Why Our Blades Have A 30 Degree Heel And A Rounded Tip
Our 30 degree heel means less knee bend on the surface and less load on your shins and knees, and the rounded tip gives more thrust for its length.
One of the questions we get asked a lot is about the design features of a DiveR fin. Two stand out, the angle in the heel and the rounded tip. This short video covers both, and the notes below explain what each one does for you in the water.
The 30 Degree Heel
What makes a DiveR fin is the 30 degree angle in the heel. DiveR was the first to present fins with such an extreme angle, and the others followed.
The heel is the end of the blade that sits in the foot pocket. On a flatter blade, the blade carries on in much the same line as the sole of your foot. Ours has a 30 degree angle built in at that end, so the blade already sits at an angle to your foot before you start kicking.
In the video the blade is held side-on at chest height with a finger on the bend, then tilted to show where it sits when you are on the surface.
The angle is there for your posture in the water. When you are swimming on the surface you do not have to bend your knees as much, because the angle is already built into the blade. With a lesser angle blade you miss out on 25 to 30 degrees of kick angle.
A lot of diving happens on the surface. You breathe up there between dives, and you fin along it to the next spot. All of those kicks are made with your body lying flat in the water, which is the position the angle is built for.
Easier On Shins And Knees
Correct posture changes where the work goes. A 30 degree heel is much easier on the shins and knees, and it transfers the load from the fin blade through the quadriceps.
The quadriceps are the big muscles at the front of your thigh, and some of the largest in your body. A long fin kick is usually taught from the hip with the legs fairly straight, so the thighs do the driving. Bending hard at the knee on every stroke moves that work onto smaller joints and muscles.
If you finish long sessions with sore shins or knees, the angle of your blades is one thing to look at.
The Rounded Tip
You will see many fins cut with a fishtail design. Most high-speed fish have a fishtail, and they move quite fast in the water.
Humans do not move very fast in the water. We are more like a groper, and all gropers have a rounded tail. If you have seen one on the reef, you will know they are big, slow fish.
A rounded tip is much more stable in the water, and you get more thrust for the length of the fin.
Choosing A Blade
The blade in the video is a medium carbon blade in the wild red octopus design. Medium is the flex and carbon is the fibre, and you choose both alongside the design.
Fibre is the bigger decision. Composite is the durable blade for rock hopping and divers new to the sport. Carbon is a lot lighter and more responsive. Innegra carbon is the least fatiguing blade we make. Our guide to composite, carbon and Innegra carbon goes through each one.
The heel sits inside the foot pocket, so the pocket matters too. See which foot pockets fit our blades for the pockets and sizing, or go straight to our fin collection.