If you think that strength is the main factor to consider in snorkel keepers, you are dangerously mistaken.
The single most important feature in a snorkel keeper is its drag resistance. I will address the kevlar keeper below, but in order to properly discuss the drag issue, it is important to isolate the variables involved.
Drag equals Dynamic Pressure * Surface Area * Coefficient of Drag or:
D=1/2 pV^2 * S * CvD
where
p = density of water (I used freshwater in my calculations to be conservative)
V = Velocity (the "safe" ascent rate of 30'/min)
S = Surface Area (the two keepers I've compared are nominally different)
CvD = Coefficient of Drag (in this instance, it's related to the model and material - both test keepers were silicone which has a significantly lower coefficient of drag than kevlar)
Using the two snorkel keepers shown below (again, both are silicone), one can see that their main difference is shape.
Test Subject 1
http://www.momentoffame.com/snapshots/MomentOfFame/l19692.jpg
Although one might think that the larger size of Test Subject 2 would be a detriment, considering the increased surface area, When the model is folded in half (as it would be worn) and run through a water tunnel simulator, you can clearly see that the trailing protrusion actually reduces drag when compared to Test Subject 1 (see figures 3 and 4).
So looking at the facts shown above, one can clearly see that if you choose you use a snorkel keeper like Test Subject 2, you could probably get by with a 13CF pony. However, if you suffer from the increased drag of a keeper like Test Subject 1, you had better go with at least a 19CF pony. And Kevlar Keepers? If you foolishly decide to use one of them for their "strength," you had better just go ahead and strap on another 80
Final Design:
Designed using Pro/Engineer 2001 solid modeling tool, this snorkel keeper is assumed to be made out of medical grade silicone rubber impregnated with Teflon and dipped in a light silicone-based oil (can't tell you details, looking for a patent), see link below. We ultimately selected Test subject Design 1, because those extra tabs cost us 1/10 of a penny on a lot of 100, which means a $22.50 hit in a 1 year production run.
That's interesting Inlet..... I've been contemplating these issues with my snorkel keeper for a few years now. I have never considered the importance of the drag factor.
I'd like to hear more input on the Kevlar idea. That would truely be an innovative product on the Scuba scene. More info please.
Any other input from other members on this??
jonnythan
May 22nd, 2003, 10:03 PM
I'll take 100.
:)
ElectricZombie
May 22nd, 2003, 10:08 PM
LOL :thumb:
I've eliminated the keeper all together by super glueing the snorkel to the side of my head.
Doof
May 22nd, 2003, 10:52 PM
I believe there's a flaw in your water tunnel simulation.
The snorkel keeper is travelling in the wrong direction. Assuming water flow in the direction indicated in your diagram, the snorkel keeper should be rotated 90 degrees clockwise.
Perhaps you need to take your product line back to the drawing board?
Pez de Diablo
May 22nd, 2003, 11:14 PM
Now I need to find that snorkel, since you have found the solution to my problem.
:D
Cave Diver
May 23rd, 2003, 12:31 AM
My snorkel keeper produces ZERO drag in the water. It's called my gear bag, and it holds my snorkel firmly in place during every dive... :)
mddolson
May 23rd, 2003, 11:08 AM
Inletsurf, you have way too much time on your hands.
Nice ProE model by the way.
However silcone snorkel keepers are existing and available (without your logo) for about $1.40 US ($2 Can).
By the way the additional drag (without the analysis) doesn't take a PHD in hydro dynamics. Compared to the snorkel it's The (Square root of 2)/8 x 2/3rds of 4/5ths of FA.
Mike D
:blfish:
Big-t-2538
May 23rd, 2003, 11:19 AM
Cave Diver once bubbled...
My snorkel keeper produces ZERO drag in the water. It's called my gear bag, and it holds my snorkel firmly in place during every dive... :)
I have something similar...it is commonly referred to as the trunk of my car....
