Marine Conservation

Understanding your dive equipment: Fins

Posted: September 30, 2020

Ever wondered what to look for with a SCUBA fin? Trying to work out what to purchase before your first dive or diving holiday? Want to know more before you join a diving program here in the Seychelles? Hopefully within this blog we explain the benefits of the different fins, parts of, and what they are best for to give you a chance of getting the right piece of kit for you.

The fin is split into 3 areas. The blade, foot pocket, and heel strap. Each area differs on different fins and has it benefits for doing so. Let’s first look at the blades…

Split fins and hinged fins

Split fins came about after looking at nature and how different wildlife moved through water. They realised that split fins are great at completing a basic fin kick of the up and down movement (not a frog kick) due to the split fins angling inwards helping propel the diver. This fin is great for anyone who needs to conserve energy or take strain off their knees or legs due to their efficiency. The hinged fin has a separation between the foot pocket and the blade allowing further movement of the blade when fin kicking again allowing for greater efficiency.

Paddle style fin and channel fins

Moves the water out of the way and normally has a ridged material around the edges and in the middle to give you some support and then between those sections a more flexible material to have a bit of give with the fin to help move the water out of the way. It is an excellent entry fin if you are not sure what you want, what they feel like, and are normally quite lightweight for when you go travelling. If you want to look at the next step up from a paddle fin it would be a channel fin. They are very similar to the paddle fin in many ways with having the rigidness along the outside to move the energy all the way through the fin. But with smaller channels through the center of the fin, it allows a bit more flexibility and therefore slightly more efficient.

Vented fin / Jet fin

These fins have a vent within the blade just before the foot pocket. The idea is that it allows the water to pass through that area moving it in the direction of travel. They’re normally quite short and you would think that they would be light weight due to a shorter fin. But most are quite dense and weigh more than the average fin. Due to the shortness of them, they are preferred by more technical divers. I personally own a pair (not a technical diver) but I feel that these, compared to my hinged fins, allow much greater movement with much less energy needed while on survey dives. I also find them really useful when entering wrecks due to their size.

Foot pockets

With the foot pockets you have the open heels and the closed foot pocket. The open heel is used if you want to wear a dive boot/shoe or wear a dry suit. This is normally suited to colder water temperatures as you want to keep the feet warm. I actually dive with open heels due to the fin I have chosen but I also enjoy diving in boots and due to the walk I need to complete for the dives, most who join the marine conservation and research base at Cap Ternay also wear boots. Closed foot pockets are great if you are happy to dive barefoot or with a thin dive sock on to prevent rubbing. Aimed for warmer climates, they are a good lightweight solution to the open heel fin.

Heel straps – comfort, size, and fitting!

These are key for fitting your fin and making sure that it is comfortable. It allows you to wear different thickness boots with your fins depending on the environment you are in and can even (if you are nice enough) allow you to swap and change fins with a friend and or dive buddy to test other fins out as well.

A ratchet strap

It is the simple and more commonly used type of heel strap. It has a simple one way locking system on either end of the strap to tighten it and if you need to loosen the strap there is an easy release button. You can unclip them and if they were to break it’s normally quite easy to find replacements as most have a similar connection to the actual fin. However, the downside to a strap like this, from my own previous experience is that I have seen divers struggle to tighten and loosen the straps after kitting up. It can also become troublesome if you are on a smaller dive boat or in rougher conditions.

Bungee / Metal spring heel strap

It is clipped to your fin and is quite reliable underwater. Due to it being a bungee mechanism if there was any compression of your dive boots at depth it would keep the foot nice and secure within its pocket. The benefits of this is that they are really easy to put on and take off. The strap itself is made to last but, from what I have seen of certain straps, they can wear down quite quickly in certain environments. For example, here in the Seychelles, I had the strap wear down and begin to crack after 3 months of use and exposure to the environment here. The flip side of that, it was easy to find a replacement strap and to change them out.

The metal spring heel strap has all the benefits of the bungee heel strap but the chance of it cracking or damaging in constant use is reduced due to it being metal. Even if something was to happen to it, again, it is easily replaceable with a similar metal strap. All you need is a screwdriver.

How does all of this matter when choosing a fin?

It doesn’t really. Well, that’s not quite true. You might have an idea of what diving you want to do? What conditions are you diving in? What purpose are you diving for? And answering these questions may let you work out in greater detail what you want. If you have knee or leg issues I would not consider a high density vented/jet fin. If it’s my first dive (unless, somehow, it was the most comfortable) I wouldn’t jump at the most expensive fin but maybe look at a simple blade or channel fin so you can learn to dive effectively and understand your own dive style. In the end, the thing that comes out on top is comfort, and maybe cost, but mostly comfort. Is that fin comfortable for you? Were you able to enjoy your dive without thinking about the fin rubbing, causing you cramp, or pain? If so then you might be onto a winner. The only thing I would say is try on as many as possible. Speak to friends and family. Speak to your local dive club for advice. Have a chat with experts at your local dive shop. Email the big retailers online. You will find the diving community will help you out a lot and are more than happy to.