Epsealon Carbon Impulse Fins

[Sub37]

Hi! Anyone using the Epsealon Impulse carbon fins? I was about to go for 'Fins4U Pure Evolution' fins but Ian of freediveuk reviewed the Epsealons and found them even better than the Pure Evolutions. Any comments would be great! Thanks.

 

[Sub37]

Probably a paid review? Haven't found much info on the Epsealon Impulse fins, neither here nor on any other forums or sites...

 

[koriander]

Well...when he says that one of the best features of the fins are those "ridges" on the FP...well...it is like those small ailerons on very slow cars, they are for aesthetical purposes, you know that they are useles for the speed the car can reach. If you like those airelons, you buy them because you like them aesthetically, not because you know they work

And aesthetically, those "ridges" to me are very childdish. Of course, when he says that the water flows from the FP to the blade, the same childdish stuff to me. And when he says that he tried more fins and found these the best, I don´t believe him.

But it is only my opinion.

 

[koriander]

Hi! Anyone using the Epsealon Impulse carbon fins?

Forgot to say that I did not try these fins, sorry.

 

[SubSub]

Well...when he says that one of the best features of the fins are those "ridges" on the FP...well...it is like those small ailerons on very slow cars, they are for aesthetical purposes, you know that they are useles for the speed the car can reach. If you like those airelons, you buy them because you like them aesthetically, not because you know they work

And aesthetically, those "ridges" to me are very childdish. Of course, when he says that the water flows from the FP to the blade, the same childdish stuff to me. And when he says that he tried more fins and found these the best, I don´t believe him.

But it is only my opinion.

I can't dismiss it that easily. The comparsion with cars is irrelevant, water has very different dynamics and those ridges could very well catch some of te water flowing around the foot and guide it down the fin. I don't know if it would have a revolutionary effect on performance, but I can't say it would not have any effect at all.

 

[koriander]

@SubSub yes, the comparison with cars here is irrelevant , I only wrote it because the video put the same smile in my face that when I see a bad tunned car

Respect the "ridges"...there are a lot of water around you and the blades, I think you do not need to channel any water. Why would you have to channel water ? the water is replaced with water in the movement

 

[SubSub]

Yeah. In Sweden we call those "dekaltrimmade" which translates to something like sticker-tuned.

Anyhow... I'm no engineer but I'd go out on a limb here and say that the longer you can get the water to stream along the blade, thus transferrring power, the more you get out of your stroke. Maybe it also does something for the stability of the stroke?

Would be interesting to hear some input from someone with a bit of knowledge about hydro dynamics.

 

[koriander]

Hello, please excuse my english, I realized I made some mistakes in other posts.

I'd go out on a limb here

I dont understand that phrase, could you please rewrite that phrase? google translates something that I cannot put into context.

and say that the longer you can get the water to stream along the blade, thus transferrring power, the more you get out of your stroke.

I think that no matter what water you transfer the power to, channeled or not, while there is water. I mean, you need a power transfer materia for the energy from the blades be transferred.

Maybe it also does something for the stability of the stroke?

To me it is the most interesting point in this discussion, but remember that the blades are bending all the time, so ridges would be interesting in the last part of the blades, and not for channel water. That "ridges"... what want to stabilize? the ankles?

 

[ronscuba]

The theory: to move forward, push water directly back behind you. The rails keep the water moving back behind you vs. falling off to the side.

Stability: if the fin is twisting, then less water is being pushed behind you.

This is all theory. Need a hydrodynamics engineer to verify if true.

 

[koriander]

@ronscuba hi

The rails keep the water moving back behind you vs. falling off to the side.

Yes it is interesting. I don´t have any fins with rails but I can see that if you grab one by the foot pocket and you move it to the sides, the rails offers more resistance due to the higher section, which is I think is good, BUT I don´t know if that resistance becomes negligible with the kicks.
¿Is it a work about it? because I think the stability is due to the section of the rails that keeps the blade straight, not due to that the rails keep the water.
It is very visual when someone say to you "Look! the water flows in this way" moving the hand, but I don´t believe a word

 

[SubSub]

I dont understand that phrase, could you please rewrite that phrase? google translates something that I cannot put into context.

Something like; I might be the only one with this opinion.

I think that no matter what water you transfer the power to, channeled or not, while there is water. I mean, you need a power transfer materia for the energy from the blades be transferred.

