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Powerheads and Shark Shields - Risks and Uses

Powerheads and Shark Shields - Risks and Uses

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. 


Shark Shield

The Ocean Guardian Freedom 7 is more commonly called the “Shark Shield”. It passively emits an electric pulse that sharks find extremely uncomfortable to deter them from approaching within a few meters of a diver. The Freedom 7 is a great deterrent, but works only on 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 sharky 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 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 and destroying the seal. Once the powder in the round is wet, it 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 and the possible repercussions.

Powerheads do not go onto slip-tips.


Disposable Powerheads

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, and are designed for specific spear shaft thicknesses, so be aware of your equipment when making a purchase. 


Reusable  Powerheads 

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 good 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 the round went in and out of the diver's leg. The diver made a full recovery, but still effectively shot himself. Be aware of the risks.


Commercial Use

People commercially spearfishing tend to favor reusable powerheads because the cost-benefit eventually makes itself up from the increased price compared to disposable ones. That being said, Commercial spearfishermen have a different intent. Commercial spearfishermen aren’t using these to protect themselves. They are using them to keep predators away as they harvest as many fish as possible as efficiently as possible for a job. Keep that in mind in your decision making process. Check out this video to see one in action.
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