carry two cutting tools of different types — a line cutter or shears plus a small backup like a Z-knife — on the reasonable logic that the one tool you have is the one that might drop, jam or be just out of reach.

Look after it

Like anything that goes in salt water, a cutting tool lasts longer with a rinse and a dry after diving, and a blade kept free of corrosion. Check periodically that it’s still secure in its mount and hasn’t worked loose — a cutter that silently fell off two dives ago isn’t protecting anyone.

Carry one every dive

It’s a small, inexpensive, easily-carried piece of kit that sits unused on almost every dive and earns its place completely on the one where it doesn’t. Browse our cutting tools and the other essentials worth keeping on your rig, and if you’re not sure what type or how to mount it, ask us — we’ll help you set up something accessible and safe.