Going back to this video since I've asked our fellow divers and instructors why are they teaching us to do a "half-turn". Some were aware of the older valves but the reason they gave me is that your dive buddy does not accidentally overtighten your valve when doing the aircheck (speaking of bulky and eager guys like Kevin I suppose, haha). The valve turns easily, so your buddy gives it a half-turn to a fully open position and knows your valve is open without looking at it. (Then he or she turns it back a notch). As a newbie diver I am having a blast binge-watching your videos Alec, thank you so much for them! I am so glad they keep coming :)
Welcome to the diving world. There are several more videos on the 1/2 turn back subject so search for them. You have lots to learn and hopefully share with others. Remember to question what does not seen right until the answer makes sense. Have fun diving.
@@AlecPeirceScuba_SeaHunter after watching your videos some of the mysterious habits divers have start to make sense, one of the most recent ones is a habit of wetting the bcd before putting it on the tank 😂 We weren't taught to do that in our basic training but now I see why some guys may do that 👍
Alec has so much wisdom, people should understand that listening to someone that has successfully dived for so many years has so much more value than following any 'modern' instructors with the 'latest tech'.
Thank you Kamil. I'm so old that 'new tech' is just re-done from the old days. It may be stronger, lighter, reliable etc, but not really new to those of us from the stone age of diving.
2018 and to my surprise I was also taught during my padi open water cert to not fully open the tank valve and turning air on with pressure gauge turned away from me. Coming from a technical/mechanical background I found it strange these precautions were needed in the first place... Thanks for pointing out modern scuba equipment is in fact modern :)
Few divers are aware that instructor training does NOT have anything to do with scuba diving training. That is, in a scuba instructor course, the candidates are NOT taught about scuba. It is a business course where one learns about instructor training methods, how to teach and how to organize a scuba instruction business. So, whatever knowledge (or lack of) that the candidate has from his prior scuba training is what he knows. If he learned from his instructor that he should open the valve and then close it a bit, that's what he'll teach. And that's why such outdated scuba concepts are carried forward sometimes for many years. I can guarantee that many scuba instructors today are still teaching that. Things change - people not so much. Take care. Alec
Loved your video. When I got my Equipment Techniques specialty my instructor was a commercial diver with over 12,000 dives. He taught me all things you described in this video. It was nice to here it again and learn even more. Thanks!
Brilliant! I had developed both of those habits (turning valve all the way open, then back a little bit and also holding SPG facing away when turning on air). You are a smart fella Alec!
When I took instruction in 1984, I was told to turn the valve back half a turn from full open. The reason being was as a quick check, if the valve had easy play back and forth, you knew it was open and if not, it was closed. Seems to make sense to me. And, half turn closed from full open is going to have a negligible affect on flow regardless of pressure in tank. P.S. Great videos Alec.
We have a couple of videos that deal with this topic. That '1/2 turn back' is no longer recommended. The downside to the idea that a loose valve shows it is open is that you have no idea if it's completely open or only a little bit. In an earlier video I also featured a device that shows if the valve is open or closed and by how much!!. Take care. Alec
Wow; yes, to both of those items. And I still do them today... So I guess the "proper" answer is to know your equipment, and to what standards its been manufactured to, and then decide what the procedure for the equipment should be. Thanks, as always, for your great explanations.
Hey Alex, love the videos, thanks for all the info. When I recently went through the PADI open water diver course I was given a different explanation; I was told to fully open the valve and turn it back a quarter turn with the idea that when me and my buddy do our pre dive safety check we can easily ensure each other’s tanks were turned on by turning the valve the quarter turn back and to the open stop limit and then turning it back again a quarter turn. The explanation of the half turn reducing the working pressure of your high pressure ports makes sense, however assumingely the quarter turn would have half the effect on the aperture of the valve. Our tanks we used in class did not have the valve indicator you showed in the video, and I like that system a lot however is this an effective solution for easily checking the open/closed status of your tank valve in the absence of an indicator?
You know, whatever works for you and your buddy is the best way B13. I just wanted to show the reason for the 1/4 turn back, which is because of the old valves that would stick open - not as an indicator to your buddy. A valve turned back 1/4 turn is not going to restrict the air flow enough to be a problem. The Valve Position Indicator (Vindicator) is a great idea. I recommend it to every diver. With it, there is no confusion. A non-diver would know what it means!! Failing that, every diver should know automatically which way to turn a valve knob to open it, or close it. It's the same as all water taps and valves - clockwise to close; counterclockwise to open. There are several ways to remember that - you turn it clockwise to close the same as you turn a wood screw to tighten it; some people say lefty-loosey, righty-tighty, meaning you turn left to open, right to close. Simply do it enough and you won't forget. Your buddy should check your air valve on the surface so it's all set to go for the dive - never underwater where you can't communicate nor reach it yourself. Maybe this is a good topic for a video. Alec
At my store we undertook to have them on every training tank. My instructors were very happy. We put them on all of our rental tanks as well. I sold that valve knob for $19.95 - installed!!! Take care. Alec
Hi Alec , you are so right ..after I have watched your video and also do some research by myself .. I always turn my air to maximum until the end and never turn them back half way again. Its so true that ..there are no benefit for me to turn my tank half way back after turn them on. You know ..I just decided to put a little bit investment and buy my own gear.. BCD and also Regulator. I think its important to know my own gear , how is works and take care do services of course by professional for every 6 months or something. BCD , I did picked Aqualung Pro HD which is just arrived..didn't test them yet. Regulator is a bit more complicated.. I spend more time to learn about it and...I think the one that for me , it would be Scubapro MK17 evo, with 2.stage G260... I am very exciting about it and hopefully this would help me to be a better diver ( as now I have only 48 log dives ) . Great Video and Thank you so much for your knowledge sharing with all of us here.
48 dives is a lot! Congratulations. I think you're wise at this point to have your own gear and your choices seem good. Thank you for watching and I hope you've picked up some ideas. Alec
about closing a valve a little bit (open all the way and turn it back half a turn), my instructor told me it is needed for a buddy to check if its opened or closed. about preassure gage, instructor told me to push it to a cylinder, not away from me, when opening a valve (i am from russia by the way).
My 2nd wife was Russian. Beautiful girl. Think about this Alex (nice name!) - if you turn the valve back a bit from full on and your buddy reaches up to check it, it will turn both ways. How does he know if it's almost open or almost closed? You want it fully open so, if you push your purge button and get air and your buddy checks that the valve is snug, you know it's fully open. Quite frankly it doesn't matter what you do so long as you check carefully before jumping in. You sound like you are a careful diver so whatever you do, I'm sure it will be safe. Most of these little "rules" are for the less careful divers, the sloppy ones who cause all the problems. Same with the SPG. So long as it away from your face when the air is turned on, you're good. Take care. Talk again. Alec
Yeah, i didn`t got the thing about leaving valve half turn at first, and i still dont know why they telling students to do it that way, i just makig shure thatvalve didnt opend too hard - that it will be hard to close it after. Thankyou fro your replay :) Alexander (yeah i am actually alexander - alex is just easier to pronounce)
I spotted the turn back a while ago and told my students to face the gauge into their bcd so the disk is away from them and the relief is away from them. tech doesn't always work and I witnessed a gauge blow out all over as short as 3 years ago.
NAUI allows some instructor input into the curriculum so it may well be that some NAUI instructors include this kind of information. It's not universal. Alec
Would there be any chance of a standalone video where you go into the old 'turn back' debate in a bit more detail? When you try to innocently probe the reasoning for doing so, no one has ever able to give me a better answer than 'I was told to do it'. I think a lot of it seems to stem from instructors who, through no fault of their own, do not have a technical understanding of the SCUBA equipment that they instruct on, and simply repeat what they were trained to do. That's one of the reasons why your videos are a real benefit!
