Vents on Jet Fins?

[Bob Evans]

Have not had any experience with scuba pro fins have used the fazers but my personal experience is apex rk3 they have not changed a thing in years for a reason.

Best move it to do nothing ....till the other side moves. X-Ray Mag - International Dive Magazine Conversation with Bob Evans - Force Fin

 

[Bob Evans]

I bet @Bob Evans could explain…Engineers - Force Fin

Well I might write a book on vents but found these winglets really made a change,

 

[tursiops]

Wow.
61 posts ago Post #1 asked how vents work on fins. Post #2 said I'll bet Bob Evans can explain. in Post #17 on Oct 18 Bob Evans says he has to go swimming first, will explain when he returns. on Oct 30, in post #51, he explains that a folded piece of paper is stiffer than a non-folded piece of paper. In post #57 on Nov 25 he explains how the split in split fins works. He talks more about this in post #58 on Nov 26. In post #61 he offers a business principle of waiting until your competitor does something. Finally, today, in post #62 he finally returns to the original subject of vents...and talks about winglets.
It is pretty clear that he has no idea of how vents work, just that:

vents do not function in the matter most thing [sic] they do.

The best response so far is from David Wilson in post #15, who provides the original patent info.

 

[Bob Evans]

Wow.
61 posts ago Post #1 asked how vents work on fins. Post #2 said I'll bet Bob Evans can explain. in Post #17 on Oct 18 Bob Evans says he has to go swimming first, will explain when he returns. on Oct 30, in post #51, he explains that a folded piece of paper is stiffer than a non-folded piece of paper. In post #57 on Nov 25 he explains how the split in split fins works. He talks more about this in post #58 on Nov 26. In post #61 he offers a business principle of waiting until your competitor does something. Finally, today, in post #62 he finally returns to the original subject of vents...and talks about winglets.
It is pretty clear that he has no idea of how vents work, just that:

The best response so far is from David Wilson in post #15, who provides the original patent info.

 

[Bob Evans]

Ditto Wow! Thank you for spending your time organizing flow of communication with my posts. Now, let's step into the water and visualize the flow through vents and around wing tips.https://forcefin.com/engineers/

 

[Island23]

What exactly are the vents supposed to do on Scubapro Jet fins?
I was looking at them and wonder if they are actually counter productive?
It looks to me like on the downward stroke of a standard from the hip flutter kick that water will gush through those vents but what would be the benefit?
It seems like that’s wasted thrust.
I know those Scubapro version fins are from a 1965 design but what sort of science were those fins based on? Or was there any?
Was it a marketing gimmick?
People use them now doing all sorts of frog kicks, helicopter turns, backing up, etc. and love them, but back then nobody was doing that stuff (that I’ve heard about anyway), it was all standard flutter kicking.
I can confirm that they do suck for regular flutter fin kicking, but they do work well for everything else.

Jets are open water blue water ocean going fins, it's how the Navy dives, instead of frog kicking. Navy dives timed & its a full sprint. The divers are strong & can flutter the kicks 10,000 times, without even needing a frog kick. Navy trains using flutter kicks for distance, that's the Jet fin, followed, by others like the Rocket II & RK3 HD, which have been modernized to exceed their previous versions. Put it this way, out of 1,000 kicks, 1,000 are flutters, if you are competing & for your life but even for training, 90% will be flutters. Navy doesn't have time to look pretty & slow down to do perfect frog kicks for efficiency & pretty helicopter turns. You just swim from A-B & sprint it, CO2 build-up doesn't matter, with young divers.

The Jet lives off of being stiffer, which is hard for new divers to use, while the Rockets & RKs remedied problems of comfort, portability, tech & tactical uses. The Jet doesn't have as many vents, channels & wings because it hasn't changed, it's sold, as a classic fin now. Yes, it needs changed & accepted a bungee already, with maybe less stiffness.

It doesn't have the long term design, doesn't stow & a bungee costs you extra - has its own problems overpriced. You'll loose the fins on a mission & can't even airborne. It's, like others said, yes, it is marketing now days & popular, with old generations & as such, sold as a classic - like a Harley motorcycle.

It does not have the best vents. If speed is, what matters to you, there are lots of Asian fins from Taiwan & China, that are stiffer, faster & modernized, at 1/4-1/2 cost. Jets are made in Taiwan now & any differences from the original makes it better, not worse. People don't like that notion because they used to be Made In USA fins, hard for them to accept, that anything else could be better.

How or why the vents are like that, I'm not telling you, you have to be smarter than a professional aeronautics engineer teaching NASA classes for the military - not just a backyard engineer.
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Oh & about fins, I was diving before Dive Rite even existed or even sold their company, in Florida & with the Navy, in those caves. I dove their locations, before they even formed & then in Pensacola, Panama City, Jacksonville & Key West. Their fins aren't the best for caving or blue water. While they were teaching rec, everyone else here was working on the boats, oil rigs & diving Navy. Their fins are too long & stiff for caving, don't know, what it wants to be, so it isn't better at anything. Plus, that's localized to Florida, everyone else in the world dives the deep blue, while they're stuck diving underground collecting rocks, it's a sickness, compared to the open world.

 

[Pressurehead]

Jet fins, I did not like them when I was required to wear them in the Navy [Australia] while under training , I changed to the Mares fins [in black, what else] when I was allowed [rank helped], this was a long time ago, Mares Concordes? And Planas , Concordes, I think that was the name.
Planas I had for years.
Also changed to a TUSA mask.
I have gone a little off topic.

 

[tursiops]

How or why the vents are like that, I'm not telling you,

I assume this is because you do not know?

Oh & about fins, I was diving before Dive Rite even existed or even sold their company, in Florida & with the Navy, in those caves. I dove their locations, before they even formed & then in Pensacola, Panama City, Jacksonville & Key West. Their fins aren't the best for caving or blue water. While they were teaching rec, everyone else here was working on the boats, oil rigs & diving Navy. Their fins are too long & stiff for caving, don't know, what it wants to be, so it isn't better at anything. Plus, that's localized to Florida, everyone else in the world dives the deep blue, while they're stuck diving underground collecting rocks, it's a sickness, compared to the open world.

I assume this is sarcasm....because it doesn't make a lot of sense otherwise.

 

[lexvil]

I assume this is because you do not know?

I assume this is sarcasm....because it doesn't make a lot of sense otherwise.

Much of it was lost to me but I don’t speak fluent Florida man

 

[tursiops]

fluent Florida man

oxymoron