It had been handcrafted in PVC, at the end of the 50s, by someone from a group of marine biologists who worked in the Baltic, operators for whom its two-tube structure had a precise meaning. It had a certain diffusion in the Postdam diving clubs, in East Germany, until at the beginning of the following decade the Veb Degufa company of Berlin began to build it, calling it "Bonito".
The double tube snorkel
The success was very limited and the strange contraption was mostly the subject of jokes and ridicule for its shape, until it disappeared from circulation. It has returned to the forefront in recent times, now rare and intriguing for its operation, much sought after by collectors.
Its trapezoid shape reveals the cyclical flow of the air breathed, regulated by a butterfly valve that directs the pure inhaled air towards one tube and the exhaled air, rich in CO2, towards the other. The usual floating ball closes the air inlet the moment it hits the water.
The two-tube snorkel and the air cycle circuit diagram
A construction dictated therefore by purely technical reasons, with which it was avoided to inhale that small quantity of "dirty" air that inevitably remains at the end of each exhalation in the usual cyclic circuit tubes. A solution aimed at providing maximum well-being to those who for work spent a lot of time in the water to study the organisms of the nearby seabed.
__________