Shark Shields and Powerheads – Risks and Uses
Both Shark Shields and Powerheads are means of deterring large predators. Each method has its limitations and both excel in their own ways.
The Ocean Guardian Freedom 7 is more commonly called the “Shark Shield”. It uses an electric pulse that sharks find extremely uncomfortable to deter sharks from approaching within a few yards (meters) of a diver. The Freedom 7 is a great deterrent specifically for sharks, because other large predatory fish don’t have the same electro-magnetic sense that sharks have. There are many divers and surfers that won’t get in sharks waters without one of these.
The Freedom 7 relies on a rechargeable battery. It trails behind the diver like a surf board leash and regularly emits an electric pulse through the water. They are a little expensive, but they are capable of reducing threats you may not even be aware of in the water.You do need to be cognizant of turning the Freedom 7 off before getting out of the water. Once the device is wet it can arc on a boat and shock anyone touching it. Ocean Guardian also makes a unit designed to be installed on a boat.
Powerheads are a more reactive solution to large predators in the water. There are a few kinds of options for different powerheads. With all powerheads you should waterproof the round you are using with colorful nail polish. We recommend colorful nail polish because you can see if the paint is falling off. Once the powder is wet in the round it is useless. Paint around the head (where the primer is) as well as neck of the round (where the projectile is).
One of the big risks of powerheads is hitting a solid object accidentally. The force of the explosion from the powerhead hitting a solid object (shipwreck, rock, etc) can launch your spear shaft back at you as if you just pulled the trigger at yourself. Be aware of where you are sending the spear shaft ad the possible repercussions.
Powerheads do not go onto slip-tips.
The most cost effective powerhead option for recreational divers is the disposable powerhead. Disposable powerheads do not have their own firing pin which makes them a bit safer to use. Disposable powerheads use a spear shaft tip as a firing pin. They are designed for specific spear shaft thicknesses, so be aware of your equipment when making a purchase.
Most reusable powerheads have their own firing pin built in. These powerheads are usually designed for threaded spear shafts and need to be maintained better than disposable powerheads. Wash and dry reusable powerheads thoroughly after every trip or they will become rusted blocks of metal. They usually have multiple safeties built into them, and for god reason.
You need to be careful with powerheads that have their own firing pins. I recall an incident where a diver was storing one in the sleeve of their wetsuit. They got back on the boat and took off their suit. The powerhead fell onto the deck of the boat, fired, and went in and out of the divers leg and back into their chest. The diver made a full recovery, but still effectively shot themselves. Be aware of the risks.
People commercially spearfishing tend to favor reusable powerheads as the cost-benefit eventually makes itself up from the increased cost compared to disposable ones. That being said, Commercial spearfishers have a different intent. Commercial spearfishers aren’t using these to protect themselves. They are using them to harvest as many fish as possible as efficiently as possible as a job. Keep that in mind in your decision making process. Check out this video to see one in action.