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Bore size of snorkels

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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Just visiting...
Aug 26, 2001
This is what I know or have heard about snorkels....

Larger bore sizes tend to have more volume(as long as lengths are similar) and would seem to contain more residual CO2 when at the end of an exhale. Upon inhaling, that volume of CO2 would be brought back into your lungs before fresh "air" comes in.

Some people say that there's an "optimum" bore size that minimizes this residual CO2 and makes for a good breath of "clean air". My thoughts are that if it's easier to inhale/exhale due to the increased bore dia., it seems I'd facilitate my ability to suck down air to my mouth and in turn would reduce the effort to do so. Maybe the residual impurities aren't enough to make up for the easier breathing?

Other thoughts?

sometimes I like to try to look through my snorkel like a parascope...anybody ever try to put mirrors in theirs to accomplish this?:eek:
Dead Space

Some basic things about respiratory phsyiology:
Dead space is the volume from the mouth to the area where gas exchange takes place in the lungs (alveoli). The area in between (oropharynx, larynx, trachea, bronchi) is called "dead space" as it does not participate in gas exchange. Retained CO2 in this area makes respiration less efficient.
A snorkel increases the dead space by the volume it contains. It makes sense that a wider snorkel has more dead space. However, aerodynamics come into play. A thinner tube will have more resistance to airflow (think of breathing through a straw). So, there must be an optimal bore where resistance is fairly low and dead space minimized. In addition, any kink, narrowing of the snorkel must be avoided. Short length is a must (just as long as we know how to clear). The best snorkels I have used (that fit the criteria above) are the Beuchat Mundial and Picasso Nodo. Hope this helps.
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Thats what Ive been ranting about! That is one informative, kick-ass, old school answer! Thanks Frogman, didnt know anybody knew so much about snorkels;)
I never really thought about my snorkel much until I lost mine and borrowed a spare from Andrsn. His was far superior to mine so needless to say, he now needs a new spare. It was the last piece of equipment I ever thought about but it is worth experimenting with.
IMO, AQA makes the best one on Earth. :D There's a picture of it in Sven's latest Caption Contest.

Thanks for the reply guys. Feel free to put some more topics in the "Networking" thread. :) It's sticky, so it'll always stay at the top.

The dead space area makes sense because it is going to contain the last of a person’s exhale, and be sucked back in on the next inhale. Good insight Frogman. I guess that is why on my final exhale I try to close my throat and mouth cavities to eliminate as much of this space as possible.

As far as resistance goes, I think it’s all in what you like. I remember Eric F. saying that he took all of his record attempt dives breathing through an Impulse 2, which is a dry snorkel, because the lower resistance of plain tube, wasn’t worth the risk of getting any water on his breath up.

The water I dive is usually choppy, not like when Anderson visits Rig (Anderson, you should sell good luck dolls of yourself!) and I like the security of knowing I won’t be getting any water. I use an Ocean Master dry snorkel. I don’t have a long breath up hunting and when I see a fish I might only have time for one full breath, and I hate having to change plans because a waved topped my snorkel. I make a choice to have a bit more CO2 and air resistance.

Then again, the water drag of a dry snorkel top, can be, well a real drag. Eric, gets to leave his snorkel on the top. So in that respect, I am jealous of plain snorkel divers. Another problem, I have discovered is once I got used to a dry snorkel, I can’t dive without it.

Good thread,

P.S. Frogman, are you going to the Performance Clinic? I thought Scott said you were at one time, but I haven't heard anything since.
I, too, am still on the quest for the perfect snorkel.

I used to have a Picasso model that I really loved, but ended up biting the mouth tabs off during an underwater hockey game.:head

I have tried The Nodolo and didn't likje it at all because the bore was too small.

I have an Impulse II, but it is too big to drag around while freediving. So I have different snorkles that I end up using for different purposes.

I played around with the idea of tying-off my Impulse II to the float if I am just playing around on a line. This is something that I rarely do, but it worked out really well because I could get such a nice full breath in while on the surface.

I bought an H20 snorkel, with a purge valve on it, for underwater hockey. It has a nice large bore and the valve really helps when you hit the surface breath-less and have to swim to the other end of the pool and catch the guy that just stold your puck.:head

For spearing, and most of my freediving, I use a Sporasub Samauri. It is very low profile and works great for spearing. It has a smaller bore than my other snorkels so I use it for swimming laps as well. I have read that swimming laps with a smaller bore snorkel will help too improve your lung volume. I don't know if this is true or not, but when I switch to my larger bore snorkel for hockey I really notice a difference.