SueMermaid
May 23rd, 2003, 11:19 AM
I just staple the thing to my temple. Those little keepers rip my hair out.
pcscuba
May 23rd, 2003, 11:26 AM
I think some people have too much time on their hands. How much does the drag of a snorkel keeper really affect anything? I guess I just don't get it.
Boogie711
May 23rd, 2003, 11:39 AM
How much does the drag of a snorkel keeper really affect anything? I guess I just don't get it.
Dude - just how much diving do you do?
I'll check around to see if I can find any NRC or CSIRO studies on drag coefficient vs. air consumption. By some estimates, a properly tuned snorkel keeper, fresh from annual service, can reduce air consumption by as much as 40-44%!
A lot of people use snorkel keepers that haven't been serviced in years. Any LDS should tell you that a snorkel keeper service, while not mandatory, is an investment that more than pays for itself over the space of a few dives. It's a real wonder that most LDS's don't push this service more often.
I just got two snorkel-keepers back from my LDS - the bill for the servicing was $33, but I think it's more than worth the investment. The only pain is how long the turnaround time is - my LDS says a proper service job can take upwards of a week.
kayakgonediving
May 23rd, 2003, 01:49 PM
After losing several snokels in the surf, I secure my snokel in my fouth point of contact. Takes some geting used to, but I always know where to find it. :upset:
richhermes
May 23rd, 2003, 01:52 PM
Boogie711 once bubbled...
I just got two snorkel-keepers back from my LDS - the bill for the servicing was $33, but I think it's more than worth the investment. The only pain is how long the turnaround time is - my LDS says a proper service job can take upwards of a week.
The issue is not the labor charges, it's the parts bill that kicks your a$$. I have NEVER gotten a SK annual service without at least a $25 parts charge!:wacko:
I have also retrofitted a couple snorkel keepers using Inlet's research and they make great beer bong holders!
Crispy
May 23rd, 2003, 05:14 PM
ElectricZombie once bubbled...
LOL :thumb:
I've eliminated the keeper all together by super glueing the snorkel to the side of my head.
Try some Medical grade staples, if you dip them in Tetanis vaccine first, it will save on the cost of a shot later:D
-Crispy
Jeffe
May 23rd, 2003, 08:43 PM
At temperatures near or below 35* F., the Coefficient of friction is amplified due to the linear stress applied to the polymers.
Due to this increased friction, will the Improved snorkel keeper be able to perform in an adequate manner during extended Ice Dives ?:doctor:
bwerb
May 23rd, 2003, 09:56 PM
kayakgonediving once bubbled...
After losing several snokels in the surf, I secure my snokel in my fouth point of contact. Takes some geting used to, but I always know where to find it. :upset:
So what your saying is that you have your snorkel stowed where if some one told you to blow it out your a** you would indeed be able to accomplish just that.
I just use a little bendy-straw from Dairy Queen myself...doesn't take up too much room at all.
SM Diver
May 24th, 2003, 10:59 AM
Brilliant, Inlet!
For me, it's a confidence thing. If I'm down deep, I can handle the fact that the majority of my dives are solo, the sharks are friggen out of control this year, and I've got dying fish clipped to a d-ring on my BC. However, an improperly designed or maintained snorkel keeper will just flat get in my head everytime and cause untoward anxiety (thus affecting my SAC, as well).
Diving injuries secondary to poorly designed snorkel keepers have not been given the attention they deserve. I have inside information that the engineering department at Stanford University has received a grant from PADI to properly examine this issue, and resolve it once and for all.
kayakgonediving
May 29th, 2003, 03:35 PM
bwerb once bubbled...
So what your saying is that you have your snorkel stowed where if some one told you to blow it out your a** you would indeed be able to accomplish just that.
I just use a little bendy-straw from Dairy Queen myself...doesn't take up too much room at all.
I'm told that's how most start, and sooner or later, the snorkel ends up back there.
Many people tell me to blow it out my a**. I wonder if that is what they mean???