To me it is the most interesting point in this discussion, but remember that the blades are bending all the time, so ridges would be interesting in the last part of the blades, and not for channel water. That "ridges"... what want to stabilize? the ankles?

It's a question of how much surface that can convert energy from the kick to forward propulsion.

Normally the foot part of the fin does not catch the water flowing around it, it has more of a cutting edge. Seen to the pictures, this fin has a broader area around the foot and the channel might catch and guide some of the water, that would otherwise just pass the fin, and channel it down over the fin.

 

[koriander]

Something like; I might be the only one with this opinion.

Ah ok thanks

It's a question of how much surface that can convert energy from the kick to forward propulsion.

Normally the foot part of the fin does not catch the water flowing around it, it has more of a cutting edge. Seen to the pictures, this fin has a broader area around the foot and the channel might catch and guide some of the water, that would otherwise just pass the fin, and channel it down over the fin.

I see your point. So the caught and redirected water down over the fin means that the fin has more water on the surface, and due to this, more fluid to transfer energy?
Mmm...I think that the caught and redirected water has to displace other water to make room...how is possible to load more water in the same area?

 

[koriander]

In fact, I even doubt that those "ridges"are of the proper size...

 

[ronscuba]

I see your point. So the caught and redirected water down over the fin means that the fin has more water on the surface, and due to this, more fluid to transfer energy?
Mmm...I think that the caught and redirected water has to displace other water to make room...how is possible to load more water in the same area?

Think of this analogy. You are standing inches in front of a wall. You reach out with your hands and push against the wall. Your body moves away from the wall. The wall is a still fixed object.

Water is not a fixed object, but it does have resistance. If water had a lot of resistance, it would act like a fixed object. Push yourself against water and you move forward. The more water you move against, the more resistance, the more it acts like a fixed object, the more forward you move. Kicking is like pushing against water.

Add in how fast and frequently you do this, the faster you move forward.

 

[koriander]

Think of this analogy. You are standing inches in front of a wall. You reach out with your hands and push against the wall. Your body moves away from the wall. The wall is a still fixed object.

Water is not a fixed object, but it does have resistance. If water had a lot of resistance, it would act like a fixed object. Push yourself against water and you move forward. The more water you move against, the more resistance, the more it acts like a fixed object, the more forward you move. Kicking is like pushing against water.

Add in how fast and frequently you do this, the faster you move forward.

Hmm I think there is a misunderstanding. Please correct me if I am wrong, ¿you are explaining how action and reaction works? please do not read this as an offense, it is only to cut the misunderstanding as soon as possible. I think it is a misunderstanding because what you quote in your post is related to the water redirected from those "ridges" down over the blade, not the water that is over the blade

If it is not a misunderstanding, I will work to try to explain myself again ( and the times needed)

 

[koriander]

Ok I was reading an older version of your post, sorry.

Think of this analogy. You are standing inches in front of a wall. You reach out with your hands and push against the wall. Your body moves away from the wall.

Yes, action and reaction, I agree

Water is not a fixed object, but it does have resistance. If water had a lot of resistance, it would act like a fixed object.

I agree.

The more water you move against, the more resistance, the more it acts like a fixed object, the more forward you move.

I think you are wrong here...that works with gases, the density in gases changes with presure. If you kick like hell against water you move faster but not because the water becomes more hard, the water has very little compressibility.

Add in how fast and frequently you do this, the faster you move forward.

The finning, I agree, but not because the harder the water become with "pressure" but the more water you displace, due to action and reaction.

Please let me know your thoughts about it

 

[ronscuba]

I don't have any formal education of water dynamics. Just thinking out loud on what seems logical to me.

Your basic question is what is the physics explanation of how something moves forward in water ? Question seems similar to what makes a plane move forward. One moves forward against water, the other moves forward against air.

 

[koriander]

I don't have any formal education of water dynamics. Just thinking out loud on what seems logical to me.

Your basic question is what is the physics explanation of how something moves forward in water ?

Yes sorry, it is how octopuses moves, ejecting water from the siphon. And like you write, you move the wall and the wall moves you.

 

[ronscuba]

Applying force backwards which then moves us forward ?

You mention an octopus ejecting water which moves it forward. If the octopus ejects more water isn't that in an increase in force that will propel if forward faster ? If so, a fin that moves more water will propel the diver forward faster ?

 

[koriander]

Applying force backwards which then moves us forward ?

Yes, it is how they teach it to me, but I am not an expert in water dynamics, only thinking like you.