Jet Fin vs Rocket Fin

[David Wilson]

I'd also like to thank Sam for his message #11 about the history of fins. I'd like to add a little more historical information:

Jet Fins were originally designed by the French diving equipment company Beuchat, headquartered in the French Mediterranean port of Marseilles. Beuchat's original "Jetfin" version was a full-foot, closed-heel design, with an additional heel strap for a secure fitting:

Throughout the sixties, in Europe where they were invented, full-foot fins were considered top of the line when it came to fins and priced accordingly much higher than open-heels. I've read somewhere that the largest-sized Beuchat Jetfins were manufactured as open-heels because making them full-foots would have resulted in them being prohibitively expensive.

Moving on to the modern era, a YouTube video appears to show Scubapro Jet Fins being assembled in an unnamed factory. Online research suggests that the factory in question belongs to Pacific Molding Inc of Corona, California (pacificmolding.com). You can watch the video for yourself at

YouTube - How is made - Scuba Dive Rubber Fins

The pale-blue fins in the initial sequence appear to be Oceanways Aquapros. There is evidence that UDT Duck Feet are also manufactured in the Pacific Molding facility now that their moulds have been repatriated from Mexico to the USA by Greg Deets:

AllAboutSurf.com - An Interactive Surf Magazine

Hope this additional information is of interest to somebody.

 

[Nemrod]

Early pre lightening bolt Jets:

Lightening bolt Jets:

Fins:

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[John C. Ratliff]

I will have to agree with Duckbill that there is a big difference between the original Jet Fin and the Lightning Jet Fin. They have a difference in formulation and stiffness, as well as overall size. The Lightning Jet Fin is far superior to the original Jet Fin. The Rocket Fin was competing with the original Jet Fin when it came out, and so should be judged by that.

I would also agree with Dr. Sam Miller that the original Duck Feet fins by Swimaster were superior to the Jet Fins. Here's a very old US Navy photo of diver using the Duckfeet fins:

Note the cupping, or "scooping" action of the fin. This is along the lines of my Scoop Fins, which I developed in the late 1960s and still use today. The Mares Quattro Plus is close, and I hear they have a new fin, the Wave, which incorporates most of the scoop attributes. Here is a photo I took in 1970 in Alexander Springs State Park of the scoop concept. Note that this concept works both on the upstroke and the downstroke:

But back to the Lightning Jet Fin; I have done extensive testing, and the Lightning Jet Fin is great on the downstroke, but stalls badly on the upstroke. This is a direct result of the overlapping blades and the design which makes a very large "dead space" on the fin where the overlap occurs on the upstroke. Here is a comparison photo of my latest version of the Scoop Fin with the Lightning Jet Fin:

I have a pair of Rocket Fins in the garage, and will get them out in a few minutes, after supper (priorities, you know).

SeaRat

 

[dumpsterDiver]

I started with the Dacor Turbo fins. Unvented, stiff and probably performed somewhere between the Rocket and the jet fin. I've moved to full foot freedive fins after using jet fins for around 10-15 yrs. I've broken at least 5-6 jet fins over the years, but I can be very tough on gear.

I'm quite confident that the long freedive fins are better, especially my rather expensive fiberlass composite blade fins, but I still have the jets around if I needed to dive with a very heavy boot.

The full foot, freedive fins are harder to put on and take off, are trouble on some ladders, a total pain on a small boat, probably more fragile than a jet fin, but once you get in the water, they work noticably better than jet fins for me. They are also much less likely to get tagled in line, compared to a jet fin.

 

[Nemrod]

UDT fins:

The Dacor fins were more like the Rockets, stiff as a board.

Jet Fins:

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[John C. Ratliff]

I just looked to two pair of Dacor Turbo; I have the Turbo II and the Turbo III, and neither of them are very good. They are actually stiffer at this age than are my USD Rocket fins. The Rockets were pretty good, but probably not quite where the original Jet Fins were performance-wise. I also have two pair of the original Duck Feet fins, and they are very, very good fins. I used to wear them upside down, which you could not do with the AMF Voit Duckfeet, which were the successor when Swimaster (Spearfisherman) was bought by AMF Voit. Swimaster apparently destroyed the original dies for the Duck Feet, so that they could not be reproduced. But Nemrod is correct about the Rocket being a fairly stiff fin. While not as stiff as the Dacor Turbo, it nevertheless was too stiff for very good performance.

Dumpsterdiver, I just brought my monofin back out of the storage shed, and will put it back into the water. When you start talking about the long bifins with plastic or fiberglass blades, you are talking about a whole different level of fin from the vented fins, and a different propulsive concept. These fins, and the monofin, are built on the "S" curve concept, rather than either the displacement or scoop concept. I still like the scoop concept better, but the long bifins are comparable in my opinion. By the way, for those who don't know, the reason that these full-foot fins or closed heel strap fins (like the Duck Feet or USD Aqualung, which is also a very good fin) doesn't hook on the lines is that they don't have a buckle. That's all--just smooth rubber.

SeaRat

 

[John C. Ratliff]

For those interested, here's the drawings of the Murdock patent upon which the concept of the scoop fin is based--and the reason I don't have a patent on the concept.

SeaRat

 

[duckbill]

Jetfins are all I dive anymore. I also have a pair of the X-Large "Superjets". The Supers are fine for cruising around, but I found them a bit much for my scrawny legs when kicking against river currents. The regular Jetfins are perfect. I did crack a pair at the side spine, so I had to get out of the habit of standing on the tips or using them to dig in against the current.

 

[Texfrazer]

One of the more interesting things I did when I first discovered the Jet (or lightning jet, to be more precise), was to borrow one of a buddies and used it with one of my standard fins. It was really funny, I swam in circles!

From there on out, I have used jets.

Personal, head-to-head tests - always the best determining factor, when you can do it.

 

[Nemrod]

I was never sold on the scoop idea. Jet Fins do not scoop. I think the only manufacturer that gets into the scooping concept is Mares and a few other off brands like this:

I don't want to scoop ice-cream, I want to propel forward or backward or sideways which Jets do very well. That said, I just got some Mares Avanti X3 on closeout for nothing, they have the typical Mares scoop design, similar to the Quatrro but with a shorter blade. I want them for a travel fin. My wife likes hers, we shall see.

I think some fin designs, like the split thing, work very well for one type of kick and one type of diving. I kind of put scooping fin designs there, a good paddle design like the Jet with it's ribbed flat blade is an all around do everything well fin. Which is why Jets are best!

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