Rookie Snorkel question incoming.

[Jeggie]

Hello.
Just spent a nice weekend in 2-5ft waters experiencing my first taste of Snorkelling and absolutely loved it.
As an Engineering designer, I need to sate my curiosity about Snorkel design with this one question:
I could have done with another 4" on the length of my snorkel as looking underneath myself and the odd wave occasionally souped up the end.
It appears that Snorkel length is set in stone and here's the rub - I totally understand the tidal air concept and how dangerous it would be to rebreathe an increasing proportion of CO2 as a result of a longer Snorkel, BUT... in this wonderful age of plastic and silicon valves, why does this not exist...
** A twin-tube Snorkel with an in-tube (normal diameter but a few inches longer) and an out-tube (could be smaller) both tubes regulated by a valved mouthpiece? **

Now I get the potential drawback of not being able to purge the in-tube of water without some kind of manual or bite-down valve opener but what am I missing? this sounds cool

Thanks in advance for your time.

 

[tommibrem]

Hello.
Just spent a nice weekend in 2-5ft waters experiencing my first taste of Snorkelling and absolutely loved it.
As an Engineering designer, I need to sate my curiosity about Snorkel design with this one question:
I could have done with another 4" on the length of my snorkel as looking underneath myself and the odd wave occasionally souped up the end.
It appears that Snorkel length is set in stone and here's the rub - I totally understand the tidal air concept and how dangerous it would be to rebreathe an increasing proportion of CO2 as a result of a longer Snorkel, BUT... in this wonderful age of plastic and silicon valves, why does this not exist...
** A twin-tube Snorkel with an in-tube (normal diameter but a few inches longer) and an out-tube (could be smaller) both tubes regulated by a valved mouthpiece? **

Now I get the potential drawback of not being able to purge the in-tube of water without some kind of manual or bite-down valve opener but what am I missing? this sounds cool

Thanks in advance for your time.

Hey, not from my own but my son's experience, you'll get quite used to the standard one very quickly. I feel like your idea might add an extra step that ultimately you won't have to use, plus another source of possible malfunction?

 

[Brochman]

Is this what you are looking for? This snorkel self drains with gravity, no purge valve but also no need to blow excess water out of the top of the snorkel. This model was originally made in the late 70's by Scubapro called the Shotgun snorkel but they stopped making this model many years ago and now Gul are manufacturing it under a different name called the Canal-ii snorkel.

Canal II Snorkel – BentFish Armoury

bentfishdesign.com

Or maybe your snorkel was not positioned correctly rather than straight it should be attached to the mask at a angle.

 

[adrian.u]

What sort of snorkel were you using? I've tried a few with some of the purge and valve features, and ended up just going back to the most basic 'no-frills' open tube. I guess others may have different preferences, though, and maybe the ones with such 'extras' that I used were just cheapo versions - so there could be some decent 'full-feature' snorkels out there if you're willing to pay a bit more? YMMV, I guess.

Also, as Brochman said above, position is important...
It's common with inexperienced snorkelers/divers to see the snorkel placed at roughly 45 degrees when putting it on standing upright and looking straight ahead. But this means it ends up tilted at about 45 degrees relative to the water surface when you are looking down into the water. You really want it almost horizontal when putting it on standing upright, so it ends up at ~90 degrees to the water when looking almost straight down into the water - its top is then as high as possible to help reduce water intake.
(I find one way to keep it in about the right place is to insert it between the two back straps of the mask, where the strap splits into two across the back of the head.)

 

[Brochman]

Tips For The Lowly Snorkel • Scuba Diver Life

This slight change in setup will absolutely reduce the amount of water you get in your snorkel, which will benefit any diver, regardless of experience.

scubadiverlife.com

 

[DRW]

National and international standards and rules prescribing breathing tube dimensions have changed over time:

The table above illustrates how these measurements have shifted in response to better understanding of the effects of dead space and breathing resistance on carbon dioxide retention:

• Maximum tube length has almost halved (from 600 to 380 mm).
• Maximum bore (inner diameter) has increased (from 18 to 25 mm).
• Capacity (or inner volume) has partly replaced inner diameter when dimensioning snorkels.
• Different snorkel dimension limits have evolved for different users (first specified as adults/children; then taller/shorter heights; then larger/smaller lung capacities, all of them used as proxies for expected tidal volume, as the ratio of tidal volume to dead space controls the amount of carbon dioxide in the inhaled air of each breath).

In addition to quantitative criteria in their development, snorkels have undergone multiple design modifications claiming to improve performance. After shut-off valves came and went in the mid twentieth century, they later came back into vogue as miniaturised air supply-end devices for modern silicone dry and semi-dry snorkels. The first-generation shut-off valves were declared unreliable because they did not always open and close on cue. The idea of separating air inlets and outlets was also tried in the mid twentieth century and largely found to be impractical. Like many items of diving equipment, the humble breathing tube has been subject to over-engineering with the passage of time, which can lead to equipment failure.

If you are looking for a snorkel meeting your underwater swimming needs, my half-century of snorkelling experience tells me that the simpler this device's operating system is the better. Less to go wrong. If you are looking for an engineering project to design the perfect snorkel, I would urge you to do a proper literature search first, dedicated in particular to the plethora of snorkel patents approved over recent decades. Most of these inventions have never reached the manufacturing stage for lack of funding or because design flaws emerged later. This will save you much time and effort in the short term.