Fins and manoeuvrability

[REVAN]

I've been following this thread. Y'all have got me really thinking about trying some freedive fins.

Looking at the Mako fins, the fixed blade ones are $68 and the replaceable blades ones are $90. The fixed blades are thermoplastic where the replaceable blades are a fiberglass blend blade.

Dan (or anyone else), have any thoughts on these? It seems like $22 extra is well worth it, if the competition fins are better - even if it's just a very small difference. As a concept, I like the idea that if I find I really like them, I would have the option to replace the blades later, whether it's to "upgrade" or simply replace worn ones.

And you say these fins would still work well for frog kicks and back kicks (in open water)?

I agree with Dan. The fiberglass is probably worth the extra cost. My brother had bought a cheap pair of plastic freedive fins ("Persistant" brand I think, at about $50). They really didn't feel very good to me. Even after I take into account that the foot pockets were too large for me, I think the blade was just not made right. It is hard to get a blade that has the right flex ratios along its length, and I think these were just too stiff out near the end of the fin blade.

The DiveRs I used in Hawaii were MASSIVELY better. A couple years ago, I started experimenting and making my own bi-fins using composite materials and they are now feeling pretty awesome too (after making about 15 different variations). What I've learned is that there are details in the design that really matter. It is not just the case of "this fin is fiberglass and therefore it rocks" and "these are plastic and so it is bad". It very much matters what is done with that fiberglass or that plastic material in the design. It really needs to get pretty soft and floppy out near the end of the fin, even if it is a fairly 'hard' fin. My advice is to find something with a lot of taper to the stiffness profile.

I'm also finding that scuba diving favors a harder fin blade than freediving. Having air available such that you can afford to work a little harder, coupled with the increased drag of the scuba equipment and often shorter durations in the water makes the stiffer fin desirable for scuba. So, look for a medium or a hard fin; avoid soft for scuba. However, the harder fin blade raises the requirement for a better fitting foot pocket so that it doesn't cramp you up. That's one more thing to think about.

 

[Eric Sedletzky]

If you use amatuers with 30 to 100 dives that have horrible form and are out of shape to perform performance tests to see what kind of fins they like and what works best for them, you'll get split fins.
I would imagine this had a lot to do with their reason for being.
If they where the all powerful and awesome fin they were originally touted to be you'd see every competitive freediver in the world using them.
Do you see freedivers using them???

 

[67macoshark]

I agree that I am nothing like the target demo for the high volume new fin purchases...but testing is another matter.You can't employ testers that can't kick properly--and dont have any sense of what's good and bad in a fin. All they really know is whether their own defective kick style works with a given fin, or not. What you are missing, is that if you had ten of these rank novices, there could easily be 10 different types of defective kick shapes.A better plan, would be to have only testers that understand exactly the right kick shape each fin requires....and then if you are a novice that buys a fin they say good things about, you know it is possible you may need an instructor or mentor( free for a mentor) to show you the right kick stroke, and help you attain it in the next 2 or three pool or ocean dives.

The testers in the evaluation that John linked were not novices. They were all male, dive pros or instructors, 3 to 15 years experience, and self-reported 100 hrs/yr of diving. They also appear to be in good shape from the data provided.One interesting point was in the discussion that spoke to the diver's perception of the fins effectiveness. "The divers invariably ranked the stiff fins as the best, and the flexible fins as the worst, which did not correlate with the objective evaluation of these fins."

 

[danvolker]

The testers in the evaluation that John linked were not novices. They were all male, dive pros or instructors, 3 to 15 years experience, and self-reported 100 hrs/yr of diving. They also appear to be in good shape from the data provided.One interesting point was in the discussion that spoke to the diver's perception of the fins effectiveness. "The divers invariably ranked the stiff fins as the best, and the flexible fins as the worst, which did not correlate with the objective evaluation of these fins."

First, thanks to John Ratliff for this excellent example of the science of one of the better testing scenarios I have ever looked at.
Even though it is far better than one done by a print rag, I see major problems with too many important variables that are not even considered....variables that completely invalidate any value the test could have.....

And i quote
" Ten male diverswere studied. The divers were all SCUBA certified instructors or professional divers and hadbeen diving for between 3-15 years and self-reported 100 hrs/yr of diving. "

3 years of 100 hours of diving each year..lets call this 50 dives in a year.....but this could have been 75 hours in a pool, in a year, which does not qualify as diving 100 hours in my mind.

I did not read this closely enough when I skimmed through the piece earlier....I admit I did not notice the "per year" part, but the issue is still not resolved in any sense....We have no idea if these guys have any sense of correct kick shape for each fin, or even if they are competent with kick shapes for the fins they normally use.


