This was probably because we were influenced by an attractive young lady called Caroline Munro, who was employed to advertise Lamb’s Navy Rum and was seen on street posters throughout the UK.
Without her diving knife, Caroline would have been wearing virtually nothing at all. A big knife strapped to a thigh made one look extremely competent, and she looked competent!
Of course, there are many diving locations in the world where the use of a knife by a diver is banned, but if you dive in conditions of low visibility where fishing activities might take place, having a knife could save your life.
Many wrecks around the UK are draped with nets that have been caught and lost by trawlers, and many popular wrecks are also liked by anglers, who entangle their monofilament lines in the wreckage and lose it so that it can entangle unwary divers later.
So young Caroline from Lamb’s Navy was probably armed to ward off unwelcome attention on the beach rather than under water.
She would have got into trouble had she been diving and got caught up in netting, because having her knife lashed to her leg might have made it difficult to reach. She’d have done better to strap it to her upper body.
A knife is not used to fight off marauding sharks. That would only annoy them.
A knife has to be good at cutting through netting and fishing line, and it has to stay good until the day you need it.
I have a fantastically sharp knife that I use to carve the Sunday joint, but should I ever take it diving, it would disappear before my very eyes.
The sort of steel that will take a fine edge does not take kindly to exposure to sea water, and soon rusts away. So a diver’s knife needs to be made from a metal that is impervious to these conditions.
Many knives are made from 316 stainless steel, but this cannot be honed to a sharp edge.
A close examination of any diver’s knife will reveal either an example that is lovingly cared for with grease between dives, a shiny one that wouldn’t slice butter, or one that is very rusty and heading for uselessness – unless it’s made of titanium.

The Knife
Titanium is lightweight, strong, hones to a sharp edge and doesn’t corrode easily. It is also expensive. I don’t know how PDE does it, but its Triton Tek knife comes at an attainable price. It has a 12cm blade with a slicing edge and a gently serrated edge, as well as a hook for cutting monofilament line.
The Triton Tek is available with either a pointed or a chisel end. I recommend the latter. There are laws now about the carrying of knives like this, and you don’t want to spend Sunday night in a cell awaiting the magistrate’s court in the morning, just because you got involved in some fracas in a chip-shop on the way back from a dive.
The grippy handle is anatomically shaped, with a soft rubber insert and a hammer end that could be used for breaking a window of your car, should you return from diving to find that you’ve lost your keys!

The Sheath
I used to have an enormous collection of diving knives, but never bought one. I would find them lying on the seabed, and I found another only the other day.
It was new, and stood out loud and proud on the reef. It was another casualty of a poor method of stowage, which is why the sheath is almost as important as the knife.
The Triton Tek knife has a positive method of fitting in its sheath that includes a handle that interlocks, and it clicks into place in a manner that imparts confidence that you won’t lose it.
The plastic sheath can be worn with rubber straps in the conventional way, but it also comes with a neoprene holster that can be strapped almost anywhere, including an upper arm, or even to your tank. I don’t recommend strapping it to a thigh unless you are a fair maiden and getting paid to pose for pictures, because thigh muscles flex while finning, and it will soon be dangling round your shin.
Like any item of emergency equipment, it needs to remain forgotten about until the day you need it. You should wear it where you can reach it, should you suddenly find yourself in the deadly embrace of netting or fishing-line.
Either way, even at the PDE price, you’d be heartbroken to lose this knife – just as I would be overjoyed to find it.

Atomic, £88
TUSA Xpert, £86

BLADE Blunt or pointed
DRY WEIGHT 307g with neoprene holster
DIVER GUIDE width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100% width=100%