You are 100% correct. Instructors are not experts on scuba gear - certainly not today! And we always tend to repeat what we've heard in our own training. So, ideas that are 20, 30 or 50 years old are still being expounded as the truth. This is not to knock current instructors. Divers in general are less aware of the technical details of their scuba gear. The course does not talk about how a regulator works much less how to fix it. Plus regulators today are much more involved (complicated?) than the old ones. The good news is that most of that kind of information is available now on the internet. But I do enjoy sharing my considerable expertise with equipment and will do some more. Thanks for watching. Alec
I think divers of you and my father's generation had that technical background automatically if, for no other reason at least, because you started out by building your own gear in the first place!
Maybe partly. Also, it was the Do-It-Yourself age. People thought nothing of building their own kitchen table, bedroom set, boat, etc. Also, since there were very few dive stores, we had to learn how to take care of our own gear. It was fun and now it must seem to young divers that we're so smart. Nope! Just a different age.
The problem I have found is the internet experts are sometimes wrong. That is why I have been truly ecstatic that I found your channel! Thank you so much Alec! Please keep the knowledge coming. Brian
Alec at the nuclear plant where I worked we were trained not to leave the valve fully open on its backseat but close it a turn or so. We were trained to open the valve fully only if it was leaking at its stem. What’s the difference? Thanks 😊
Well I'm not fluent in nuclear power but I do know scuba gear and the 1/4 turn back started back in the double hose reg days (no longer used) because the "pillar valve" would expand and lock the tank valve if fully opened so a 1/4 turn back prevented the lockup due to old materials and so-so quality. Not so today. I can't answer why your valves are not fully open but the work 'leaking' is not what I want to hear from a nuclear site! Thanks and take care John.
Where i dive in Europe I have never seen a plastic SPG or a pressure relief valve we use metal SPG’s but in case of pressure build up we point it away from my face because the only place where the pressure would escape would be the glass or plastic screen!
If you look on the back of your SPG, with the rubber boot or console removed, you'll see a rubber plug about 1/4" in diameter in the case. That is the pressure relief plug. If the gauge fails (not common, but it happens) that plug comes out like a 22 rifle shot. Anything in the way will suffer, hopefully not an eye! These are required on all SPGs (in fact, all pressure gauges) and apply whether plastic or metal, European or not. Scubapro, GSD, Cressi, etc are all the same. The SPG boot or console is supposed to have a hole in it to allow that relief plug to blow out unobstructed. See if yours has that too. This Tech Tip was directed at those older divers who were told to point the gauge away from their face because the older gauges did NOT have that plug. When these older gauges broke, most often the front glass would burst. With the newer gauges (newer since about 1980!!), pointing it away from your face means the relief plug is facing you! Some divers prefer metal SPGs. Makes them feel safer. That's fine with me. It's not true, but it's fine with me. It's not the case that fails. It's the bourdon tube mechanism inside that fails so metal or plastic case does not make the gauge better. In fact, a metal case, chrome or not will corrode and requires more rinsing. But a metal gauge if the weight is not an issue is fine. The best suggestion to ensure your safety when turning on the air is to hold the SPG behind your back or at the very least look entirely away from the gauge. That way you can't get hurt no matter what happens. Take care Darren. Alec
Lol I was told in 1987 to turn my pressure away... And the instructor demonstrated it and the lens fell off when he turned it towards the ground.. some kids were playing with the study toys ..his name for the non serviceable study guides.. and with out missing a beat said "now if we had 3000 psi that thing would have been stuck in your head the rest of the day!".. lol I still point the pressure gauge say but not with the face or the blowout valve pointed at me or anyone close by. I also was taught to turn the tank on and back off a 1/4 turn... Never really knew why but it always worked. Never knew why it was called a K valve or J valve till now, but when I asked the instructor back in '87 he held up a K valve and said notice how it sort of looks like a K? .. Needless to say, I just went through life thinking some dude named them after his girlfriend or something.
Another reason for turning you valve back was not sited here. The internal components of the modern scuba valve are made of very soft brass. The reason we teach students to turn the valve a quarter turn back its to protect the internal components when someone goes and checks the valve to make sure it is on. If it is all the way open and the diver tries to check it (especially new divers), they can force it past the full open and round out the valve stem. Now the tank is essentially stuck open. So, with the quarter turn back, when a diver checks the air the Handle will move open then stop.
Interesting idea James. Having serviced thousands of tanks valves over my 47 years in the scuba business, I can assure you that the likelihood a diver using just his hands would damage the valve stem is very remote. Yes the parts are mainly brass but all internal parts are closely fitted and have full support around them. Even the 2 forks in the valve are unlikely to break while installed. Modern valves also have a built-in feature that precludes such damage - the knob. Almost all knobs today are molded Cycolac (or some other very tough plastic) with a metal insert that accommodates the thread of the stem. If someone over-tightens the valve, the plastic knob will separate from the threaded metal insert. You may have encountered this. The knob turns but the valve does not open - or close. The knob just spins. Quite common. My suggestion is to teach divers, old and new, to use a tank valve properly. 1. Open all the way 2. Never use more force at either end, open or close, than necessary. That means when opening, stop when you reach the end of the opening action; when closing stop when you feel the restriction of the closing seat. A properly operating tank valve opens and closes with ease. NO force is necessary at either end. If it's stiff, it needs servicing. Keep in mind, and reason for this video, is that the 1/4 turn back was specifically taught as a way to prevent the valve from freezing (read: jamming) open. I taught that for years in the 60's as did all other vintage instructors. No need for that anymore. Thanks for watching James and for your input. Alec
Hi Alec, I agree with you that damaging the valve is highly unlikely and the original reason for turning the valve back is obsolete. However, I do it anyway for a reason that is important if you leave the comfort zone of the recreational diver. Let's say you are diving in a cave/wreck/night/zero viz situation with a dry suit and undergloves and something hits the fan. You need to close the valve NOW. As we all know, thinking underwater is a bit tricky, so I don't want to bet my life on muscle memory of myself or my buddy to definitely turn the knob in the correct direction. If the valve is fully open, it is possible (and I've seen it happen in cave diving courses) that the (blindfolded) diver slips over the knob trying to turn it in the wrong direction. If the 1/4 turn back is there, the knob will turn and stop, thus notifying you instantaneously that you are turning it the wrong way. The 30 seconds or more that it would otherwise take to realize your mistake, can cost your life.
@@tobiashartung856 though you could also make the opposite argument, that a fully turned open valve gives you a more immediate indication on which way to turn the valve to close it.
@@danielmewes That would be the ideal scenario. The point is that you can easily slip over the knob if it is fully open. With thick gloves it is very difficult to tell whether you are turning the knob or slipping along the knob. Thus, you may THINK that you are closing the valve while in reality nothing is happening because you are turning it the wrong way and the valve was fully open to begin with. The 1/4 turn back is much less likely to make you just slip as it will turn either direction. However, if you are turning it the wrong way, the turning will stop pretty much right away. You are very likely to notice that. The 1/4 turn back is therefore a much more reliable indication of which way to turn the valve.
One note not found in the FAQ's is if you do turn the valve back and it's too much at depths as little as 40 feet you can see your tank pressure "thump" (move rapidly) as you breathe and you will find the draw harder. Just simply don't panic and open the valve fully happens regularly in foreign countries with the "turn back" method.
Simply the physical characteristics of the metal. Brass is an alloy of copper and zinc and expands/contracts much faster than most other metals. It causes lots of problems. For fun, look up the origin of the expression "it's so cold that it will freeze the balls off a brass monkey". Take care. Alec
A long time ago I saw a gauge explode and it is not pleasant experience. I know my equipment, but don't know what rubbish someone else is going to turn up that I am giving instruction to, so I always ask them to take precaution to protect themselves and others. Novices are notorious for buying second hand gear when they are first starting out, and this is the reason why I continue with the face and back of the gauge facing away from people.