To make this closer to having possible validity......Lets create the following changes:

1. 10 top competitive 130 to 200 foot freedivers to test all fins for flutter kick and dolphin kick...and frog kick. These guys would be experts at the most efficient kick shapes for these kicks, and in getting the most out of any fin....
2. 10 top cave diving instructors to test the same fins for frog kick, reverse kick, helicopters, and modified flutter. These guys would be experts at the most efficient kick shapes for these kicks, and in getting the most out of any fin....
3. Orientation for all of these divers as to the fin manufacturers suggestion as to OPTIMAL KICK SHAPES for each fin.
4. Blade stiffness for each fin matched to each testing diver wherever multiple stiffnesses are available.

This would be a much better start.

 

[lowviz]

Update.

Both my Mako Freedive Hunter fins and my Freedom Plate came today. Amazing engineering in both.

Fins: First, without a doubt, the most comfortable fin I have ever worn. They fit like an old pair of hiking shoes and bend in all the right places. With the neoprene socks, they are a bit of a challenge to get on. However, they feel like an extension of my leg once I get them on. Not tight but no wiggle, extremely comfortable, the bottom of the foot pocket points upward so that the blade is pointing a bit downward.

When I push the blade tips down and away, the fin bends in a fairly even bend except for the first third nearest the blade tip. When I pull the blade tips up towards me, the fin bends mostly in the middle third with the fin tips resisting any bend due to two small ribs that get progressively stronger (higher) near the fin tips. The fin's flex in either direction is quite different. The bent blade has a surprising spring in either direction when released, nothing at all like any of my SCUBA fins. I'm glad I started with this fin (Thanks Dano), after I "get it" then I will be able to appreciate fiberglass and beyond. Just me and how I like to do things, others may have a different experience. I'll take the long way around.

Plate: The Freedom Plate is sheer bliss! I couldn't quite figure out where it was supposed to go on my back so I held it up against me and slid it up and down. There is one and only one place it fits, half inch either way starts to feel wrong. I was thinking that placing it there would make the tank ride at an angle. Just noticed that the tank rails are angled so that the tank ends up in the proper configuration. It is a damn shame that these aren't available anymore.

Wing: *Sigh* The OMS 32# is just too big for this minimalist application. It will probably ruin the test with drag. The Oxycheq mach V 18# wing looks perfect...

I'll let you know more when I get this rig wet, next few days look unlikely due to storms. I'm starting to wander a bit too far from the OP so I'll start a new thread when I do.

 

[Bob DBF]

Also with freedive fins there is a personal factor in how well any particiluar fin works for you. A buddy got fed up with the fins he bought and moved on to another set. On an outing he asked me to try the fins, they matched the frequency and amplitude of my kick, I loved them. I tried to give them back after the dive, but he wouldn't take them, said "I watched you with them and they belong to you"

I normally use jet fins on SCUBA because Farrallon doesn't make fins anymore, and the Mares almost got me killed. I use the freedive fins on SCUBA occationally, but the length of the fins and shore dives don't mix well here.


Bob

 

[Eric Sedletzky]

The Freedom Plate is sheer bliss!.... Just noticed that the tank rails are angled so that the tank ends up in the proper configuration. It is a damn shame that these aren't available anymore.

If you understand the current general diving population and what its made up of you'd see that 98% of divers these days don't have a clue about streamlining, hydrodynamics, gear choices, etc., and many have no imagination to understand anything beyond what they've been programmed to believe.
This goes for everything from basic OW vacation divers who buy everything their LDS tells them they need, or it could be a group that's told they need drysuits, conventional plates, can lights, scooters, and the rest of the stuff.
That leaves a very microscopically thin piece of pie for something like my plate to try and find a place to fit in.
The only people I found that really understand the simplicity and obvious ergonomic advantage are old school divers that might have learned using a plastic or metal back pack from back in the day. They seem to know right away what it is and how it's going to work. There are some new divers too that DO have imaginations and enough intelligence to see things and figure things out. They are the ones that aren't brainwashed (yet) into any mainstream cattle drive or specific school of diving to the point they can't see anything else but the way they've been programmed. But they are very far and few between.
Most divers are very scared little people with many fears and it's a very long arduous agonizing process to make them change something or try something new.
You have no idea how many people simply can't do a beach demo and throw on a new rig and take it for a spin because it will mean they would have try something new, and in their minds they could die because they didn't take a specialty class for it and don't have the specific "C" card....Something along the lines of how Sheldon Cooper of Big Bang Theory would act... I'm serious!

Many divers are also not on the internet which means I have no access to them, unless they local or a friend of a friend. Dive shops won't carry it because there's no markup structured in, plus they are all on the main track with conventional gear, and it's just too oddball and homemade.

So all this after 11 years now of repeatedly slamming my head into a brick wall expecting a different result besides a splitting head ache, I have to step back at some point and look at the overall situation and ask, "Is it going to work enough to sustain a business?"
And the sad answer is "Probably not".
The upside is, the people who have them absolutely love them, but the problem is there's just not enough of those people.

