Info on all-rubber Cressi Fin Needed

[a shark tooth]

Can anyone tell me anything about these fins?

They are in near perfect condition, and they are complete rubber...

The sole of the fin says the following:

Cressi-sub
Rondine
Pro-Rubber

Blade
Hardness 85-90 Sh
U.T.S. 140 kg/cm
Elastic Efficiency 25%
Specific Weight 1.15

38-39
Size 5-6

Made in Italy
Genova-Quinto

Anyone?

 

[DRW]

Here's an image of a pair of size 8-9 Cressi Pro-Rubber fins that fetched $30 in an online auction ending on 3 March 2010:

Further images can be found on the auction site at
NEW CRESSI-SUB PRO-RUBBER SZ 8-9 DIVE FINS/SNORKL : Everything Else at GunBroker.com

Cressi Pro-Rubber fins are listed as candidates for UWH in the Underwater Hockey Directory at
The Underwater Hockey Directory

I have no documentary evidence to back up my hypothesis, but I'd venture a guess that Cressi Pro-Rubber fins date from around the 1980s or 1990s. Cressi followed Mares' lead in the 1970s/1980s by moving from all-rubber into composite plastic fin technology. Pro-Rubber fins were probably intended for diehards like myself who were reluctant to embrace the plastic revolution, preferring heavier fins and wishing to stick to what we knew best. In the same era, Cressi brought out X-Rubber fins, which came with plainer blades than the Pro-Rubber fins in the auction picture. I own a pair of X-Rubber fins and I can confirm that they too have very stiff blades. I remember reading a message on a vintage diving forum where somebody complained about the extreme rigidity of the X-Rubber's foot pockets.

The information on the sole of the Pro-Rubbers is the most extraordinarily detailed I have ever encountered in any fins. It's particularly unusual to find a metric of blade stiffness, which is measured by a "durometer" in "shores". "U.T.S." may stand for "ultimate tensile strength", the maximum engineering stress level reached in a tension test. "Elastic efficiency" may have something to do with the amount of elongation remaining after a stretch test plus a rest period, a test applied to rubber fins in Malaysian Standard MS974: "Specification for Rubber Swimming Fins". "Specific Weight" is expressed in grammes per square centimetre. The foot sizing 38-39 is European, the sizing 5-6 is either American or British.

Hope this is of some interest and use. You do indeed have a little bit of fin history in your possession, Like Technisub's with their Alas, they represent Cressi's final run with all-rubber full-foot fin technology. They'll be no more than 30 years old and if they're pristine, they'll have "New Old Stock" status.

 

[a shark tooth]

Thanks DRW

Appears to me that you know everything about rubber fins

I was seeing if anyone was interested in taking them off my hands! Guess I'll hold onto them haha...

a shark tooth