Good thinking Pug. Just remember that both the face AND the back of an SPG are dangerous. Consider telling them to just cover the gauge with their hand, a towel, dive bag or anything else at hand. Thanks for watching. Alec
Not really. The second stage and the SPG are not directly related. The air for the SPG comes directly from the tank immediately as you turn on the valve. The air for the second travels through the first stage from the tank, is reduced and then along the LP hose to the second stage. Holding the purge down has no affect on the SPG. The safest way to protect yourself from an SPG blowout is to simply put your hand, or a towel, bag, hood, what have you, over the face of the gauge as you turn on the air. In the very unlikely event that the SPG blows, nothing will fly up and hurt you. Thanks for watching Huan. Alec
While incredibly rare, SPGs can still fail. Some modern SPGs don't have pressure relief plugs and some cheap SPGs may have relief plugs which don't work properly. Best practise: Stick your SPG into your BCD while GENTLY tunring on air (turning it on too rapidly puts extra pressure on your system). This protects you (and others) from BOTH a front-face failure and the relief plug popping out. As for the valves, yeah, don't turn them back a quarter-turn, or your friendly helpful DM/buddy might accidentally turn your air off instead of on during the pre-dive trips.
Hi Alec, My scubapro MK2 air gauge is reading more pressure, about 50bar more and I noticed its been flooded. Can I simply air dry the air gauge? the o ring outside the air gauge pop up when I turn on the tank pressure. please help :)
It's very tough to dry out an SPG. You must keep the O-Rings on the swivel pin in good shape. All you can do is remove the SPG head and set it in the sun for a couple of days. That might do it. Blowing air into the open end is not much value since no air will actually penetrate the sealed gauge. It can't be adjusted either so you'll have to live with the inaccurate reading. Normally it will read the same overage at all times so it's working alright, just inaccurate.. Good luck. Alec
Apeks Owners Manual: If a submersible pressure gauge is attached to the first stage, ensure that the gauge is facing away from you. Pressurise the regulator by slowly turning the cylinder valve handwheel anti-clockwise. Continue to turn the valve handwheel anti-clockwise until it is fully open, and then turn it back 1/2 turn.
Either the Apeks gauge does NOT have a blow-out plug on the back (unlikely as most are made by the same company) or they are simply parroting the older diver manuals. Thanks. Alec
So, they still call them "K-valves" simply because one particular catalog just happened to use "K" as the index number on the regulator IPB (illustrated parts breakdown)? That was some cool and interesting trivia!
I'd think, given this fairly compelling information, even the oldest, most seasoned diver or instructor would change their approach! But, people can be hard-headed. I know I'll put this bit of info to use in many activities - welding, using medical O2 for first aid, tire gauges, etc. as I suspect the same design changes apply to all kinds of pressure gauges. I really like the "extra" info you include in your videos to put things into perspective. Seriously some of the best RUclips how-to videos I've seen on any subject.
Not needed. It carried over from the 'stone age' to prevent the internals from seizing up. Does not happen with todays tank valves but causes more problems in verifying on/off.
@@AlecPeirceScuba_SeaHunter Great to know. We still do that with oxygen, acetylene, propane and the like. But, they use the same valves as 40 years ago. Some might even be that old.
I did not deny that you were correct. You gave good and logical reasons - which I always like. However, I can still recall the serious attitude of the instructor on Koh Taoh, Thailand, in 1991, about turning the valve fully on and then back off slightly. He was also very serious about aiming the console away from yourself when you turned on the pressure. I also recall how we had to blow any water out of the dust cap with high tank pressure (you mentioned that was not nice in one of your tips, maybe a different video). My point was most of the things you debunked covered almost all that I recalled so many years later. I thought that was funny. I am enjoying your videos.
I have experienced a plastic pressure gauge explode taking out the front cover. This can happen. I like the final tip of facing the gauge away from you completely and turning your face away. I prefer to use the solid brass gauges. I feel they are much safer.
+John Llorens For several years I've used the Sherwood Wisdom, an air-integrated computer that is hose mounted, not wireless. It's been completely reliable and so easy to use. It's made scuba diving fun again! Re the wireless models, I would have agreed 100% with you even as recently as 2 years ago but the latest models (Oceanic OCi, Sherwood Amphos Air, etc) are as reliable as Bourdon tubes and much more rugged. You can beat the heck out of an integrated circuit but not a Bourdon tube! And the connection seems constant now with no drops. They get better all the time. Soon you'll not be able to get a Bourdon tube gauge. Boy will my vintage collection be valuable then!!
Modern dive computers suffer from the same issue of rupturing the face as in the "50s and 60s." Check out the recall notices. Turning a tank value all the way open is not for the valve seat it is to prevent dethreading the knob by over torquing an already open valve. But, all students should turn the valve completely open as there is more risk of not having an open take than there is of breaking a knob. That "not hard" statement shows you understand this. The clip that holds the know on is not very strong. I am not particularly strong but have broken more than a few knobs BTW. And, in a few thousand dives I have had one dive computer face explode. In front of a student. One her first check out dive.
Question: Is there a valid reason why we don't dive with the cylinder valve at the bottom (Upside down) when mounted to the bcd where the valve is much easier to access than trying to reach up and behind your head? I realise you may require longer hoses, but, why don't we dive that way?
EMS and Fire Fighters use a similar system and their tanks are mounted valve down. There were scuba systems like that. Check out earlier videos of mine to see one.The simple reason we don't use them in scuba is because we want the first stage to be as close as possible to the same level in the water as the second stage and your mouth and lungs. The first stage delivers air at a pressure that varies with depth. Certainly with today's sophisticated regulators, it would be tough to tune a reg if the first stage was 2-3' deeper than the second. The pressure coming from the first would be too high. If you adjusted to compensate for that and then the diver went head down to look into a hole or something, he'd find it hard to breathe. Plus don't forget that we have several hoses coming off the first stage - 1 to the Safe Second, 1 to the BCD, 1 to the SPG and maybe 1 to the dry suit. It could get messy back there with all those hoses going to different places on the diver's body. The current set-up seems to work well. Thanks for watching. Alec
+Michael Ross hi guys, I am not a pro on what is inside the valve but you can break it if you do it to hard. you break the screws that hold the knob and the tank stays open or close depend where you force it. I know cuz I have done it ...
Usually what happens if your turn the knob too hard is that the plastic handle breaks. Then it will turn on the shaft but not turn the valve - the valve is stuck either open or closed. It's an easy fix. Remove the handle and replace it - total cost about $10. The worse problem is that you slowly ruin the sealing seat which will soon require the tank being drained and the valve rebuilt - total cost about $50! DON'T TURN THE VALVE HARD EITHER OPEN OR CLOSED. You can practice this with a tank that has no regulator on it. Open the valve slowly and carefully until air flows. The trun it slowly closed until the air flow stops - STOP TURNING!! That's it. When the air flow stops, the valve is closed. Get used to the feel. Take care. Alec
All adjustments on your regulator mounting and tank valve adjustment should be "hand-tight" only, not wrenched to the point of jamming. The seal in the valve itself is brass-on-brass, and it would take a clearly excessive amount of torque to damage the valve seat. The worst case scenario in this instance is that you'd have to have the valve overhauled (or better still, replaced with a 21st Century-era, stronger valve). You should never use "vintage" or off-brand equipment of any kind. Quality, up-to-date equipment will not be damaged by properly opening the valve all the way, as it always should be. However, the possibility of over-tightening the valve (by a rushed dive master or non-trained deck hand) is yet another reason not to let anyone else touch your gear, except a trusted buddy - ever.
@@AlecPeirceScuba_SeaHunter in a cave when you have to close a valve on a twin system to prevent losing 1 of the cylinders, a broken handle can cost you your life. I also teach the quarter turn back to prevent forcing the handle. What do you lose by turning a half turn back? Nothing. It has pros and no cons, so just do it. I agree the valve handle is cheap, but only if you're on land, underwater when you need to isolate on twins, it could be deadly.
I remember being looked down upon by older divers for not bothering to face my SPG away before opening the tank. I must say, I feel vindicated by this video.
When opening any valve all the way, I always turn it back a quarter turn or so; not to prevent sticking but to keep some bozo who comes along and turns it the same way for some reason and, thinking it stuck; cranks it harder and breaks it!