I have tried my wife's Oceanmaster "dry" snorkel. All I can say about this one is that you BETTER spit your snorkel when you dive down our your going to get you tounge sucked right out of your mouth.:waterwork

A buddy of mine went to DEMA and opened up as an OMER dealer. He just bought a complete set-up and I am planning on showing him the ropes tomorrow. He got in a couple of the OMER Zoom snorkels and I hope to get to try one of them out.

I also have a whole drawer full of other snorkels that I don't care for too much. They just sit there until someone needs to borrow one for a trip.

Oceanmaster - you BETTER spit your snorkel when you dive down our your going to get you tounge sucked right out of your mouth

Several people said the same thing last year when we had a snorkel thread. Funny thing is, I have never experienced this with this snorkel. It's my second one too, and I have 4 other brands as well. Oh well, I guess its good it works for me. Is your wife’s the ridged or flexible one? Mine the ridged.

The Impulse II I bought isn’t dry at all. I think its defected, but I never bothered with sending it back.
Which model of the AQA do you have? I tried a couple but found myself liking the Impulse II because it is pretty dry in choppy conditions.

When I was at the Pacific Cup, I saw a number of divers using snorkles. The snorkles had a rigid neck, fair sized bore and were not attached to the mask, simply held in their mouth. When they dove, they would hold the snorkle in one of their hands. Upon surfacing and taking a breath or two, they would stick the snorkle back in their mouth. I only observed this on the warmup lines. They wouldn't let me near the comp line :D .

When Lisa G. and her friends were visting here from England I noticed that she had the same snorkel as me, Sporasub Samauri, but would never strap it onto her mask. She would just leave it tucked under her mask strap (Ted does this all the time) unless she was going deep, and then she would stick it in her belt.

When I freedive with my scooter I take mine out and stick it in my belt. THe movement on the scooter is so fast that I feel like it's going tocome right out of its holder. Plus, it flops around so much while I'm diving that it really bugs me.

Don, my wife has the rigid tube one and it always happens to me if I go below 20' and forget to spit out the mouth piece.

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I use a cheap U.S. Divers with the useless-plastic-thingy-at-the-top-thats-supposed-to-keep-out-water-but-just-restricts-air removed. It's basically a very simple, rigid snorkel with a small purge valve. With the top gone, the tube is relatively short and the diameter is relatively narrow, but not so narrow as to restrict the flow. Seems to work as well as the Samurai that I lost -- maybe better, and I've learned to love the purge valve. And it's cheap -- like me.

If I really want a comfortable dive, I usually try to breathe up on my back w/o the snorkel.

When under water the snorkel is always in my belt. This occasionally makes for some comical photographs.

Piccaso nodo is a top snorkel very soft and flexible though not to sure about the bore size suits me fine though.

Re: Snorkels

Originally posted by Rolando
Any made by Cressi-Sub that would fit the aforementioned criteria?

I think cressi-sub America, has a relatively large bore with short tube structure. Has anybody tried it?
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I have Tubair by Becuchat.

I'd just want to add that fhe soft snorkel is the best for spearfishing, it also should be curved to follow the shape of your head. For ambush and hunt in holes it's important cause it often touches the rocks. If it's hard plastic it vibrates too much when you hunt in the surf. It's very nasty when you don't take the snorkel out of your mouth and you stick your head in some hole and the snorkel starts scratching onto the walls. It may hrt your mouth.
And two thumbs up for the short snorkels!
I have never used the really soft silicone models like the one on the photo (Tubair Activa). I'd love to hear some comments on them.


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I've just read an article that, ideal snorkel has to be about 25mm in diameter and 25-30cm in lenght...
Hi all, good thread

I always went for maximum bore and figured the few cc of extra dead space wasn't enough to worry about. I use an ancient Farallon with a mouth piece that molds to my teeth, a considerable advantage after an hour or two. The bore on this one appears to be a little larger than what is sold in the dive shops around here. It is a little difficult to clear out the last few drops of water.
snorkels snorkels everywhere

This has to be one of my biggest obsessions. I'm sick I tell ya.
I've spent many hours browsing the ass-end of the internet looking for my perfect snorkel. Conclusion: Does not exist. Why? Because [like a bride on her wedding day] my expectations are impossible. The six on the left collect dust. The last one is my 'frankensnorkel'. Recombination of 3 or 4 different parts. I have gotten to the point where I will buy a snorkel simply for the mouthpiece....or the purge....or the bendable silicon piece....or the top tube. S-I-C-K.

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what about the dead space between the ears?

If you can't find an out of production and no longer available, Farallon, and I've got a new $100 bill sittin' here for you if you do, the AQA knock off is about as close as I've found to doing the job right.
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