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'Underwater bicycle' propels swimmers forward at superhuman speed

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Re: 'Underwater bicycle' propels swimmers forward at superhuman speed

#201

Post by EnigmaFlare »

Chrupiter wrote: post #196
user20180120 wrote: post #194

Would this device be even better if it has the newer efficient propeller design called MX-1 Sharrow Propeller ? https://www.boatus.com/expert-advice/expert-advice-archive/2... At the 2020 Miami International Boat Show, Philadelphia-based Sharrow Marine introduced the culmination of a seven-year research and development project called the MX-1 Sharrow Propeller. Unlike every prop that's come before it, rather than bla…

Would it be a good idea to try on wind turbines?

Utility scale wind turbines are already about 50% efficient which is close to the theoretical limit of 59% (Betz limit). The loopy blades would be more expensive to manufacture and transport so there's a trade-off and it's not obvious that efficiency would win.

Re: 'Underwater bicycle' propels swimmers forward at superhuman speed

#203

Post by bambax »

> French company Seabike

They have a .fr domain and a showroom in Cannes, France but the company is headquarted in Italy:

  PARITET SRL, Via Giovanni da Cermenate 3, 22063 Cantù (CO) Italy
Also, the French version of the website is riddled with enormous errors, like "For traveling light" translated as "Pour voyager lumière", which does not make any sense and isn't even grammatically correct (the proper translation would be "Pour voyager léger").

The whole thing does not inspire a lot of confidence. Is the product real?

Re: 'Underwater bicycle' propels swimmers forward at superhuman speed

#205

Post by bbarn »

arturkesik wrote: post #164
uncertainrhymes wrote: post #35

I swim because I enjoy it, not because I'm trying to get somewhere fast. This seems awkward and I bet you have to use your arms just to counterbalance the twist you'd get on each 'stroke' of the leg. So even though I think it's goofy, I bet I'd like whoever came up with this. Someone who put a ton of effort into building something they thought would be interesting despite a thousand people telling them it's goofy. Go…

I come from family of scuba divers, and the scuba divers are a perfect market for this I think - pretty rich, pretty lazy and have to cover a lot of distance underwater

My wife and I rented the double subnado things last time we were out of town diving. Seems that fits the pretty rich and lazy market much better.

Re: 'Underwater bicycle' propels swimmers forward at superhuman speed

#206

Post by IncreasePosts »

tetris11 wrote: post #200
dyauspitr wrote: post #186

Earlier quoted context omitted.

For very, very short distances I can run faster than most people can cycle.

For mere fractions of a second, I can outwalk a jet.

Well that's easy, jets can't walk.

Re: 'Underwater bicycle' propels swimmers forward at superhuman speed

#207

Post by sandworm101 »

dyauspitr wrote: post #188
sandworm101 wrote: post #42

Earlier quoted context omitted.

Not really. Most serious lap swimmers can do a kilometer every 20 minutes sustainably, akin to a marathon runner's pace (Sprint pace would be 100m/minute, with 50m/minute being what you would see in the fast lane of most recreational pools). So 3.6 kph isn't all that different, maybe a little faster than average but I assume they were also using a better-than-average bicycle person when doing the test. There real adv…

A mid tier marathon runner can do a mile every 20 mins, not a kilometer. It’s a significant difference.

I meant the effort required for the pace, not the literal speed. For a skilled swimmer, 20min per km can be maintained for a few hours, like a runner maintains marathon pace for a few hours.

Re: 'Underwater bicycle' propels swimmers forward at superhuman speed

#208

Post by sandworm101 »

lupusreal wrote: post #154
sandworm101 wrote: post #143

Earlier quoted context omitted.

It has been a while since I was a competitive swimmer (AAA+) but imho five minutes is a very good time for 500m. That would be faster than 95% of master swimmers at such distances, and well into the 0.01% of humans overall.

Ah shit your right, I had in mind 500 (yard) Free. 500 meters in under five is very good, but still attainable by the upper tier of highschool swimmers I think. I could reliably do 500 yards in under five and was a "B relay" tier on my team.

A couple things. 500m is not actually an event. The event is 400 meters, which is roughly 500 yards. And a yard pool will only be 25 yards, not 50. So yard times are "short course" and not really valid for serious competition. A 25-meter/yard pool has fewer turns making them faster, much faster in breaststroke. And a 500-yard in a 250meter pool will include one extra lap, one extra turn, than a 400m in a 25-meter pool. Short-course/yard times all seem faster than they really should be, regardless of distance conversions.

Re: 'Underwater bicycle' propels swimmers forward at superhuman speed

#209

Post by dzhiurgis »

user20180120 wrote: post #194

Would this device be even better if it has the newer efficient propeller design called MX-1 Sharrow Propeller ? https://www.boatus.com/expert-advice/expert-advice-archive/2... At the 2020 Miami International Boat Show, Philadelphia-based Sharrow Marine introduced the culmination of a seven-year research and development project called the MX-1 Sharrow Propeller. Unlike every prop that's come before it, rather than bla…

keep an eye on https://www.youtube.com/@rctestflight - they are doing 3d printed prop benchmark/competition and he already tested design you mentioned

Re: 'Underwater bicycle' propels swimmers forward at superhuman speed

#210

Post by nurple »

user20180120 wrote: post #194

Would this device be even better if it has the newer efficient propeller design called MX-1 Sharrow Propeller ? https://www.boatus.com/expert-advice/expert-advice-archive/2... At the 2020 Miami International Boat Show, Philadelphia-based Sharrow Marine introduced the culmination of a seven-year research and development project called the MX-1 Sharrow Propeller. Unlike every prop that's come before it, rather than bla…

I think for water, what you really want is to _breed_ cavitation, but in a way where the jets created by bubble collapse are arranged to face opposite your desired direction of motion. Kind of like Astrophage.
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