Mike,
I feel your pain...I am going on three trips to NC in the next 3 months and probably will be doing some of the same wrecks you will be doing. Right now I am going with option B.
Pony Bottle pros & Cons
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Mike,
I feel your pain...I am going on three trips to NC in the next 3 months and probably will be doing some of the same wrecks you will be doing. Right now I am going with option B.
tchil01,
The Advanced Nitrox that we teach (IANTD) introduces redundant equipment and decompression procedures. The student uses an H valve or doubles. The sling tank that is used is for deco (or safety stop) gas. This course has a max depth of 130 and allows only minimal (required) staged deco. However with some redundancy proper gas management and the ability to do a few minutes of staged deco you may find yourself having enough time and confidence to relax and really enjoy a 100ft+ dive for the first time. And all without a pony.
Mike
The Advanced Nitrox that we teach (IANTD) introduces redundant equipment and decompression procedures. The student uses an H valve or doubles. The sling tank that is used is for deco (or safety stop) gas. This course has a max depth of 130 and allows only minimal (required) staged deco. However with some redundancy proper gas management and the ability to do a few minutes of staged deco you may find yourself having enough time and confidence to relax and really enjoy a 100ft+ dive for the first time. And all without a pony.
Mike
MikeS,
You are correct. You would usually need to travel with your own tanks or dive with an outfit that has that equipment available. There are getting to be more and more of them.
With an H valve - If a reg free flows you shut it down and switch regs. This is something you will practice in a class of this level. You will be confident in your ability to easily shut it down fast enough. It is possible that a burst disk could go. Manifolded doubles takes care of that. With an H-valve you need help. I have seen them leak on a dive but not blow all out. I have never seen a tank o-ring go.
One of my main points here is that I think (I'm not alone) this is the correct equipment for dives of this type. Operators that provide these dives without the right equipment should be avoided.
Lets say you do a 120 ft wreck dive with a pony. There is a bunch of current so you want to surface on the line. You plan your gas so you can go down the wreck and back, ascend, do a few minutes deco or safety stop and still surfase with a reserve left in your tank. At the furthest point in the dive you blow the yolk valve 0-ring (something I have seen) on you single output valve. You switch to the pony. Now your gas plan is shot to pieces. You may have to ascend where you are. Even shooting a bag this isn't good. You may drift a long way before the boat can come get you. You may land in Cuba. Your buddy will not enjou the ride. Or in your hast to ascend do you get seperated? With the H-valve you hopefuly have din avoiding the o-ring problem. So..lets say it was a free flow or a busted hose. You shut it down and switch regs. You used part of the reserve you planned in but you can still make it back to the line. Your gas plan is still in effect. You get to the line and ascend normally. Once you hit 70 ft you switch to your sling tank (which has 50% in it) A short stop or two brings you and your buddy right back to the boat as planned instead of drifting away in the cold.
Mike
You are correct. You would usually need to travel with your own tanks or dive with an outfit that has that equipment available. There are getting to be more and more of them.
With an H valve - If a reg free flows you shut it down and switch regs. This is something you will practice in a class of this level. You will be confident in your ability to easily shut it down fast enough. It is possible that a burst disk could go. Manifolded doubles takes care of that. With an H-valve you need help. I have seen them leak on a dive but not blow all out. I have never seen a tank o-ring go.
One of my main points here is that I think (I'm not alone) this is the correct equipment for dives of this type. Operators that provide these dives without the right equipment should be avoided.
Lets say you do a 120 ft wreck dive with a pony. There is a bunch of current so you want to surface on the line. You plan your gas so you can go down the wreck and back, ascend, do a few minutes deco or safety stop and still surfase with a reserve left in your tank. At the furthest point in the dive you blow the yolk valve 0-ring (something I have seen) on you single output valve. You switch to the pony. Now your gas plan is shot to pieces. You may have to ascend where you are. Even shooting a bag this isn't good. You may drift a long way before the boat can come get you. You may land in Cuba. Your buddy will not enjou the ride. Or in your hast to ascend do you get seperated? With the H-valve you hopefuly have din avoiding the o-ring problem. So..lets say it was a free flow or a busted hose. You shut it down and switch regs. You used part of the reserve you planned in but you can still make it back to the line. Your gas plan is still in effect. You get to the line and ascend normally. Once you hit 70 ft you switch to your sling tank (which has 50% in it) A short stop or two brings you and your buddy right back to the boat as planned instead of drifting away in the cold.
