Question Truefins

[Angelo Farina]

When dealing for efficiency (distance traveled over oxygen consumption) one should look at what freediving recordmen employ.
Of course they aim for maximum efficiency...
And here is the answer by Umberto Pellizzari (but other recordmen use the very same type of fins):

https://deepbluesub.com/prodotto/c4-pinne-by-umberto-pelizzari/

 

[Truefin]

I think changing the plastic buckles to perhaps the aluminium ones used by Tusa a few years ago would be better as it increases robustness. I've seen many plastic buckle break after taking a knock, plastic buckles kind of negate the strength of the spring straps. For me plastic buckles would be a deal breaker.

Good luck, I do hope you find success.

Thanks for the comment. We do not manufacture fin straps. We include the Trident R558 Medium stainless steel straps with large Truefins, and they have worked well. There is a R559 configured as you described, and we may have to look into that option and take a survey to see what most divers prefer. The quick release of the r558 has some advantages I suppose, although it is a spring so maybe it's easier to just stretch the spring when needed. This image is out of the Trident 2023 catalog.

 

[Truefin]

When dealing for efficiency (distance traveled over oxygen consumption) one should look at what freediving recordmen employ.
Of course they aim for maximum efficiency...
And here is the answer by Umberto Pellizzari (but other recordmen use the very same type of fins):

https://deepbluesub.com/prodotto/c4-pinne-by-umberto-pelizzari/

Truefin is overall about 24 inches long. Our testing has been limited to scuba fins, and none of them measured more than 27.5 inches long. It does bring to mind if there has been any objective testing of long freediving fins, but we are not currently set up to test such fins. We will be machine testing in open still water with a boat just to get better data with less turbulence, so we will have an opportunity to determine the efficiency of long fins (36" - 48" long).

 

[Angelo Farina]

Truefin is overall about 24 inches long. Our testing has been limited to scuba fins, and none of them measured more than 27.5 inches long. It does bring to mind if there has been any objective testing of long freediving fins, but we are not currently set up to test such fins. We will be machine testing in open still water with a boat just to get better data with less turbulence, so we will have an opportunity to determine the efficiency of long fins (36" - 48" long).

Can you provide more info on your fin testing machine?
I had seen just one water tunnel for fin testing, developed by Luigi Ferraro and Gianni Beltrami at Technisub in the eighties. You can see it here: http://www.luigiferraro.it/files/images/26 Beltrani.preview.jpg

 

[Truefin]

Can you provide more info on your fin testing machine?
I had seen just one water tunnel for fin testing, developed by Luigi Ferraro and Gianni Beltrami at Technisub in the eighties. You can see it here: http://www.luigiferraro.it/files/images/26 Beltrani.preview.jpg

Angelo,

There are images and descriptions at:

Testing — Truefin

www.truefintechnical.com

The instrumentation is on that web page, but pasted below... One thing we found out is that a one horsepower motor works, but sometimes at higher flutter kicking speeds with Truefin the motor would trip off. We will be upgrading the motor to 1.5hp. Also, we had quite a bit of turbulence at higher speeds, and that is why the data was so noisy.

• Motor – Marathon – microMAX AC Inverter-Duty Motor, 1 hp
• Controller – Automation Direct – GS2 Series AC Drive
• Torque sensor – FUTEK - Rotary Torque Sensor – TRD/TRH/TRS 600/605/705 Series
• Adapter – FUTEK – Model USB520 – External USB Kit (mV/V, amplified and encoder input)
• Load cell – FUTEK Model LLB350 – Miniature Load Button
• Software – SENSIT by FUTEK – Version 2.2.4000.0

Regards,
Joe

 

[Angelo Farina]

Truefin is overall about 24 inches long. Our testing has been limited to scuba fins, and none of them measured more than 27.5 inches long.

Here the fins I use for scuba diving, also in caves:

As you can see they are 80 cm long (31.6 inches) including the foot pocket.
Many scuba divers use these kind of fins in places where there are strong currents, such as in Sicily and at Maldives (that is where I did dive the most).

 

[Angelo Farina]

Angelo,

There are images and descriptions at:

Testing — Truefin

www.truefintechnical.com

The instrumentation is on that web page, but pasted below... One thing we found out is that a one horsepower motor works, but sometimes at higher flutter kicking speeds with Truefin the motor would trip off. We will be upgrading the motor to 1.5hp. Also, we had quite a bit of turbulence at higher speeds, and that is why the data was so noisy.

• Motor – Marathon – microMAX AC Inverter-Duty Motor, 1 hp
• Controller – Automation Direct – GS2 Series AC Drive
• Torque sensor – FUTEK - Rotary Torque Sensor – TRD/TRH/TRS 600/605/705 Series
• Adapter – FUTEK – Model USB520 – External USB Kit (mV/V, amplified and encoder input)
• Load cell – FUTEK Model LLB350 – Miniature Load Button
• Software – SENSIT by FUTEK – Version 2.2.4000.0

Regards,
Joe

Thanks, this really very interesting.
Most fin manufacturers do not use objective measurements for optimizing their fins. You are one of the few serious manufacturers!

 

[Truefin]

Thanks, this really very interesting.
Most fin manufacturers do not use objective measurements for optimizing their fins. You are one of the few serious manufacturers!

Thanks.

I've been involved in developing a number of products to the market, and have to say this is the first time I have actually had some fun doing it. I would have killed this project if it was only mediocre. Having said that, fins are a very personal accessory, and Truefin is not for everybody.

 

[Angelo Farina]

Thanks.

I've been involved in developing a number of products to the market, and have to say this is the first time I have actually had some fun doing it. I would have killed this project if it was only mediocre. Having said that, fins are a very personal accessory, and Truefin is not for everybody.

I like the idea of being able to personalise your fins exchanging those coloured "vertebres", so you can adapt their stiffness for different users and different drag due to different equipment.
In the past this was done exchanging the blades.
But your approach is interesting, as your system behaves as not linear system: the blades flex easily for small thrust, when the thrust increases the vertebres become more stiff, avoiding that the fin collapses into excessive flexure.
Traditional high efficiency fins (used by deep freedivers) are optimized for just a very specific amount of thrust.
Your design allows for good efficiency over a range of thrusts...

 

[Truefin]

I like the idea of being able to personalise your fins exchanging those coloured "vertebres", so you can adapt their stiffness for different users and different drag due to different equipment.
In the past this was done exchanging the blades.
But your approach is interesting, as your system behaves as not linear system: the blades flex easily for small thrust, when the thrust increases the vertebres become more stiff, avoiding that the fin collapses into excessive flexure.
Traditional high efficiency fins (used by deep freedivers) are optimized for just a very specific amount of thrust.
Your design allows for good efficiency over a range of thrusts...

Angelo,

We've communicated before on this board. Do you think these fins will fit you? Men's US size 9-13 depending on the bootie. If they might fit we'll send you a free pair with the full kit, Blue, Yellow, and Green spines, ,,and you can post publicly here what you honestly think. No rush, but I would be interested in your thoughts,,, and many divers here would likely be interested. You certainly have relevant experience with fins, but no big deal if you would rather not. Fins are of course very controversial, so you may want to avoid this. Send me a direct message with a shipping address if interested.