Long Tail

[MarkF]

Making a long tail, considerations.
How long is to long?
how wide a fluke "Caudal"?
how long a fin?
Does it have to be harder to swim than a short tail?:confused:

Mine is a combination H2o, Trident True and PearlieMae with a squish of Me in it so your welcome to blow bubbles in anywhere.
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[MarkF]

The observations of Winter the dolphin swimming with her prosthetic tail shows that a simple flexure between the wearer and the fin is enough to swim, just like H2o. “Oh - Seems Winter only gets to wear it for shows.”
http://www.seewinter.com/animals-exhibits/meet-animals/live-web-cams-0

This simple design made me wonder what’s the point of the muscles to move the fin. It seems you can stiffen to swim with more intensity or less. So with just a flexure the amount of effort is higher the longer the tail and the stiffer the flexure - all the time!
The cool side fins are stability and braking and generally not floppy when the the Merfolk is still.
How long is long and what looks right? So this is what I considered when designing this tail. As for the look I can’t imagine making anything better than what’s already out there. Now collecting the pieces for the bones of the final tail.

[MarkF]

The first thing I had to control from the first attempt was a leg brace improvement. The old one's problem was twist, seems Mako Island found the same issue and changed from a round rod to a flat bar. So from the bottom of the feet to the fin is a fiberglass bar. Fiberglass has a great resistance to fatigue and that why cars now are using flat epoxy fiberglass for leaf springs. Also fishing pole and long antennas are fiberglass.
How long - I've found the distance from the hip joint to the knee is about the same as the knee to the ankle. I'm adding that same distance from the ankle to the pivot in the tail fin. "I keep wanting to say caudal"

[Echidna]

Interesting.
Maybe there will be a whole new approach to swimming with fins one day.

I thought about it myself when reading about my favourite species (Mosasaurs).
Recent research revealed Mosasaurs did NOT swim in a wiggling movement (like eels or dolphinkick), but held their bodies stiff and getting great propulsion moving their caudal fins alone (like sharks).

It made me wonder if the dolphinkick, as graceful and elegant it may look, is really the most efficient locomotion method.
It obviously depends on the fluke- just look how efficient dolphins and whale move with that principle- but maybe there's something better for us. eh? :p

[MarkF]

As I envision it. I'm only keeping your foot pivot at the same place in the tail. On a normal tail the ankle is the pivot point, I'm creating a way to keep the tail fin pivoting as if the length was short. On a normal tail you move your foot and the fin moves at the base of the tail. On mine the fin pivot is 15" lower and from the outside the fin still moves from the bottom most point of the tail.
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You still porpoise to swim.

[MarkF]

Tail Fin / Fluke / Caudal is not in the drawing as I haven't made my mind up on it yet. I have 3 screws that hold it in a clamp. In a couple weeks when this part's done I can try it and switch different size primitive flukes to see what feels right. Then I'll go crazy with style. I do like the dragon style.
I think what the picture doesn't show is your foot can move like it does normally and the caudal at the bottoms moves with it.

[MarkF]

One part that does not reveal itself in this picture, when you push your heels sideways it will lift and lower the side fins. I looking forward to trying a couple fin styles before silicone and assembling the side fins.

[Echidna]

I'm not sure I can envision it (probably because I'm tired and foggy), but it sounds interesting.
Let us know if it was a success once you build it!

[Trident True]

Sounds interesting. in one of the pics I found of mako Mermaids tails, the top of the heel has a spring which is attached to the top of the foot pocket. so in this instance the actors have to bend their legs in order to swim. as they push down the spring moves up and down. Now i can understand that turning would be difficult as it really only moves up and down not side to side as well. so this is what Im attempting to do on my other tail, Hopefully but attempting to make it more flexible due to turning. As for the Length the longer it is the more difficult it will be to maneuver and that's something I deff know off. if I attempt the Long tail my extension will be no longer than 12'' from the bottom of the feet.

[Mermaid Kassandra]

You can ask to jynxie she made extended tails like the one for H2O!

[Marinus Mortimer]

How is this project coming along MarkF? Im really interested in seeing the final product, best of luck.

[Mermaid Lieke]

This project is so interesting! I'm pulling up a seat.

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[Ilyena]

Guys please take in mind when the thread was last posted in. Almost 2 years ago.

[Marinus Mortimer]

Yes true, I hope he continued his project cause it holds great potential. I would start a thread on my extended tail design which i will be completing by the end of this year I'm currently saving up the amount of money i need to build the tail, once i have by budget bucket filled ill buy all the materials, I've read that silicone haves a limited green time so i wont buy it until I'm sure i can begin, ill definitely will be making a thread on my progress for all to follow.

[MarkF]

Got your message Merman Marinus, tonight I'll give you the slippery details.

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[Trident True]

yes, its not easy to create the Extension. I'm still trying, but have finally came up with an idea that will work 3rd attempt. Merman Marinus creating this piece isn't as easy as you may think I wish you luck. the Hardest thing is the mechanics of it, then bringing those ideas from paper to reality.