Mike
tchil01
Guest
Mike
My only disagreement is that here in the NE we are taught to tie a lift bag off using a Jersey reel before assending. That way you don't end up in Cuba... The Jersey Reel has sissal rope so when you cut the bag away the rope biodegrades.
Ty
MikeF,
Based on your description of floating to Cuba I have decided to only dive with a Spanish-speaking buddy.
But seriously, I think that you have missed the point of my question. Based on your description using an H-valve has some advantages over a pony. Im still not totally convinced. Not that I dont respect your opinion, quite the contrary is true, its just that Im hard headed and sometimes it takes a while to sink in. The two remaining unresolved issues I have with H-valve versus pony are:
How hard is it to reach and manipulate an H-valve behind you versus a pony bottle right in front of you? Guess I would have to try it.
What about the advantage of being able to hand off the pony? It seems there are situations where this is a good thing.
But at this point its mute because I am not willing to spend the money and dont have the time (for training with the new hardware) before the trip to NC. It seems to me that equipment configuration and training are ways to mitigate the risk of diving. To eliminate the risk of diving related injuries you have to stay out of the water! So the key is to get as much training as practical and buy the safest equipment configuration as practical (non to be confused with possible). At that point you have to decide is the remaining risk acceptable, if not dont make the dive.
So back to the case in point, my question if you will, is it not safer to dive with a pony (with which Ive practiced in the quarry), than diving without one, based on the facts that Im going one way or another and an H-valve approach is not practical.
I dont think that safety is a black and white question, I think it's many shades of gray. On one extreme you could buy equipment on E-bay and make the dive with no training. You would probably live but there is a very significant chance of injury. Moving toward the other end of the scale are PADI standards (not to pick on them) that say if you have AOW get a site briefing your O.K. Then at the total extreme if I were a multibillionaire I could buy a submersible habitat with a rescue staff on board to follow me around underwater.
While an H-valve approach may be safer, and dual tanks with an isolation manifold even safer, at this point neither of those options are practical. Ive tried to minimize the risk as much as possible and now believe the risk is acceptable.
Ty,
Can you supply a link to more information on a Jersey Reel? This sounds suspiciously like a square dance.
Thanks,
Mike
Based on your description of floating to Cuba I have decided to only dive with a Spanish-speaking buddy.
But seriously, I think that you have missed the point of my question. Based on your description using an H-valve has some advantages over a pony. Im still not totally convinced. Not that I dont respect your opinion, quite the contrary is true, its just that Im hard headed and sometimes it takes a while to sink in. The two remaining unresolved issues I have with H-valve versus pony are:
How hard is it to reach and manipulate an H-valve behind you versus a pony bottle right in front of you? Guess I would have to try it.
What about the advantage of being able to hand off the pony? It seems there are situations where this is a good thing.
But at this point its mute because I am not willing to spend the money and dont have the time (for training with the new hardware) before the trip to NC. It seems to me that equipment configuration and training are ways to mitigate the risk of diving. To eliminate the risk of diving related injuries you have to stay out of the water! So the key is to get as much training as practical and buy the safest equipment configuration as practical (non to be confused with possible). At that point you have to decide is the remaining risk acceptable, if not dont make the dive.
So back to the case in point, my question if you will, is it not safer to dive with a pony (with which Ive practiced in the quarry), than diving without one, based on the facts that Im going one way or another and an H-valve approach is not practical.
I dont think that safety is a black and white question, I think it's many shades of gray. On one extreme you could buy equipment on E-bay and make the dive with no training. You would probably live but there is a very significant chance of injury. Moving toward the other end of the scale are PADI standards (not to pick on them) that say if you have AOW get a site briefing your O.K. Then at the total extreme if I were a multibillionaire I could buy a submersible habitat with a rescue staff on board to follow me around underwater.
While an H-valve approach may be safer, and dual tanks with an isolation manifold even safer, at this point neither of those options are practical. Ive tried to minimize the risk as much as possible and now believe the risk is acceptable.