No one, I repeat, no one touches my tank once it's ready to dive. That's what knives and speargns are for!!! Look for my video on the Vindicator valve. It's in Series 1 and called "Air Check Is So Important" - best $20 you can spend. Take care. Alec
Nope! Heard that it happens but I'm thinking that's rumor. I've seen one get bent but it didn't break. They're pretty tough. It would take a heck of a bang to break off a modern valve. Thanks for watching. Alec
The #1 thing scuba instructors teach that can hurt (kill) you is wearing too much weight. They teach incorrect technique that you should sink feet first after deflating your BC at the surface. You use your fins and swim down, as your suit squeezes you will become negative at depth. They teach to be negative at the surface with your gear on and the BC empty, this is incorrect. You should be slightly positive at the surface, enough that your mouth and nose are out of the water with gear on and BC empty. 40% of dead divers wore too much weight. I wonder who taught them to wear too much?
Being negative at the surface is easier for the instructor - not necessarily best for the diver as you say Kim. Certainly not for new divers. Thanks. Alec
Usually - if you're using an aluminum tank you will likely be a few pounds more buoyant at the end of the dive. That causes it's own problems. Now you will find it had to stop and stay at 15 feet for a safety stop. If, as Kim says, you have correctly weighted yourself so you are barely buoyant at the surface with ALL the air out of your BC, it ought to be OK. If you're too buoyant it will be a frustrating dive, If you're too heavy it may not be safe. Now you understand better why PADI has an entire certification Specialty Course called Peak Performance Buoyancy where you learn and practice good buoyancy.
If you are in the tropics and falling off the end of a boat, there may never be an issue. If you are beach diving in Northern California, you better be able to swim at the surface. The PADI instruction for overweight diving is dangerous and wrong. "some tanks are positive when empty" well, that's a dive that's over. PADI until 2014 taught double drowning=buddy breathing with one second stage. My comment is intended for new divers to get some perspective that PADI is a club comprised of guys who claim to be experts.
I'm not here to defend any agency but, I am an instructor for 8 different agencies so have some perspective. PADI teaches positive buoyancy - floating at eye level with an empty BCD. Also they were the first to introduce the Safe-Second (octopus) as mandatory and the first to drop Buddy Breathing from the curriculum. No 'double drowning=buddy breathing' from PADI! And all this since the 90's, over 20 years. I don't want to argue with you Kim but please check your facts. Don't try to Trump me! Let's hope that PADI knows what they're doing since currently almost 90% of all divers, dive stores and dive charters are PADI oriented. As you say, location and environment can sure change things. What a diver does in Grand Cayman and what he does in California and what he does in Lake Simcoe, Ontario under the ice will be very different. It's pretty much impossible to have an incontrovertible rule for all situations but - it's equally impossible to train all divers for all situations!
Hi Alec, is that positive buoyancy newer in the curriculum? My two PADI courses, not counting refreshers, were in 1991 and 1992, but all the courses and most of the dives I have been on were not really compatible with the positive buoyancy as I recall the dive masters vertically in the water, and everyone just sinking while standing vertically after everyone give the down signal. If I had positive buoyancy, I would need to put my head down and my feet up to descend, wouldn't I? Also, back then, in Australia I had seen some newly certified divers. They weren't just negatively buoyant, they would CRASH to the bottom and then pump a lot of air into the BDC. I guess I am overdue for a refresher by many years, so I will probably learn thin anyway.
Oh yes. Lots of 'stone age' practices still being taught to new divers that don't apply anymore (eg turning the valve 1/4 back from full on). Lots to learn.
+Daniel Mckell You're not wrong in that respect Daniel. I wouldn't suggest that your instructor lied to you. However, I've been teaching scuba since 1969 and a lot of things have changed in all those years. So, what you're instructor learned and thus teaches in his classes, may not be the best information based on newer research or newer scuba gear. Scuba 2000 is a very busy dive facility. We have 43 instructors on staff and one of my jobs is to keep them up-to-date. Many instructors do not teach very often and many have not updated their teaching information or methods despite all of the changes in scuba diving. An example is the teaching of Buddy Breathing. It was a mandatory skill for many years but has not been longer taught to new dive students for several years for good reason. Some instructors continue to teach Buddy Breathing. They either have not updated their course or they don't recognize the importance of removing that outdated skill from their class. I am simply suggesting that some things which were common knowledge and thus commonly taught in scuba classes for a long time are no longer accurate. With that in mind, perhaps you could check out some of these ideas on the internet rather than blindly accepting my ideas or those anyone else. Thanks for your comment. Alec
+Daniel Mckell Even if it's stupid? I mean no offense, but if you're taught something wrong, why continue doing it that way when someone else comes along and gives a very good reason not to do it that way?
Brother-Diver Oscar, I was thinking the very same thing as you!
8 лет назад+1
I've been an instructor for quite some time and I do not disagree with you, but you say this like it is a fact. It is not. For example, a normal SPG used for techincal diving has no over pressure valve on the back, meaning it can face with the back, rather than the front, because that is where the glass or plastic will hurt you. Same goes with all the way on and half a way back. For ME, that is so a student don't start turning the knob on and the knob is att 100, and missing the thread, making it more or less impossible to close without tools. And for the red and green marker... I've been all around the world and made 2000+ dives and have NEVER seen that before, so do not talk about it like it is default config.
Björn Jakobsson So true i use a technical configuration including spg made of metal with no pressure relief valve and even before when I used a normal confirmation I never seen a plastic spg or a pressure relief valve or a green red thing!
Alec for instructors a green red thing really? Isn’t it better that new divers learn by heart they’re buddy check procedures buckles valves releases air final check and they each buddy up with someone and they check each other’s gear in stead of the instructor just looking see if it’s green and that’s it.and what you said about every SPG having a pressure relief valve is simply not true a technician metal SPG has no pressure relief valve on the back the only way for pressure to be relieved is trough the weakest part the glass or plastic screen on the SPG !
Anybody else like me here on this thread think that both Bjorn Jakobsson and Darren Fay are just a couple of argumentative twinkies that just LOVE to spout "contrary?"
Going back to this video since I've asked our fellow divers and instructors why are they teaching us to do a "half-turn".
Some were aware of the older valves but the reason they gave me is that your dive buddy does not accidentally overtighten your valve when doing the aircheck (speaking of bulky and eager guys like Kevin I suppose, haha).
The valve turns easily, so your buddy gives it a half-turn to a fully open position and knows your valve is open without looking at it.
(Then he or she turns it back a notch).
As a newbie diver I am having a blast binge-watching your videos Alec, thank you so much for them!
I am so glad they keep coming :)
Welcome to the diving world. There are several more videos on the 1/2 turn back subject so search for them. You have lots to learn and hopefully share with others. Remember to question what does not seen right until the answer makes sense. Have fun diving.
@@AlecPeirceScuba_SeaHunter after watching your videos some of the mysterious habits divers have start to make sense, one of the most recent ones is a habit of wetting the bcd before putting it on the tank 😂
We weren't taught to do that in our basic training but now I see why some guys may do that 👍
you are so easy to listen to. Thanks for explaining all these things. I'm learning a ton.
Alec has so much wisdom, people should understand that listening to someone that has successfully dived for so many years has so much more value than following any 'modern' instructors with the 'latest tech'.
Thank you Kamil. I'm so old that 'new tech' is just re-done from the old days. It may be stronger, lighter, reliable etc, but not really new to those of us from the stone age of diving.
Oh my god, the gauge points are so true! I love these videos!
2018 and to my surprise I was also taught during my padi open water cert to not fully open the tank valve and turning air on with pressure gauge turned away from me.
Coming from a technical/mechanical background I found it strange these precautions were needed in the first place...
Thanks for pointing out modern scuba equipment is in fact modern :)
Few divers are aware that instructor training does NOT have anything to do with scuba diving training. That is, in a scuba instructor course, the candidates are NOT taught about scuba. It is a business course where one learns about instructor training methods, how to teach and how to organize a scuba instruction business.
