 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
| HomeArticlesDiving DestinationsLearning Scuba DivingMarine LifeMiscellaneousDiscussion GroupsGeneralScuba EquipmentScuba LocationsAustralian ScubaUK ScubaDirectoryScuba Clubs |
Scuba Forum / General / May 2004Poll: Doubles with Isolator Manifold
Switching to a doubles config in a week or two and would like some "help" staying alive. :) I have twin steel 80s with an isolator manifold, SS backplate (OMS), dual bladder (OMS; 100lb lift). (I also own a 19 cu ft pony that I might add to the mix depending on my research here and elsewhere.) I dive wet in Ontario as long as the water surface is liquid. I have about 130 dives logged so I consider myself an "advanced beginner". I don't do caves or penetrate wrecks; no overhead stuff. (Well, okay, some easy wreck penetration sometimes. No tight fits. No more than one turn. And never very far in. [Nothing I'd need a reel for.]) What are your thoughts on.... 1) SPGs (1 or 2?) 2) Connecting both bladder inflators (as opposed to leaving the backup bladder inflator disconnected unless needed) 3) Leftness/rightness of BC whips/second stages (eg. primary reg on same post as secondary BC whip) 4) Manifold failures...is a catastrophic failure likely/possible? By that I mean, even closing the isolation valve does not prevent loss of all breathing gas from both tanks. I'll donate my gear to the person who gives the best advice, should I die while following that advice on any even day of the month. > Switching to a doubles config in a week or two and would like some "help" > staying alive. :) [quoted text clipped - 22 lines] > I'll donate my gear to the person who gives the best advice, should I die > while following that advice on any even day of the month. www.northerntechdiver.com Brian Edmonton, Alberta www.mossmanscuba.com How can we be sure you died on an even day? Lee > Switching to a doubles config in a week or two and would like some "help" > staying alive. :) [quoted text clipped - 22 lines] > I'll donate my gear to the person who gives the best advice, should I die > while following that advice on any even day of the month. > How can we be sure you died on an even day? > > Lee Ooohhh, sharp :-) [\]Robert Wood The St. Lawrence River - fresh, warm, visible diving. mailto:rgwood@magma.ca No offense Larry, but your a cluster waiting to happen. You need to get with aqualified instructor or experienced doubles diver.. learn from them and get rigged correctly. In the meantime-- > I have twin steel 80s with an isolator manifold, good SS backplate (OMS) passable , dual > bladder (OMS; 100lb lift). JUNK (I also own a 19 cu ft pony that I might add to > the mix depending on my research here and elsewhere.) True Junk - ditch it now I have about > 130 dives logged so I consider myself an "advanced beginner". No, at 130 dives you are a beginner, nothing more and nothing less. Get to 500 real dives and then consider checking into training to use doubles. > And never > very far in. [Nothing I'd need a reel for. That statement alone means you need training. > 1) SPGs (1 or 2?) 1... either it is reading the correct pressure for both tanks or your hauling a.s after a major screwup and you really don't want to know how little air you have left. You either have enough to get to the surface or it don't matter anyway! > 2) Connecting both bladder inflators (as opposed to leaving the backup > bladder inflator disconnected unless needed) Get rid of one bladder and one inflator. Your just adding to the mess. Use your drysuit as backup bouyancy. > 3) Leftness/rightness of BC whips/second stages (eg. primary reg on same > post as secondary BC whip) Read http://www.wkpp.org/articles/Gear/newgeorge.html I'm not DIR but their gear configuration is excellant. Read it, understand it and then get trained properly. > 4) Manifold failures...is a catastrophic failure likely/possible? Not likely but anything is possible. > I'll donate my gear to the person who gives the best advice, should I die > while following that advice on any even day of the month. Unless you get some training, there is a chance you just may be doing that (or at least your survivors will). Diving with doubles is more than just putting another tank on and jumping in the water... Ron > consider checking into training to use doubles. Nawh... Just strap 'em on and jump in the water.. You'll figure out soon enough what works and what doesn't... We don't need no stinkin' instruction... Hell, instruction just gets in the way of Darwin doin' his job anyway... >Diving with doubles is more than just putting another tank on and >jumping in the water... Ya... it's hauling