 

[JohnnyC]

If you understand the current general diving population and what its made up of you'd see that 98% of divers these days don't have a clue about streamlining, hydrodynamics, gear choices, etc., and many have no imagination to understand anything beyond what they've been programmed to believe.
This goes for everything from basic OW vacation divers who buy everything their LDS tells them they need, or it could be a group that's told they need drysuits, conventional plates, can lights, scooters, and the rest of the stuff.
That leaves a very microscopically thin piece of pie for something like my plate to try and find a place to fit in.
The only people I found that really understand the simplicity and obvious ergonomic advantage are old school divers that might have learned using a plastic or metal back pack from back in the day. They seem to know right away what it is and how it's going to work. There are some new divers too that DO have imaginations and enough intelligence to see things and figure things out. They are the ones that aren't brainwashed (yet) into any mainstream cattle drive or specific school of diving to the point they can't see anything else but the way they've been programmed. But they are very far and few between.
Most divers are very scared little people with many fears and it's a very long arduous agonizing process to make them change something or try something new.
You have no idea how many people simply can't do a beach demo and throw on a new rig and take it for a spin because it will mean they would have try something new, and in their minds they could die because they didn't take a specialty class for it and don't have the specific "C" card....Something along the lines of how Sheldon Cooper of Big Bang Theory would act... I'm serious!

Many divers are also not on the internet which means I have no access to them, unless they local or a friend of a friend. Dive shops won't carry it because there's no markup structured in, plus they are all on the main track with conventional gear, and it's just too oddball and homemade.

So all this after 11 years now of repeatedly slamming my head into a brick wall expecting a different result besides a splitting head ache, I have to step back at some point and look at the overall situation and ask, "Is it going to work enough to sustain a business?"
And the sad answer is "Probably not".
The upside is, the people who have them absolutely love them, but the problem is there's just not enough of those people.

It's a shame, I'd really like to pick one up down the road. I think it would make a fantastic travel rig. Right now I just swap double to singles wings, and take my normal SS plate, d-rings, bungees and all. It's not ideal. I end up having more stuff than necessary when I'm diving recreational singles, but can't be arsed to unthread the harness to get rid of all the unnecessary stuff every time I want to fall off a boat and piddle around.

 

[lowviz]

... in their minds they could die because they didn't take a specialty class for it and don't have the specific "C" card....Something along the lines of how Sheldon Cooper of Big Bang Theory would act...

I owe you for one hell of a good laugh!

Yes, indeed. Sheldon would immediately "get it" and we all can see that scene playing in our heads when he is handed a Freedom Plate and asked to actually put it on. OMG, the inner conflict!

Freaking perfect analogy.

... Many divers are also not on the internet which means I have no access to them, unless they local or a friend of a friend. Dive shops won't carry it because there's no markup structured in, plus they are all on the main track with conventional gear, and it's just too oddball and homemade.

Neither. Oddball, show one to somebody who makes prosthetics. Homemade, no extremely well made.

So all this after 11 years now of repeatedly slamming my head into a brick wall expecting a different result besides a splitting head ache, I have to step back at some point and look at the overall situation and ask, "Is it going to work enough to sustain a business?"
And the sad answer is "Probably not".

When I was in electronics, I worked with an entrepreneur who had a lot of irons in the fire. He showed me his business model:

The Incredible Secret Money Machine

The upside is, the people who have them absolutely love them, but the problem is there's just not enough of those people.

Not enough to sustain a business, but way more than enough to generate another "nickel stream" and keep your brainchild alive.

Suggestion: Run a batch operation. Take the materials cost upfront when you get enough orders and then final payments as each becomes ready for shipment.

 

[gkrane]

To make this closer to having possible validity......Lets create the following changes:

1. 10 top competitive 130 to 200 foot freedivers to test all fins for flutter kick and dolphin kick...and frog kick. These guys would be experts at the most efficient kick shapes for these kicks, and in getting the most out of any fin....
2. 10 top cave diving instructors to test the same fins for frog kick, reverse kick, helicopters, and modified flutter. These guys would be experts at the most efficient kick shapes for these kicks, and in getting the most out of any fin....
3. Orientation for all of these divers as to the fin manufacturers suggestion as to OPTIMAL KICK SHAPES for each fin.
4. Blade stiffness for each fin matched to each testing diver wherever multiple stiffnesses are available.

This would be a much better start.

How do you propose to get this elite group together to test fins? I would imagine they have already tested and found what works for them. There is the great possibility that none of them wish to play test dummy for no compensation. Also, with the parameters you set I think we may be straying away from recreational scuba and more to the "elite individually tailored" market. This sort of derails the experiment since I thought the end goal was to have the top fin manufacturers start producing better fins that encompass recent technological advances. I'm not sure if the general public is ready to buy a fin based on optimal kick shape, and the general public is where the biggest piece of the sales pie is for the manufacturers.