So, whatever knowledge (or lack of) that the candidate has from his prior scuba training is what he knows. If he learned from his instructor that he should open the valve and then close it a bit, that's what he'll teach. And that's why such outdated scuba concepts are carried forward sometimes for many years. I can guarantee that many scuba instructors today are still teaching that.
Things change - people not so much.
Take care.
Alec
Loved your video. When I got my Equipment Techniques specialty my instructor was a commercial diver with over 12,000 dives. He taught me all things you described in this video. It was nice to here it again and learn even more. Thanks!
Thanks Barbie.
Glad you enjoyed the review.
Alec
Brilliant! I had developed both of those habits (turning valve all the way open, then back a little bit and also holding SPG facing away when turning on air). You are a smart fella Alec!
When I took instruction in 1984, I was told to turn the valve back half a turn from full open. The reason being was as a quick check, if the valve had easy play back and forth, you knew it was open and if not, it was closed. Seems to make sense to me. And, half turn closed from full open is going to have a negligible affect on flow regardless of pressure in tank. P.S. Great videos Alec.
We have a couple of videos that deal with this topic. That '1/2 turn back' is no longer recommended. The downside to the idea that a loose valve shows it is open is that you have no idea if it's completely open or only a little bit. In an earlier video I also featured a device that shows if the valve is open or closed and by how much!!.
Take care.
Alec
Wow. I've heard all of these things. Thank you for explaining how these practices came about and how tech fixes them.
Glad you picked up something new.
Thanks for watching.
Alec
I'm about to watch all your videos from the start now, I'm learning so much from them! Thanks Alec
Just need to try and remember it all...
So cool! Would love to hear more about your experience of diving in the past :)
Will do Floyd.
A.
Hi Alec, I can relate to a lot of things you said being from old school teaching, thanks for the up-date info.....
Thanks for watching Roy.
Alec
Wow; yes, to both of those items. And I still do them today...
So I guess the "proper" answer is to know your equipment, and to what standards its been manufactured to, and then decide what the procedure for the equipment should be.
Thanks, as always, for your great explanations.
Thanks for watching Michael.
Alec
Very informative! Thank you for your videos sir.
So funny about the K valve. Thanks!
Hey Alex, love the videos, thanks for all the info.
When I recently went through the PADI open water diver course I was given a different explanation; I was told to fully open the valve and turn it back a quarter turn with the idea that when me and my buddy do our pre dive safety check we can easily ensure each other’s tanks were turned on by turning the valve the quarter turn back and to the open stop limit and then turning it back again a quarter turn. The explanation of the half turn reducing the working pressure of your high pressure ports makes sense, however assumingely the quarter turn would have half the effect on the aperture of the valve. Our tanks we used in class did not have the valve indicator you showed in the video, and I like that system a lot however is this an effective solution for easily checking the open/closed status of your tank valve in the absence of an indicator?
You know, whatever works for you and your buddy is the best way B13.
I just wanted to show the reason for the 1/4 turn back, which is because of the old valves that would stick open - not as an indicator to your buddy. A valve turned back 1/4 turn is not going to restrict the air flow enough to be a problem.
The Valve Position Indicator (Vindicator) is a great idea. I recommend it to every diver. With it, there is no confusion. A non-diver would know what it means!!
Failing that, every diver should know automatically which way to turn a valve knob to open it, or close it. It's the same as all water taps and valves - clockwise to close; counterclockwise to open. There are several ways to remember that - you turn it clockwise to close the same as you turn a wood screw to tighten it; some people say lefty-loosey, righty-tighty, meaning you turn left to open, right to close. Simply do it enough and you won't forget.
Your buddy should check your air valve on the surface so it's all set to go for the dive - never underwater where you can't communicate nor reach it yourself.
Maybe this is a good topic for a video.
Alec
That green/red valve indicator is awesome. I wish all tanks came with that.
At my store we undertook to have them on every training tank. My instructors were very happy.
We put them on all of our rental tanks as well.
I sold that valve knob for $19.95 - installed!!!
Take care.
Alec
Thanks for sharing, you are right all the way, that's what my instructor told me !
Love these tips, keep them coming please :)
Hi Alec , you are so right ..after I have watched your video and also do some research by myself .. I always turn my air to maximum until the end and never turn them back half way again. Its so true that ..there are no benefit for me to turn my tank half way back after turn them on. You know ..I just decided to put a little bit investment and buy my own gear.. BCD and also Regulator. I think its important to know my own gear , how is works and take care do services of course by professional for every 6 months or something. BCD , I did picked Aqualung Pro HD which is just arrived..didn't test them yet. Regulator is a bit more complicated.. I spend more time to learn about it and...I think the one that for me , it would be Scubapro MK17 evo, with 2.stage G260... I am very exciting about it and hopefully this would help me to be a better diver ( as now I have only 48 log dives ) . Great Video and Thank you so much for your knowledge sharing with all of us here.
48 dives is a lot! Congratulations.
I think you're wise at this point to have your own gear and your choices seem good.
Thank you for watching and I hope you've picked up some ideas.
Alec
about closing a valve a little bit (open all the way and turn it back half a turn), my instructor told me it is needed for a buddy to check if its opened or closed. about preassure gage, instructor told me to push it to a cylinder, not away from me, when opening a valve (i am from russia by the way).
My 2nd wife was Russian. Beautiful girl.
Think about this Alex (nice name!) - if you turn the valve back a bit from full on and your buddy reaches up to check it, it will turn both ways. How does he know if it's almost open or almost closed? You want it fully open so, if you push your purge button and get air and your buddy checks that the valve is snug, you know it's fully open.
Quite frankly it doesn't matter what you do so long as you check carefully before jumping in. You sound like you are a careful diver so whatever you do, I'm sure it will be safe. Most of these little "rules" are for the less careful divers, the sloppy ones who cause all the problems.
Same with the SPG. So long as it away from your face when the air is turned on, you're good.
Take care. Talk again.
Alec
Yeah, i didn`t got the thing about leaving valve half turn at first, and i still dont know why they telling students to do it that way, i just makig shure thatvalve didnt opend too hard - that it will be hard to close it after. Thankyou fro your replay :)
Alexander (yeah i am actually alexander - alex is just easier to pronounce)
Wish I had those modern valves.
Still using a "J" valve? Then your a stone age diver like me.
I spotted the turn back a while ago and told my students to face the gauge into their bcd so the disk is away from them and the relief is away from them. tech doesn't always work and I witnessed a gauge blow out all over as short as 3 years ago.
Crazy thing is, these things are still taught in the NAUI scuba diver certification course.
NAUI allows some instructor input into the curriculum so it may well be that some NAUI instructors include this kind of information. It's not universal.
Alec
Would there be any chance of a standalone video where you go into the old 'turn back' debate in a bit more detail? When you try to innocently probe the reasoning for doing so, no one has ever able to give me a better answer than 'I was told to do it'. I think a lot of it seems to stem from instructors who, through no fault of their own, do not have a technical understanding of the SCUBA equipment that they instruct on, and simply repeat what they were trained to do. That's one of the reasons why your videos are a real benefit!
You are 100% correct. Instructors are not experts on scuba gear - certainly not today!
And we always tend to repeat what we've heard in our own training.
So, ideas that are 20, 30 or 50 years old are still being expounded as the truth.
This is not to knock current instructors. Divers in general are less aware of the technical details of their scuba gear. The course does not talk about how a regulator works much less how to fix it. Plus regulators today are much more involved (complicated?) than the old ones.
The good news is that most of that kind of information is available now on the internet. But I do enjoy sharing my considerable expertise with equipment and will do some more.
Thanks for watching. Alec
I think divers of you and my father's generation had that technical background automatically if, for no other reason at least, because you started out by building your own gear in the first place!
Maybe partly. Also, it was the Do-It-Yourself age. People thought nothing of building their own kitchen table, bedroom set, boat, etc.
Also, since there were very few dive stores, we had to learn how to take care of our own gear.
It was fun and now it must seem to young divers that we're so smart. Nope! Just a different age.
