List and features of jet fin clones

[Sbiriguda]

In the beginning, there were the Scubapro jet fins...it was 1965 an age ago
Since then plenty of jet fin clones have been put on the market, especially after the jet fin patent has expired and other companies had the chance to imitate the same design
I would like to try to list the most important jet fin type fins and to understand if they really differ one from the another. Which ones are best? What are the differences? Are Scubapro jet fins still the best or someone improved the original design?
Thanks

 

[David Wilson]

Don't forget that Scubapro Jet Fins weren't the first jet fins. That honour went to the company headed by Georges Beuchat in the French port of Marseilles. He invented and patented the original Beuchat Jetfins during the early 1960s and continued manufacturing them for the European market, including a full-foot version, long after Scubapro started making its own Jet Fins States-side.

If you're interested in Jetfin clones, the following Beuchat publicity image may be worth your attention:

"Mondialement copiée" is French for "copied worldwide". Can you identify all the copies? The flags provide clues to the countries of manufacture.

 

[Sbiriguda]

Didn't know that...Interesting
So I guess Scubapro started manufacturing them under Beuchat licence

 

[David Wilson]

Didn't know that...Interesting
So I guess Scubapro started manufacturing them under Beuchat licence

Yes, indeed. There's a thread here that covers the bases:
Different Jet Fin Makers - What's the difference? [Archive] - Scuba Forum - Scuba Diving Forums and Discussion Board
But I'm pretty sure that if you do a search of the Scubaboard forum you'll find plenty of more recent discussions of the topic of (Beuchat) Jetfins and (Scubapro) Jet Fins along with their many imitators, considering the continued popularity of these traditional vented fins here.

 

[Popgun Pete]

The Spanish fin is the Nemrod "Venturi" fin, my dive buddy had a pair. The venturi or tunnel ran the length of the blade and it had blocky flow stabilizers on the outer blade surface that were molded lugs. Their thrust was due to their stiffness and they were relatively flat rather than angled in the blade and were quite rugged in their construction. I think the jet action assistance was zero and exiting at the blade tip did nothing for the performance. US Divers made a “Spoiler” fin with two long tunnels and like the “Venturi” they had tip exits, but bar the fins squeaking as the upper and lower blades rubbed on each other the performance came from their enormous side ribs and they were quite hard to push. I gave them to my buddy to try, but he did not like them either.

 

[David Wilson]

Right, Pete has got us started by correctly naming the Nemrod Venturi fin, which is pictured above as the Power model with its Nemrod Venturi "twin", the Nemrod Venturi Delfin, on the left.

Here's that Beuchat publicity image again, this time with the eight Jetfin clones numbered for easier identification:

We now know, thanks to Pete, that No. 2 is the Nemrod Venturi Power fin, made in Spain. The unnumbered one at the top is the original Beuchat Jetfin in one of its full-foot versions. What about the others?

 

[happy-diver]

jetfin, ridiculously small "foot" pocket heavy fin for fifty years
espoused by small footed tech divers worldwide, like vendetta because they must


cerich fin, neutral fin for feet with whichever footwear you choose

 

[Popgun Pete]

Number 6 is the US DIvers "Rocket" fin which had no blade overlap, just three vents. They were pretty tough fins and US Divers sold plenty of them. At one time they were molded in red, white and blue rubber as a patriotic option. Something for sharks to nibble! The "Spoiler" was originally envisaged as a three full length tunnel "Rocket" fin, but ended up as a twin tunnel with a different shape to the blade being a more squared off fin at the blade tip.

Tabata joined in with their own open heel fin, but to be different had two vents going one way and the center vent the other with no real rhyme or reason for doing so. Thus the outer vents were like the "Jetfin" and the central vent was open in the back and exited out the front of the blade. Hydrodynamics was a guessing game and the workings of the fins were delegated to the marketing men to make something up.

 

[Popgun Pete]

True jetfins have venturi action tunnels to send water at higher velocity over the rear of the fin blade on the downstroke so that turbulence at the blade tip is eliminated with water flowing over both surfaces of the blade. On the up stroke to stop suction effects in the tunnels a line of relief holes is positioned across the face of the front blade. Copies either don't have these ports or put them in the wrong place because the copyists don't have a clue as to why they are there. If the tunnels are short they are not needed and at one time Beuchat left them out, but soon put them back in with the long blade fins. The "Super Jetfin" had three vents as a signature element, but no tunnels and just had mighty long blades and was a Jetfin in name only. They arrived to take on the new plastic fins such as the Mares "Power Plana".

 

[Popgun Pete]

I remember Healthways decided to go one better and produced a fin with six vents, none were much more than windows to send water to the back of the blade on the downstroke. This lessened kick effort and the thrust, so to compensate these fins usually had big side ribs and strakes to stiffen them up and were not Jetfins as such. There was an Asian fin with a series of vents running down the blade in a plastic fin, but these seemed to vanish without trace as drag would have gone up with all those window edges and nothing much to show for it in terms of thrust.