# Design suggestions for underwater frisbee: fluid dynamicysts wanted **URL:** \ **Category:** Factual Questions\ **Created:** [June 13, 2002, 6:22am UTC](https://boards.straightdope.com/t/design-suggestions-for-underwater-frisbee-fluid-dynamicysts-wanted/113803 "2002-06-13T06:22:57Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![choosybeggar](https://avatars.discourse-cdn.com/v4/letter/c/8c91f0/32.png) [@choosybeggar](https://boards.straightdope.com/u/choosybeggar)\ **Post date:** [June 13, 2002, 6:22am UTC](https://boards.straightdope.com/t/design-suggestions-for-underwater-frisbee-fluid-dynamicysts-wanted/113803/1 "2002-06-13T06:22:57Z")
Flinging discs is by far my favorite activity. The magic of their flight through the air is enchanting. Let us not forget that there are fluids besides air. Water comes to mind as a readily available, inexpensive, recreational fluid. Conventional frisbees cannot “fly” underwater. Too much viscous drag is my hand waving explanation. My question is what modifications to the air frisbee design might produce a practical underwater frisbee? ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [June 13, 2002, 6:31am UTC](https://boards.straightdope.com/t/design-suggestions-for-underwater-frisbee-fluid-dynamicysts-wanted/113803/2 "2002-06-13T06:31:53Z")
Drag is your problem, alright. I don’t see how you’re going to get around that. It takes energy to move that water, and it’s got to come from somewhere. Better put a propeller and a motor on your Frisbee. ---
**Author:** ![ski](https://avatars.discourse-cdn.com/v4/letter/s/bbe5ce/32.png) [@ski](https://boards.straightdope.com/u/ski)\ **Post date:** [June 13, 2002, 7:58am UTC](https://boards.straightdope.com/t/design-suggestions-for-underwater-frisbee-fluid-dynamicysts-wanted/113803/3 "2002-06-13T07:58:15Z")
Drag is the problem, but the only way to reduce that (and still have a “frisbee”) would be to make the disc thinner, or something like an Aerobie. However, you still has to move your hand through the water to throw it, and that’s a lot of drag right there. You just can’t move your hand very fast, therefore you can’t throw the frisbee very fast/far. I’d think that you’d only get a maximum of a foot or two out of a frisbee thrown underwater. So keep your games close together. ---
**Author:** ![femtosecond](https://avatars.discourse-cdn.com/v4/letter/f/f08c70/32.png) [@femtosecond](https://boards.straightdope.com/u/femtosecond)\ **Post date:** [June 13, 2002, 9:48am UTC](https://boards.straightdope.com/t/design-suggestions-for-underwater-frisbee-fluid-dynamicysts-wanted/113803/4 "2002-06-13T09:48:23Z")
No, drag isn’t the main problem. I’ve seen people on TV playing underwater-handball with a ball filled with saltwater. They were able to throw it a few meters and it sure looked like a nice game. But you’ll more or less lose the gyroscopic stabilization. With the density of water, the slightest angle of attack is able to make a disc tumbling. Your stabilization has to come from the shape. There might be a compromise shape between high inertia, low area, and stability. I’m afraid it will look like a penguin. ---
**Author:** ![femtosecond](https://avatars.discourse-cdn.com/v4/letter/f/f08c70/32.png) [@femtosecond](https://boards.straightdope.com/u/femtosecond)\ **Post date:** [June 13, 2002, 10:58am UTC](https://boards.straightdope.com/t/design-suggestions-for-underwater-frisbee-fluid-dynamicysts-wanted/113803/5 "2002-06-13T10:58:46Z")
And, people, always remember to avoid googling before posting. Here’s the official aquadisc website: [http://www.aquatoy.net/v5/products.html](http://www.aquatoy.net/v5/products.html) :smack: ---
**Author:** ![ski](https://avatars.discourse-cdn.com/v4/letter/s/bbe5ce/32.png) [@ski](https://boards.straightdope.com/u/ski)\ **Post date:** [June 13, 2002, 12:13pm UTC](https://boards.straightdope.com/t/design-suggestions-for-underwater-frisbee-fluid-dynamicysts-wanted/113803/6 "2002-06-13T12:13:20Z")
Well, what do you know? I had no idea that would be possible. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [June 13, 2002, 1:50pm UTC](https://boards.straightdope.com/t/design-suggestions-for-underwater-frisbee-fluid-dynamicysts-wanted/113803/7 "2002-06-13T13:50:47Z")
They make “torpedoes” that you can throw back and forth underwater. They’re shaped like a skinny blimp with a pointy nose, and are heavy (the same density as water). You can throw one from one side of a back-yard pool to the other. I sure wish they had those when I was a kid! I’ve had great fun with them, and I’m 41 years old. ---
**Author:** ![JeffB](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jeffb/32/188_2.png) [@JeffB](https://boards.straightdope.com/u/JeffB)\ **Post date:** [June 13, 2002, 2:54pm UTC](https://boards.straightdope.com/t/design-suggestions-for-underwater-frisbee-fluid-dynamicysts-wanted/113803/8 "2002-06-13T14:54:28Z")
> [@](#): > > \*Originally posted by choosybeggar \* > Let us not forget that there are fluids besides air. The air must really be thick where you live. 😃 ---
**Author:** ![femtosecond](https://avatars.discourse-cdn.com/v4/letter/f/f08c70/32.png) [@femtosecond](https://boards.straightdope.com/u/femtosecond)\ **Post date:** [June 13, 2002, 3:29pm UTC](https://boards.straightdope.com/t/design-suggestions-for-underwater-frisbee-fluid-dynamicysts-wanted/113803/9 "2002-06-13T15:29:43Z")
toypedo: [http://www.poolproductsdirect.com/toysandaccessories/toypedo.html](http://www.poolproductsdirect.com/toysandaccessories/toypedo.html) Now that’s much more like the penguin shape I was thinking of. > [@](#): > > Main Entry: fluid > Function: noun > Date: 1661 > : a substance (as a liquid or gas) tending to flow or conform to the outline of its container > > © 2002 by Merriam-Webster, Incorporated “Being a fluid” or just “being fluid” means “being able to flow” (same root). It can be applied to gases as well as to liquids.