The problem I have found is the internet experts are sometimes wrong. That is why I have been truly ecstatic that I found your channel! Thank you so much Alec! Please keep the knowledge coming. Brian
Alec Peirce Scuba seriously, Alec, I could not agree more with obar below. Your knowledge Is invaluable, especially as a prospective divemaster.
Alec at the nuclear plant where I worked we were trained not to leave the valve fully open on its backseat but close it a turn or so. We were trained to open the valve fully only if it was leaking at its stem. What’s the difference? Thanks 😊
Well I'm not fluent in nuclear power but I do know scuba gear and the 1/4 turn back started back in the double hose reg days (no longer used) because the "pillar valve" would expand and lock the tank valve if fully opened so a 1/4 turn back prevented the lockup due to old materials and so-so quality. Not so today. I can't answer why your valves are not fully open but the work 'leaking' is not what I want to hear from a nuclear site! Thanks and take care John.
Where i dive in Europe I have never seen a plastic SPG or a pressure relief valve we use metal SPG’s but in case of pressure build up we point it away from my face because the only place where the pressure would escape would be the glass or plastic screen!
If you look on the back of your SPG, with the rubber boot or console removed, you'll see a rubber plug about 1/4" in diameter in the case. That is the pressure relief plug. If the gauge fails (not common, but it happens) that plug comes out like a 22 rifle shot.
Anything in the way will suffer, hopefully not an eye!
These are required on all SPGs (in fact, all pressure gauges) and apply whether plastic or metal, European or not.
Scubapro, GSD, Cressi, etc are all the same.
The SPG boot or console is supposed to have a hole in it to allow that relief plug to blow out unobstructed. See if yours has that too.
This Tech Tip was directed at those older divers who were told to point the gauge away from their face because the older gauges did NOT have that plug. When these older gauges broke, most often the front glass would burst.
With the newer gauges (newer since about 1980!!), pointing it away from your face means the relief plug is facing you!
Some divers prefer metal SPGs. Makes them feel safer. That's fine with me. It's not true, but it's fine with me.
It's not the case that fails. It's the bourdon tube mechanism inside that fails so metal or plastic case does not make the gauge better. In fact, a metal case, chrome or not will corrode and requires more rinsing.
But a metal gauge if the weight is not an issue is fine.
The best suggestion to ensure your safety when turning on the air is to hold the SPG behind your back or at the very least look entirely away from the gauge. That way you can't get hurt no matter what happens.
Take care Darren.
Alec
Lol I was told in 1987 to turn my pressure away... And the instructor demonstrated it and the lens fell off when he turned it towards the ground.. some kids were playing with the study toys ..his name for the non serviceable study guides.. and with out missing a beat said "now if we had 3000 psi that thing would have been stuck in your head the rest of the day!".. lol
I still point the pressure gauge say but not with the face or the blowout valve pointed at me or anyone close by. I also was taught to turn the tank on and back off a 1/4 turn... Never really knew why but it always worked. Never knew why it was called a K valve or J valve till now, but when I asked the instructor back in '87 he held up a K valve and said notice how it sort of looks like a K? ..
Needless to say, I just went through life thinking some dude named them after his girlfriend or something.
A funny story with an instructor who cannot be distracted. Thanks for sharing.
Another reason for turning you valve back was not sited here. The internal components of the modern scuba valve are made of very soft brass. The reason we teach students to turn the valve a quarter turn back its to protect the internal components when someone goes and checks the valve to make sure it is on. If it is all the way open and the diver tries to check it (especially new divers), they can force it past the full open and round out the valve stem. Now the tank is essentially stuck open. So, with the quarter turn back, when a diver checks the air the Handle will move open then stop.
Interesting idea James.
Having serviced thousands of tanks valves over my 47 years in the scuba business, I can assure you that the likelihood a diver using just his hands would damage the valve stem is very remote. Yes the parts are mainly brass but all internal parts are closely fitted and have full support around them. Even the 2 forks in the valve are unlikely to break while installed.
Modern valves also have a built-in feature that precludes such damage - the knob. Almost all knobs today are molded Cycolac (or some other very tough plastic) with a metal insert that accommodates the thread of the stem.
If someone over-tightens the valve, the plastic knob will separate from the threaded metal insert. You may have encountered this. The knob turns but the valve does not open - or close. The knob just spins. Quite common.
My suggestion is to teach divers, old and new, to use a tank valve properly.
1. Open all the way
2. Never use more force at either end, open or close, than necessary. That means when opening, stop when you reach the end of the opening action; when closing stop when you feel the restriction of the closing seat.
A properly operating tank valve opens and closes with ease. NO force is necessary at either end. If it's stiff, it needs servicing.
Keep in mind, and reason for this video, is that the 1/4 turn back was specifically taught as a way to prevent the valve from freezing (read: jamming) open. I taught that for years in the 60's as did all other vintage instructors.
No need for that anymore.
Thanks for watching James and for your input.
Alec
Hi Alec,
I agree with you that damaging the valve is highly unlikely and the original reason for turning the valve back is obsolete. However, I do it anyway for a reason that is important if you leave the comfort zone of the recreational diver.
Let's say you are diving in a cave/wreck/night/zero viz situation with a dry suit and undergloves and something hits the fan. You need to close the valve NOW. As we all know, thinking underwater is a bit tricky, so I don't want to bet my life on muscle memory of myself or my buddy to definitely turn the knob in the correct direction. If the valve is fully open, it is possible (and I've seen it happen in cave diving courses) that the (blindfolded) diver slips over the knob trying to turn it in the wrong direction. If the 1/4 turn back is there, the knob will turn and stop, thus notifying you instantaneously that you are turning it the wrong way. The 30 seconds or more that it would otherwise take to realize your mistake, can cost your life.
Brother=Diver Tobias, excellent point you make sir! I learned something on this technique, & it makes PERFECT sense to me!
@@tobiashartung856 though you could also make the opposite argument, that a fully turned open valve gives you a more immediate indication on which way to turn the valve to close it.
@@danielmewes That would be the ideal scenario. The point is that you can easily slip over the knob if it is fully open. With thick gloves it is very difficult to tell whether you are turning the knob or slipping along the knob. Thus, you may THINK that you are closing the valve while in reality nothing is happening because you are turning it the wrong way and the valve was fully open to begin with.
The 1/4 turn back is much less likely to make you just slip as it will turn either direction. However, if you are turning it the wrong way, the turning will stop pretty much right away. You are very likely to notice that. The 1/4 turn back is therefore a much more reliable indication of which way to turn the valve.
One note not found in the FAQ's is if you do turn the valve back and it's too much at depths as little as 40 feet you can see your tank pressure "thump" (move rapidly) as you breathe and you will find the draw harder. Just simply don't panic and open the valve fully happens regularly in foreign countries with the "turn back" method.
Wow! What timing.
We just did a video about that called "Why Does My Pressure Gauge Go Up & Down When I Breathe?"
Watch for it.
Alec
just out of interest what exactly causes the brass to expand or contract on an old style valve and how did backing it off prevent that from happening?
Simply the physical characteristics of the metal. Brass is an alloy of copper and zinc and expands/contracts much faster than most other metals.
It causes lots of problems. For fun, look up the origin of the expression "it's so cold that it will freeze the balls off a brass monkey".
Take care.
Alec
Thanks, great!
A long time ago I saw a gauge explode and it is not pleasant experience. I know my equipment, but don't know what rubbish someone else is going to turn up that I am giving instruction to, so I always ask them to take precaution to protect themselves and others. Novices are notorious for buying second hand gear when they are first starting out, and this is the reason why I continue with the face and back of the gauge facing away from people.
Good thinking Pug.
Just remember that both the face AND the back of an SPG are dangerous.
Consider telling them to just cover the gauge with their hand, a towel, dive bag or anything else at hand.
Thanks for watching.
Alec
So, should I press the second stage purge button when tuning on the thank?
Doesn't matter. You ought to press it to be sure it's working ok. That's all.
Alec
Got it! Also, I don't quiet understand when you mention "cover it completely". I should cover my spg by hand when I turn on the tank?
