Freediving and spearfishing fins are different from the traditional swimming fins in that their blades tend to be longer. This design choice helps the diver move faster through the water.
The standard spearfishing fin measures 31 to 38 inches, foot pocket excluded. With blades that are this long, more water is displaced with every kick, and propulsion is stronger. In turn, you get to cover more distance in less time and, therefore, use up less oxygen and energy. However, to choose the right spearfishing fins means more than considering the length of the blades.
We know now that spearfishing fins have longer blades than the conventional swimming fins, so that part’s a given. What isn’t known yet are these other elements that should factor into your fishing experience when using these fins.
More than anything else, you should consider how the fin fits you. Even a slight looseness may cause your feet to roll around the inside pocket, making kicking awkward and setting your feet up for blisters.
When the feet roll around the inside pockets, it creates interference in the transfer of power from your feet to the blade. Your kicking power won’t translate to the blade, causing you to lose efficiency as water spills through the sides of the twisted fin blades.
A too-tight foot pocket is another problem; this time, concerning comfort. A foot pocket that hugs too tightly may cause cramps. When sizing up this section, consider whether or not you’ll be wearing dive socks.
Blade stiffness is another priority when choosing a spearfishing fin. Using fins with the right stiffness helps improve dive time and maximize swimming efficiency. Generally, there are three types of stiffness available to divers: soft, medium, and hard. Your choice mostly depends on your body type.
If you’re a bigger person, for instance, you may require a stiffer fin to get you moving more efficiently in the water. If you’re an average-size adult human, you could require either soft or medium stiffness, depending on whether or not you’re top- or bottom-heavy.
If you are on the smaller side and decide to use stiff fins, you’d have to put in way more effort to get them to move you. You’d then be expending too much energy and oxygen, which could cause you to turn in the towel early. Alternatively, a big guy won’t be getting anywhere using soft fins no matter how strongly he kicks.
3. Material and Price
Included in our list of top considerations are material and price, which generally go hand-in-hand. The clear favorites when it comes to performance are fiberglass and carbon fiber, which are, unsurprisingly, also the most expensive ones. Both incorporate a two-part system consisting of the blade and rubber foot pocket.
You may purchase each component separately or as a package, so it pays to shop around. Good-quality fins have rails on the sides for better fin stability and for channeling water down the blade’s entire length. The blades are designed thicker around the toe’s base and become thinner towards the fin’s tail. This is known as the J-curve or hyperbolic curve, the most efficient fin Structure.
In top-of-the-line options, the foot pocket base should be stiff so that there is an easy transference of power from the foot to the blade. The rails on either side of the foot pocket should contribute to blade stiffness enough for optimal kicking. Some freedivers can be very specific about their fin blades’ foot pockets, so you may want to consider this part at length.
We’ve touched on fiberglass and carbon fiber briefly, but another material you may want to consider is plastic. Here’s a lowdown on what each has to offer.
Fiberglass fins are reactive and efficient. It is second only to carbon fiber in terms of overall quality and toughness. While carbon fiber is superior in performance, some spearfishers may prefer the fiberglass option due to its slightly more affordable price tag.
Carbon fiber offers the most expensive range of spearfishing fins on the market, and rightly so. They are the lightest and most reactive of all materials, so their performance is hard to eclipse even by their closest rival, fiberglass.
The least reactive and heaviest of all, plastic fins come with all sorts of drawbacks for the beginner spearfisher. That said, a decent pair should be tough enough to withstand some thrashing on the rocks.
Naturally, you will want to get your hands on either carbon fiber or fiberglass fins, but note that material comes after fit and stiffness in priority. A pair of plastic fins that’s the right size and stiffness for you would still outperform a carbon fiber model that’s a little too loose and a bit too stiff for your needs.