[MarkF]

Hey Mers and Merfets, I’ll say in the quest for the right long tail, it’s a complex road.
My dilemma was challenged at three points.
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1st The Fluke/Caudal hinge torsional strains keep overcoming the hinge. I was trying to use lightweight materials, when abusing the fluke it would break “Standing on it”. There’s the issue of neutrally buoyant “That’s big!”37838
2nd I want it to be easy to reproduce. The entire design includes the side fins to be controllable, I mean being able to lower or raise them. Originally the tail fluke would open or close and move one side up and the other side of the tail down, “maybe another time, need just to finish.”
I feel Merfolk in the preforming arts should be able to have more “Ah!” effect than the general enthusiast. To be able to move fins on demand would add to the magic. For instance when your favorite pet fish is unhappy they lower their fins and when happy they raise them.
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Lastly, OMG! Once the components were coming together in these trials the family was going freaky. I mean un-rational. I was getting calls from out of state family members – OMG! Recently A merfolk living at home had his dad do the same crazy response to his desire to join the pod. That pissed me off so back to the design build.
Any negative buoyancy from hinges, braces, cushions has to be offset with little containers of air to be buoyant in the tail. Because the tail has places where your legs aren’t and you don’t want to just fill it with silicone because it has to be flexible. Humm? How to deal with the void.
Remember when you see my pics they are done for me to think through its operations and stresses. You are welcome to ask questions though.
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So where am I, now attempt 5! I haven't even got silicone on my fingers yet.

[MarkF]

I've ordered a camera mount for this next set of embarrassing moments.

[Mermaid Alea]

I am glad you are still pursuing this! How would the wearer make the fins move individually? Or would someone be hidden somewhere with a controller and they would be making the fins move? I do love the idea of say a spikey dorsal fin raising up and fanning out as a mer comes quickly up to the glass to surprise people.

[MarkF]

My goal is all mechanical,
There is a pivot at the ankles, for the first version it's goes through side to side and the fin is fairly traditional. For version two the rays in the fin are separate like toes. The foot pads are not connected together and when you move one foot down, that side of the fin goes down. There is a mesh between the rays so they articulate properly.
Does that make sense?

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[MarkF]

Oh, as far as side fins there is a pivot under the toes so when you flex your heels sideways the spines lay upward or downward. I'm thinking when extended they would create drag.
I'm not sure if I'd make the lock in place or be held as long as you are flexing. Although I don't know how much effort it would take to hold them up. I know how to create them I want to get the basics going first.
A wise mermaid warmed me to not create so much that I'd never could finish.

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[Marinus Mortimer]

Im not going for very impressive mechanical things for my tail but props to Mark when you finish this project it is going to be the most realistic tail in the Ocean River or Lake u swim in.

For my extension im going with lexan as you can see in the picture im trying to avoid the overall tail from having a downwards angle after the feet so the triangular lexan base or footplate will avoid that weird bend, i dont know but i dont want it to look like the Hook move tails (dont get me wrong i love them) i want the tails to be straight the only bend us when i move. Anyways hope yall can understand what im talking about by looking at the pic.


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For the tail body i wont explain much cause if yall have read the "Extended tail" threads out there yall know how the shape is made. Any whoo seance the tail ends up smooth silicone im not using plastic scales mostly because i dont know what JMB FX Studios used for their plastic scales maby u might know Mark, im going with the PearlieMae scale method without the powermesh because im sure that the scales will stick to the silicone body, i think that the individual scale method will give the tail more flexibility cause like three layers of plastic scales is bound to make the tail body more rigid.

For the rest of my design is just basic extended tail knowledge.(2mm neoprene base, securing belts, maybe a zipper in the dorsal but may not be needed depending on the foot pocket and accessibility.)

[MarkF]

I'd read that for Darrel Hannah's tail they didn't have any closures, instead they glued her in. She couldn't eat or drink anything during her day, they'd thought she wouldn't go to the bathroom as much.

[Merman Andrew]

According to the H2o making of videos JMB FX used cut up plastic drink bottles for their scales (at least that's what was used for the H2o tails)

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[Marinus Mortimer]

Yeah thats true they said the same thing about the Mako Mermaid Tails i guess the only thing they changed was the propulsion mechanism. But i would not use plastic for my scales i rather use individual silicone scales like the PearlieMae way!

[MarkF]

When you watch them gluing each scale, it appears to be silicone. The scales seem to be convex, so maybe the bottle story is an analogy.
I think they are vacuformed polycarbonate.
Think how may bottles.

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[Marinus Mortimer]

It makes seance that they could be vacumformed lexan i never thought of that.

[Merman Andrew]

Its vacumformed plastic. Confirmed here: https://youtu.be/KaVh5cRwWtg

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[Lili]

Oh wow these are some cool concepts, I watched it and they basically said they hand cut each scale out of plastic bottles, they must've had a ton of people working on that because making scales like that alone takes weeks.

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[Rett]

Sounds amazing Mark! Have you thought of trying to actually make just the extension first though to see how it would fit in a tail before you figure out how to add extra moving fins?