Do you mean that pressing second stage won't help protecting spg when turning on tank?
Not really. The second stage and the SPG are not directly related. The air for the SPG comes directly from the tank immediately as you turn on the valve. The air for the second travels through the first stage from the tank, is reduced and then along the LP hose to the second stage. Holding the purge down has no affect on the SPG.
The safest way to protect yourself from an SPG blowout is to simply put your hand, or a towel, bag, hood, what have you, over the face of the gauge as you turn on the air. In the very unlikely event that the SPG blows, nothing will fly up and hurt you.
Thanks for watching Huan.
Alec
Dear Alec,
I was taught that pressing the second stage purge to somehow protect the first stage in my OW course. Is that incorrect?
While incredibly rare, SPGs can still fail. Some modern SPGs don't have pressure relief plugs and some cheap SPGs may have relief plugs which don't work properly.
Best practise: Stick your SPG into your BCD while GENTLY tunring on air (turning it on too rapidly puts extra pressure on your system). This protects you (and others) from BOTH a front-face failure and the relief plug popping out.
As for the valves, yeah, don't turn them back a quarter-turn, or your friendly helpful DM/buddy might accidentally turn your air off instead of on during the pre-dive trips.
I have a scuba 'myths' coming out soon on this very subject Michael. Thanks for watching.
Hi Alec, My scubapro MK2 air gauge is reading more pressure, about 50bar more and I noticed its been flooded. Can I simply air dry the air gauge? the o ring outside the air gauge pop up when I turn on the tank pressure. please help :)
It's very tough to dry out an SPG.
You must keep the O-Rings on the swivel pin in good shape.
All you can do is remove the SPG head and set it in the sun for a couple of days. That might do it.
Blowing air into the open end is not much value since no air will actually penetrate the sealed gauge.
It can't be adjusted either so you'll have to live with the inaccurate reading.
Normally it will read the same overage at all times so it's working alright, just inaccurate..
Good luck.
Alec
Cheers dude - Top tips :-)
Thanks Mark. Alec
Amazing !!!.
Thanks for watching David.
Alec
Why in the catalog there is a page about guns? 4:47 - 4:48
Likely spear guns, which was arguably what made scuba-diving so popular back in the day.
what do you think of dacor pacerxl and 950
The DACOR Pacer 950 was one of the best regs ever made. I used one for years and wish they were still around, upgraded of course.
Alec
@@AlecPeirceScuba_SeaHunter thats what i have,can you rebuild them
Apeks Owners Manual:
If a submersible pressure gauge is attached to the first stage, ensure
that the gauge is facing away from you. Pressurise the regulator by
slowly turning the cylinder valve handwheel anti-clockwise. Continue to
turn the valve handwheel anti-clockwise until it is fully open, and then
turn it back 1/2 turn.
(Not disagreeing with your points, just interesting that manufacturers are stuck stating these things too...)
Either the Apeks gauge does NOT have a blow-out plug on the back (unlikely as most are made by the same company) or they are simply parroting the older diver manuals.
Thanks. Alec
So, they still call them "K-valves" simply because one particular catalog just happened to use "K" as the index number on the regulator IPB (illustrated parts breakdown)? That was some cool and interesting trivia!
I'd think, given this fairly compelling information, even the oldest, most seasoned diver or instructor would change their approach! But, people can be hard-headed. I know I'll put this bit of info to use in many activities - welding, using medical O2 for first aid, tire gauges, etc. as I suspect the same design changes apply to all kinds of pressure gauges. I really like the "extra" info you include in your videos to put things into perspective. Seriously some of the best RUclips how-to videos I've seen on any subject.
hi how are you please a share a video explain closed circuit sistem lar 3 diving
Look for a Homemade Rebreather video in my Vintage Scuba playlist.
That's probably as close as you'll get for now.
Thanks.
Alec
So is it bad to turn the valve 1/8-1/4 turn back? Or just unnecessary?
Not needed. It carried over from the 'stone age' to prevent the internals from seizing up. Does not happen with todays tank valves but causes more problems in verifying on/off.
@@AlecPeirceScuba_SeaHunter Great to know. We still do that with oxygen, acetylene, propane and the like. But, they use the same valves as 40 years ago. Some might even be that old.
All these tips you are telling me are wrong is all I remember from my dive course!
I did not deny that you were correct. You gave good and logical reasons - which I always like. However, I can still recall the serious attitude of the instructor on Koh Taoh, Thailand, in 1991, about turning the valve fully on and then back off slightly. He was also very serious about aiming the console away from yourself when you turned on the pressure. I also recall how we had to blow any water out of the dust cap with high tank pressure (you mentioned that was not nice in one of your tips, maybe a different video).
My point was most of the things you debunked covered almost all that I recalled so many years later. I thought that was funny.
I am enjoying your videos.
I have experienced a plastic pressure gauge explode taking out the front cover. This can happen. I like the final tip of facing the gauge away from you completely and turning your face away. I prefer to use the solid brass gauges. I feel they are much safer.
+John Llorens For several years I've used the Sherwood Wisdom, an air-integrated computer that is hose mounted, not wireless. It's been completely reliable and so easy to use. It's made scuba diving fun again!
Re the wireless models, I would have agreed 100% with you even as recently as 2 years ago but the latest models (Oceanic OCi, Sherwood Amphos Air, etc) are as reliable as Bourdon tubes and much more rugged. You can beat the heck out of an integrated circuit but not a Bourdon tube! And the connection seems constant now with no drops. They get better all the time. Soon you'll not be able to get a Bourdon tube gauge. Boy will my vintage collection be valuable then!!
Modern dive computers suffer from the same issue of rupturing the face as in the "50s and 60s." Check out the recall notices. Turning a tank value all the way open is not for the valve seat it is to prevent dethreading the knob by over torquing an already open valve. But, all students should turn the valve completely open as there is more risk of not having an open take than there is of breaking a knob. That "not hard" statement shows you understand this. The clip that holds the know on is not very strong.
I am not particularly strong but have broken more than a few knobs BTW. And, in a few thousand dives I have had one dive computer face explode. In front of a student. One her first check out dive.
Question:
Is there a valid reason why we don't dive with the cylinder valve at the bottom (Upside down) when mounted to the bcd where the valve is much easier to access than trying to reach up and behind your head? I realise you may require longer hoses, but, why don't we dive that way?
EMS and Fire Fighters use a similar system and their tanks are mounted valve down.
There were scuba systems like that. Check out earlier videos of mine to see one.The simple reason we don't use them in scuba is because we want the first stage to be as close as possible to the same level in the water as the second stage and your mouth and lungs.
The first stage delivers air at a pressure that varies with depth. Certainly with today's sophisticated regulators, it would be tough to tune a reg if the first stage was 2-3' deeper than the second. The pressure coming from the first would be too high. If you adjusted to compensate for that and then the diver went head down to look into a hole or something, he'd find it hard to breathe.
Plus don't forget that we have several hoses coming off the first stage - 1 to the Safe Second, 1 to the BCD, 1 to the SPG and maybe 1 to the dry suit. It could get messy back there with all those hoses going to different places on the diver's body. The current set-up seems to work well.
Thanks for watching.
Alec
I thought the half turn back was to stop people from forcing it the wrong way and breaking it.
Adam, you can't break a valve by turning it by hand. Have all of your air available: turn the valve all the way on, and never let anyone mess with it.
+Michael Ross hi guys, I am not a pro on what is inside the valve but you can break it if you do it to hard. you break the screws that hold the knob and the tank stays open or close depend where you force it. I know cuz I have done it ...