Ty,
Can you supply a link to more information on a Jersey Reel? This sounds suspiciously like a square dance.
Thanks,
Mike
Jersey Reel
A large spool of rope used to provide a decompression line in case of emergency or in a contingency when divers choose or are prevented from returning to the anchor line for open water ascent. The reel uses 1/4 inch sisal line that will eventually bio-degrade. The divers use the spool to float a lift bag and then attach the rope to a stable object such as the wreck frame or large rock on the bottom.
Here's a link to a picture of one.
I looked around for more info, but couldn't find any that was worth anything...basically instead of shooting a bag and doing a floating deco, you attach the line to the wreck or run it under a railing or something before shooting it. That way, you are basically making your own ascent line and you are right on the wreck so the boat can find you easily instead of drifting in the NE currents like you might doing a drifting deco.
IMHO, the boat you are diving from should have a chase boat so you would not need a Jersey Upline/Reel whatever, but in the NE anything can happen...
A large spool of rope used to provide a decompression line in case of emergency or in a contingency when divers choose or are prevented from returning to the anchor line for open water ascent. The reel uses 1/4 inch sisal line that will eventually bio-degrade. The divers use the spool to float a lift bag and then attach the rope to a stable object such as the wreck frame or large rock on the bottom.
Here's a link to a picture of one.
I looked around for more info, but couldn't find any that was worth anything...basically instead of shooting a bag and doing a floating deco, you attach the line to the wreck or run it under a railing or something before shooting it. That way, you are basically making your own ascent line and you are right on the wreck so the boat can find you easily instead of drifting in the NE currents like you might doing a drifting deco.
IMHO, the boat you are diving from should have a chase boat so you would not need a Jersey Upline/Reel whatever, but in the NE anything can happen...
MikeS,
Using a pony is not, in my view, a dangerous act in itself. But there are lots of problems that it doesen't address. As far as the ease of manipulating valves that are behind you, that is a skill which should be developed and is a major part of the training I mentioned. Gas management is one of the most critical parts of dive planning and redundancy in the primary gas supply lends itself to that best. It is not uncommon to stage or carry extra gas for risky dives. The principal is similar to using a pony in that it is strictly a reserve. However, this is not a substitute for primary gas redundancy (doubles or H-valve). With all that said, if the decision to make a dive has been made and redundance is desired and a pony was the only choice then...I suppose it's better than nothing. Even then I would prefer it be big enough to get me back from the furthest point in the dive. I realize that under some conditions it is ok to go streight to the surface but not always.
I haven't used a jersey reel but when diving open water we carry a lift bag and reel or spool. If we must ascend in open water (away from the boat) or if the plan calls for a drifting ascent/deco the bag is deployed providing a surface marker. Some divers carry multiple bags. The bags are color coded and convey a messege to the surface crew. One color may mean "I ascending away from the boat but I'm ok". Another color may mean that you need additional gas (need help).
BTW it was a trip ti NC and a dive on the Papoose that first got me thinking I needed a pony. The current was bad (several days of bad weather had just passed) so we had to stay down current behind the wreck. We were at about 120 with al 80's. The dive was short and maybe a little scary. Now we are much better prepared and this would be a long relaxing enjoyable dive.
Have a good trip
Mike
Using a pony is not, in my view, a dangerous act in itself. But there are lots of problems that it doesen't address. As far as the ease of manipulating valves that are behind you, that is a skill which should be developed and is a major part of the training I mentioned. Gas management is one of the most critical parts of dive planning and redundancy in the primary gas supply lends itself to that best. It is not uncommon to stage or carry extra gas for risky dives. The principal is similar to using a pony in that it is strictly a reserve. However, this is not a substitute for primary gas redundancy (doubles or H-valve). With all that said, if the decision to make a dive has been made and redundance is desired and a pony was the only choice then...I suppose it's better than nothing. Even then I would prefer it be big enough to get me back from the furthest point in the dive. I realize that under some conditions it is ok to go streight to the surface but not always.
I haven't used a jersey reel but when diving open water we carry a lift bag and reel or spool. If we must ascend in open water (away from the boat) or if the plan calls for a drifting ascent/deco the bag is deployed providing a surface marker. Some divers carry multiple bags. The bags are color coded and convey a messege to the surface crew. One color may mean "I ascending away from the boat but I'm ok". Another color may mean that you need additional gas (need help).
