Why Jet Fins???

[boomx5]

NaCL H2O Boy once bubbled...
I understand where you are going with your analogy,

As a cyclist, what is the largest muscle in your body?

 

[NaCL H2O Boy]

Dan Gibson once bubbled...
Of course the opposite could also be said about people who claim Jet Fins don't work as well as split fins. The problem when comparing the two fins is that most people can't frog kick worth a darn. It is not a huge kick as most people will lead you to believe. It is mostly from the ankles and lower leg. Modified is even smaller and uses very little ankle movement.

I've tried using the frog kick with my splits, and while I was able to do it, it wasn't as effective as the flutter. Now if I actually spent some time working on it to optimize it for splits, I'm sure it could be just as effective. The problem is that a lot people are sloppy in most kicking techniques and it keeps them from maximizing the potential of their equipment. Then again, this isn't synchronized swimming we are talking about. Most people just want to get out there and dive, and explore.

 

[NaCL H2O Boy]

boomx5 once bubbled...


As a cyclist, what is the largest muscle in your body?

The largest or strongest?

 

[Warren_L]

Largest and strongest - Quadracepts. By far.

 

[NaCL H2O Boy]

Largest is the gluteous. The strongest muscle is up for much debate. Most actually believe it is the tongue, while some say the heart, and others say the calf muscle.

 

[Warren_L]

No jokes about a big butt, but I think my glutes aren't as big as my quads, and definitely not as strong.

 

[NaCL H2O Boy]

warren_l once bubbled...
No jokes about a big butt, but I think my glutes aren't as big as my quads, and definitely not as strong.

My quads used to be a lot bigger, but I've been off the bike for a long time. Too long.

 

[Warren_L]

Well, both are actually an integral part of cycling, as they are the two major muscles that contribute to a down stroke. Up stroke I would argue that it would be primarily the quads and hip flexors.

 

[Dive Source]

MikeR once bubbled...


Simple-airplanes, subs, cars etc. can be built identical. No two human bodies are identical. Stong, weak, thin, thick. They all have different results with the same fin. Its like having 1 propeller for every airplane made. It will work great on some not at all on others.

Sac rate also needs to be taken into account when testing a fin. Only humans can provide that.

These are excellent points for discussion and bring up more questions in my mind:

- I'm not sure if actually matters if the human bodies are different as they are just the motor. The propulusion device ( fin or propeller) is attached to the human motor and should be sized accordingly.

-Choosing a propeller for a plane or a boat takes many factors into account all of which directly effect performance and fuel economy of the motor they are attached to (once again we see design effecting efficiency and results that can be measured)

-Perhaps consideration should be given to the possibility that certain fin types should not be used on certain body types or leg sizes? Many different propellers are made for different size planes or boats so fins should be sized more closely to body size to achieve efficiancy.

It's been my experiance it fitting fins to people that if you are not carefull you can put too big a fin on a person or too small a fin - both of which effect it's efficiency.

- SAC rate is an important consideration in testing fins, but isn't it just a result of energy used by the diver? I.E. If you are working harder with a fin that is less efficient then you breath more?

Finally the most important factor that I believe affects efficiency is technique. Every fin made will have an optimal way to use it and human beings have difficulty repeating experiments exactly.

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PS - NaCL H2O Boy you impress the heck out of me with your tests !

 

[Uncle Pug]

Simple. They are the fin of choice for those who want precise control.

Stopping abruptly, turning sharply and backing up require traction only a paddle fin affords.

Most airplanes don't excel in those maneuvers...nor do propeller fins.