Usually what happens if your turn the knob too hard is that the plastic handle breaks. Then it will turn on the shaft but not turn the valve - the valve is stuck either open or closed. It's an easy fix. Remove the handle and replace it - total cost about $10. The worse problem is that you slowly ruin the sealing seat which will soon require the tank being drained and the valve rebuilt - total cost about $50! DON'T TURN THE VALVE HARD EITHER OPEN OR CLOSED. You can practice this with a tank that has no regulator on it. Open the valve slowly and carefully until air flows. The trun it slowly closed until the air flow stops - STOP TURNING!! That's it. When the air flow stops, the valve is closed. Get used to the feel. Take care. Alec
All adjustments on your regulator mounting and tank valve adjustment should be "hand-tight" only, not wrenched to the point of jamming. The seal in the valve itself is brass-on-brass, and it would take a clearly excessive amount of torque to damage the valve seat. The worst case scenario in this instance is that you'd have to have the valve overhauled (or better still, replaced with a 21st Century-era, stronger valve). You should never use "vintage" or off-brand equipment of any kind. Quality, up-to-date equipment will not be damaged by properly opening the valve all the way, as it always should be. However, the possibility of over-tightening the valve (by a rushed dive master or non-trained deck hand) is yet another reason not to let anyone else touch your gear, except a trusted buddy - ever.
@@AlecPeirceScuba_SeaHunter in a cave when you have to close a valve on a twin system to prevent losing 1 of the cylinders, a broken handle can cost you your life. I also teach the quarter turn back to prevent forcing the handle. What do you lose by turning a half turn back? Nothing. It has pros and no cons, so just do it. I agree the valve handle is cheap, but only if you're on land, underwater when you need to isolate on twins, it could be deadly.
I remember being looked down upon by older divers for not bothering to face my SPG away before opening the tank. I must say, I feel vindicated by this video.
You should Tom. There is the smart way and the way you were taught. At least we can be a little smug about it now, right!
When opening any valve all the way, I always turn it back a quarter turn or so; not to prevent sticking but to keep some bozo who comes along and turns it the same way for some reason and, thinking it stuck; cranks it harder and breaks it!
No one, I repeat, no one touches my tank once it's ready to dive.
That's what knives and speargns are for!!!
Look for my video on the Vindicator valve. It's in Series 1 and called "Air Check Is So Important" - best $20 you can spend.
Take care.
Alec
This is essentially what I was told the reason for turning it back a quarter turn was. I like the idea that nobody touches my gear once it is ready.
Have you ever seen a tank valve get knocked off?
Nope! Heard that it happens but I'm thinking that's rumor.
I've seen one get bent but it didn't break.
They're pretty tough.
It would take a heck of a bang to break off a modern valve.
Thanks for watching. Alec
The #1 thing scuba instructors teach that can hurt (kill) you is wearing too much weight. They teach incorrect technique that you should sink feet first after deflating your BC at the surface.
You use your fins and swim down, as your suit squeezes you will become negative at depth.
They teach to be negative at the surface with your gear on and the BC empty, this is incorrect.
You should be slightly positive at the surface, enough that your mouth and nose are out of the water with gear on and BC empty.
40% of dead divers wore too much weight. I wonder who taught them to wear too much?
Being negative at the surface is easier for the instructor - not necessarily best for the diver as you say Kim.
Certainly not for new divers.
Thanks. Alec
Usually - if you're using an aluminum tank you will likely be a few pounds more buoyant at the end of the dive. That causes it's own problems. Now you will find it had to stop and stay at 15 feet for a safety stop. If, as Kim says, you have correctly weighted yourself so you are barely buoyant at the surface with ALL the air out of your BC, it ought to be OK. If you're too buoyant it will be a frustrating dive, If you're too heavy it may not be safe. Now you understand better why PADI has an entire certification Specialty Course called Peak Performance Buoyancy where you learn and practice good buoyancy.
If you are in the tropics and falling off the end of a boat, there may never be an issue. If you are beach diving in Northern California, you better be able to swim at the surface. The PADI instruction for overweight diving is dangerous and wrong. "some tanks are positive when empty" well, that's a dive that's over. PADI until 2014 taught double drowning=buddy breathing with one second stage. My comment is intended for new divers to get some perspective that PADI is a club comprised of guys who claim to be experts.
I'm not here to defend any agency but, I am an instructor for 8 different agencies so have some perspective. PADI teaches positive buoyancy - floating at eye level with an empty BCD. Also they were the first to introduce the Safe-Second (octopus) as mandatory and the first to drop Buddy Breathing from the curriculum. No 'double drowning=buddy breathing' from PADI! And all this since the 90's, over 20 years. I don't want to argue with you Kim but please check your facts. Don't try to Trump me!
Let's hope that PADI knows what they're doing since currently almost 90% of all divers, dive stores and dive charters are PADI oriented.
As you say, location and environment can sure change things. What a diver does in Grand Cayman and what he does in California and what he does in Lake Simcoe, Ontario under the ice will be very different. It's pretty much impossible to have an incontrovertible rule for all situations but - it's equally impossible to train all divers for all situations!
Hi Alec, is that positive buoyancy newer in the curriculum? My two PADI courses, not counting refreshers, were in 1991 and 1992, but all the courses and most of the dives I have been on were not really compatible with the positive buoyancy as I recall the dive masters vertically in the water, and everyone just sinking while standing vertically after everyone give the down signal. If I had positive buoyancy, I would need to put my head down and my feet up to descend, wouldn't I?
Also, back then, in Australia I had seen some newly certified divers. They weren't just negatively buoyant, they would CRASH to the bottom and then pump a lot of air into the BDC. I guess I am overdue for a refresher by many years, so I will probably learn thin anyway.
😳
Oh yes. Lots of 'stone age' practices still being taught to new divers that don't apply anymore (eg turning the valve 1/4 back from full on). Lots to learn.
I would rather do what I was taught
+Daniel Mckell
You're not wrong in that respect Daniel. I wouldn't suggest that your instructor lied to you.
However, I've been teaching scuba since 1969 and a lot of things have changed in all those years. So, what you're instructor learned and thus teaches in his classes, may not be the best information based on newer research or newer scuba gear.
Scuba 2000 is a very busy dive facility. We have 43 instructors on staff and one of my jobs is to keep them up-to-date. Many instructors do not teach very often and many have not updated their teaching information or methods despite all of the changes in scuba diving.
An example is the teaching of Buddy Breathing. It was a mandatory skill for many years but has not been longer taught to new dive students for several years for good reason. Some instructors continue to teach Buddy Breathing. They either have not updated their course or they don't recognize the importance of removing that outdated skill from their class.
I am simply suggesting that some things which were common knowledge and thus commonly taught in scuba classes for a long time are no longer accurate.
With that in mind, perhaps you could check out some of these ideas on the internet rather than blindly accepting my ideas or those anyone else.
Thanks for your comment.
Alec
+Daniel Mckell Even if it's stupid? I mean no offense, but if you're taught something wrong, why continue doing it that way when someone else comes along and gives a very good reason not to do it that way?
Brother-Diver Oscar, I was thinking the very same thing as you!
I've been an instructor for quite some time and I do not disagree with you, but you say this like it is a fact. It is not. For example, a normal SPG used for techincal diving has no over pressure valve on the back, meaning it can face with the back, rather than the front, because that is where the glass or plastic will hurt you.
Same goes with all the way on and half a way back. For ME, that is so a student don't start turning the knob on and the knob is att 100, and missing the thread, making it more or less impossible to close without tools. And for the red and green marker... I've been all around the world and made 2000+ dives and have NEVER seen that before, so do not talk about it like it is default config.
Björn Jakobsson So true i use a technical configuration including spg made of metal with no pressure relief valve and even before when I used a normal confirmation I never seen a plastic spg or a pressure relief valve or a green red thing!
Alec for instructors a green red thing really? Isn’t it better that new divers learn by heart they’re buddy check procedures buckles valves releases air final check and they each buddy up with someone and they check each other’s gear in stead of the instructor just looking see if it’s green and that’s it.and what you said about every SPG having a pressure relief valve is simply not true a technician metal SPG has no pressure relief valve on the back the only way for pressure to be relieved is trough the weakest part the glass or plastic screen on the SPG !
Anybody else like me here on this thread think that both Bjorn Jakobsson and Darren Fay are just a couple of argumentative twinkies that just LOVE to spout "contrary?"
Dumbass