BTW it was a trip ti NC and a dive on the Papoose that first got me thinking I needed a pony. The current was bad (several days of bad weather had just passed) so we had to stay down current behind the wreck. We were at about 120 with al 80's. The dive was short and maybe a little scary. Now we are much better prepared and this would be a long relaxing enjoyable dive.
Have a good trip
Mike
Anyone know of any mail order shops who sell H-valves on them?
I have yet to see anyone offering them for sale. I'd like to buy one - sure would be a whole lot cheaper to purchase an H-valve rather than a 30 or 40 cu in bottle, 1st and 2nd stage, PSI gauge, hose clamps and rigging, annual VIP and reg servicing.
????
I have yet to see anyone offering them for sale. I'd like to buy one - sure would be a whole lot cheaper to purchase an H-valve rather than a 30 or 40 cu in bottle, 1st and 2nd stage, PSI gauge, hose clamps and rigging, annual VIP and reg servicing.
????
Scubaroo
Contributor
www.divesales.com, www.leisurepro.com...
Thermo, OMS and Dive Rite all make H valves.
You'll still need another 1st stage, and a H valve isn't something you can just screw onto a rental tank - you'll need your own tank. You'll also need a modular K valve on the tank that is compatible with the H valve you buy.
Thermo, OMS and Dive Rite all make H valves.
You'll still need another 1st stage, and a H valve isn't something you can just screw onto a rental tank - you'll need your own tank. You'll also need a modular K valve on the tank that is compatible with the H valve you buy.
Spectre
Contributor
Single vs. Doubles...
I've been doing a few dives lately where just about everyone in the group is diving doubles. I've been thinking about doubles for a while, and working my way in that direction. However, I've been thinking about it a lot lately, and I've got more questions. I was going to start a new thread, but since it is so closely related to this one, I thought I'd try to open this one back up.
Here's the thing. Currently I dive singles with a pony [attached to my primary tank, but moving it to stage bottle style shortly most likely]. I like the comfort that I have a fully independant bail out which has plenty of gas to ascend to the surface very slowly in the case of a catastrophic failure of my primary system.
Now doubles sorta gives the same security, except for two things. 1) it comes down to timing... you still have to isolate your tanks in the event of a catastrophic failure... so the amount of backup gas you have is directly proportional to how fast you get it isolated. 2) On your first dive, you have plenty of gas to get things shut down and still get to the surface at a leisurely pace. However it seems that almost everyone that dives doubles, does two dives on a set.
So how is doing two dives on a set of 100 cuft doubles safer than doing two dives with 100 cuft tanks, switching the tanks in between, while still having the bail out bottle for insurance on both dives? A full single 100 cuft tank + a pony bottle seems to me to be a safer option than the second dive on a set of doubled 100s.
So I'm obviously missing something... what is it I'm missing?
I've been doing a few dives lately where just about everyone in the group is diving doubles. I've been thinking about doubles for a while, and working my way in that direction. However, I've been thinking about it a lot lately, and I've got more questions. I was going to start a new thread, but since it is so closely related to this one, I thought I'd try to open this one back up.
Here's the thing. Currently I dive singles with a pony [attached to my primary tank, but moving it to stage bottle style shortly most likely]. I like the comfort that I have a fully independant bail out which has plenty of gas to ascend to the surface very slowly in the case of a catastrophic failure of my primary system.
Now doubles sorta gives the same security, except for two things. 1) it comes down to timing... you still have to isolate your tanks in the event of a catastrophic failure... so the amount of backup gas you have is directly proportional to how fast you get it isolated. 2) On your first dive, you have plenty of gas to get things shut down and still get to the surface at a leisurely pace. However it seems that almost everyone that dives doubles, does two dives on a set.
So how is doing two dives on a set of 100 cuft doubles safer than doing two dives with 100 cuft tanks, switching the tanks in between, while still having the bail out bottle for insurance on both dives? A full single 100 cuft tank + a pony bottle seems to me to be a safer option than the second dive on a set of doubled 100s.
So I'm obviously missing something... what is it I'm missing?
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