What Is A Dive Knife?

A dive knife is a tool that divers may need to use to cut fish lines that have become entangled around marine life – or to knock on tanks to get a buddy’s attention. They’re essential for wreck diving as tangled ropes and underwater plants are often encountered and need to be released. They’re never used as a weapon or to harm the underwater environment.

What is a dive knife? Do you need to have one? Find out more here…

Dive Knife Facts and Features

Modern dive knives are made from different blade materials – either titanium or stainless steel. Titanium knives are lightweight and very strong. They’re also corrosion resistant making them more expensive to buy.

Stainless steel knives are easy to sharpen but do need more maintenance to keep them from rusting. They can weigh twice as much as titanium knives.
Knives range in size from compact to large. On larger types, a metal handle butt can also act as a hammer. Smaller designs may be foldable.

A sheath with retainer enables you to attach it to your equipment – on the back of your console or your BCD. Or you can strap it inside your wrist or leg.

Choosing Your Dive Knife

Your dive knife will reflect the type of diving you do. Here’s a brief guide of the options available:

Blades – can be fixed or folding – a fixed blade can be easily removed from the protective sheath and used with one hand. A folded blade can be harder to open with one hand but is more convenient and safer to carry.

Blade Edges – straight or serrated – a straight blade will slice and cut nylon and plastics. A serrated edge will saw through kelp and natural fibres. Choose a knife that has both edges – and look for a blade notch that specifically cuts fishing line.

Blade tips – can be blunt, sharp, or tanto. Blunt tips are safer and prevent puncturing. Sharp tips are suitable for spiking fish when spearfishing. And tanto tips are a mix of the other two with a high point and a flat grind making them extremely strong.

Size – a more compact knife is often the preferred option. And a 7-10 cm blade will be enough to cut through netting. Bigger knives are suitable for spearfishing and kelp diving.

Comfort – make sure your hand rests comfortably in the grip. And allow for a good grip even when wearing gloves. Practice sheathing and unsheathing the knife so it becomes second nature.

FAQ’s Answered

Is a dive knife necessary?

A good dive knife is essential. You can free yourself or your buddy should you get entangled in fishing line or sea kelp. You can use it to anchor yourself to the sea bed during a heavy current to prevent drifting. Helping trapped marine life is another bonus. And your knife can also be used as a tank-knocker to get attention.

Why are dive knives blunt?

Sharp tips can cause punctures in your wetsuit, regulator, or your skin. Pointed knives are more often used for spearfishing. The edges of the knives are smooth, saw-sharp, or serrated – so the tips can be blunt to make the knife safer – and can be used for chiselling, hacking, and digging.

Do I need a dive knife for snorkelling?

If you’re snorkelling in areas where old fishing nets or sea kelp can cause a problem then a dive knife can be a good idea. Chose a compact type that can simply be attached to your lower leg.

Buy from the Experts

The Koox Dive Shop in Playa del Carmen, Mexico has all the dive equipment you need. And you’ll get help and advice to ensure you get the dive knife to suit you. Why not consider scuba diving or snorkelling with dive masters? You’ll be able to add your dive knife to the rest of your diving equipment. Knowing you’ll be able to free yourself in any emergency.