Pony bottles cause signifigantly more drag, has anyone addressed that?
drbill
May 29th, 2003, 07:10 PM
ultimate snorkel keeper. I simply put it in my dive bag before I head under. Seriously that's what I'm tempted to do. It serves a function for about 2% of my dive and then is nothing but trouble as I try to videotape in crannies and crevices.
Dr. Bill
get-wrecked
June 2nd, 2003, 06:21 AM
I found a great use for a snorkle. If you cut a hole in the backside of your wet suit and insert the snorkle in your A** it makes a great Addition to the halcyon P-valve! And as a bonus it's right wear you can reach it if needed, providing of course you rinse the mouth piece.
pcscuba
June 2nd, 2003, 08:07 AM
that's pretty nasty get wrecked but funny though:)
kayakgonediving
June 2nd, 2003, 01:38 PM
Excellent idea by Get Wrecked. Where do you secure your pony bottle?
f94gator
June 4th, 2003, 08:56 PM
I am shocked and chagrined at the utter void of attention paid to the snorkel keeper and its relation to nitrox depth limits.
Think increased drag doesn't affect your absorption of nitrogen, eh?
Think a fouled keeper at 130' won't contribute to O2 tox, eh?
THINK AGAIN!!!!
richhermes
June 4th, 2003, 09:14 PM
I have found thru extensive research that snorkel keepers make an excellent substitute to a powerhead for self defense.
I have found that if you get the highly elastic keepers you can flick or shoot them at the shark like a rubberband. Nothing, I mean absolutely NOTHING will spook a shark like a snorkel keeper upside the gills!!
Save the .223 ammo for the manatee steaks, buy a handful of keepers for those shark dives!!=-)
inletsurf
June 4th, 2003, 11:02 PM
Hmmmm.... you might be on to something Rich. Like the plastic six-pack holders that snagged storks and pelicans, a snorkel keeper can be a diver's last defense mechanism against predators like sharks, or even aggressive turtles. I'll have to study that one a little closer.
As far as the other replies, I sense a bit of sarcasm going on here. One guy even replied that he keeps his snorkel up his anus. I find this the least bit funny. I spent 3 weeks of my life researching older designs, from Navy emergency duct tape designs to techie neon green 80's dive stuff to the black silicone of today. I have submitted a patent on my new design and I won't be patronized by you all. Hell you guys are so behind the times you don't even know what Im talking about. Most of you still wear neon colors and believe that buddy diving crap I bet.
But, being a genius and expert techie diver that I am, listening to the snorkel up the anus reply gave me a new use for my snorkel keeper--- the techie diver's extra-leg constrictor ring. A necessity for plunging into caves that can get kinda hairy at times.
scubajoe4-2-0
June 4th, 2003, 11:24 PM
i suggest that some of the members of this board try doing this with their snorkel. it may releave most of the stress that is caused by your snorkel. what u need is first your trusty snorkel. next you need some aluminium foil, along with a good screen, something that pokes good holes, a good lighter, and some fat bud. i know im leaving out some items, but for the full report, with a well drawn out scientific graphical representation of what your snorkel should look like for one to achieve the upmost potential out of your snorkel....
click here (http://www.baltimorestoners.50megs.com/bowl.html)
now just sit back and enjoy your new creation.
JCKCSYCMD
June 5th, 2003, 12:19 AM
The obvious lack of knowledge on this topic is distressing!
Snorkels have a very important usage in ice dives. I am dissappointed that the respondents have not been aware of this!!
I am convinced of this seeing so many photos of ice divers with snorkels still strapped on. I can speculate that when they see an ice fishing lure and line, they can sneek up to the ice fishing hole, insert the snorkel into up into the hole and point towards the unsuspecting ice fisherman. Take a good hard breath, spit out their 2nd stage and blast the unsupecting ice fisherman right between the eyes. Water cannons taken to a new chilling level.
Caution: Do NOT attempt this under an ice fishing shanty where there are spear fisherman waiting for northern pike, muskies, or sturgen!
Rick Murchison
June 5th, 2003, 07:57 AM
Doesn't this discussion belong in the "DIR" forum rather than the "DIY" forum??????
Rick