another tank back up the ladder when the dive is over! --- Rich http://richlockyer.tripod.com/ The message <c7resf$dj4$1@news.ryerson.ca> from "Larry Anta" <lanta@ryerson.ca> contains these words: > I have twin steel 80s with an isolator manifold, SS backplate (OMS), dual > bladder (OMS; 100lb lift). (I also own a 19 cu ft pony that I might add to > the mix depending on my research here and elsewhere.) Hmm, I think I'm falling for a troll > I dive wet in Ontario as long as the water surface is liquid. I have about > 130 dives logged so I consider myself an "advanced beginner". I don't do > caves or penetrate wrecks; no overhead stuff. (Well, okay, some easy wreck > penetration sometimes. No tight fits. No more than one turn. And never > very far in. [Nothing I'd need a reel for.]) > What are your thoughts on.... Do a search on the techdiver archives if they're still accessible, its all well documented, and almost all the differing groups agree > 1) SPGs (1 or 2?) 1 > 2) Connecting both bladder inflators (as opposed to leaving the backup > bladder inflator disconnected unless needed) Nope, I'd change the wetsuit for a drysuit, assuming you're doing a dive long enough to justify twins, then change to an oxycheq or similar wing with no bungees anywhere ( bad experience going back a few years) and have one wing backed up by a drysuit > 3) Leftness/rightness of BC whips/second stages (eg. primary reg on same > post as secondary BC whip) Have both 2nds coming over your right shoulder, the primary on a long hose, the secondary held in. Wing inflate on the LHS, suit inflate in the right, keeps the hoses neatest and most streamlined > 4) Manifold failures...is a catastrophic failure likely/possible? By that I > mean, even closing the isolation valve does not prevent loss of all > breathing gas from both tanks. Never run accross one, however I've personally had to do a shutdown on one reg, and been glad of access to all my gas after a freeflow at 68m on the secondary > I'll donate my gear to the person who gives the best advice, should I die > while following that advice on any even day of the month. Umm, no thanks >Switching to a doubles config in a week or two and would like some "help" >staying alive. :) > >I have twin steel 80s with an isolator manifold, These would be better suited for beginner cave diving with the use of a dry suit. If you are diving wet with steel tanks, if you experience a BCD failure at depth, wetsuit compression and a water filled BCD will make swimming up with the tanks far more difficult than if you dove in a drysuit. What kind of manifold? SS backplate (OMS) Are you using one continuous piece of webbing + crotch strap? , dual >bladder (OMS; 100lb lift). Extra drag & extra problems for no reason. (I also own a 19 cu ft pony that I might add to >the mix depending on my research here and elsewhere.) Keep the valve, ditch the bottle & then get a properly sized argon bottle for your drysuit. >I dive wet in Ontario as long as the water surface is liquid. Go dry with steel tanks. I have about >130 dives logged so I consider myself an "advanced beginner". I don't do >caves or penetrate wrecks; no overhead stuff. (Well, okay, some easy wreck >penetration sometimes. No tight fits. No more than one turn. And never >very far in. [Nothing I'd need a reel for.]) I became a cave diver after some tech training to be able to visit cave systems and become a better wreck diver. Thanks to my GUE instructors & training I had thigh pockets on my drysuit in which I kept a backup mask. On dive one of the cavern portion of the course, my cave instructor took me through a trainer with just a couple of easy turns and a drop through a hatchway while running line. He then ripped off my mask. I locked the reel and set it for an exit by touch contact with my buddy. Without the reel I wouldn't have known where the heck I was. My buddy broke off touch contact & I waited for him to reestablish. Nothing. I then began to follow the line out when I hit the hatchway like restriction. I had doubles on and couldn't quite twist the right way to get out. I kept banging the manifold. I tried & tried, then stopped, hoping for buddy assistance by touch from my buddy or my instructor. Nothing. "Ok, I quit," I thought to myself, "I have no idea what's going on, so I'm going to find out even if it's cheating." I reached into my pocket deployed my backup mask & figured out how to squeeze through the restriction. Upon surfacing, I apologized to my instructor for presumably screwing up. He said, "What are you talking about? You're the only one who lived. You found your way out right? These 3 died. You were the only one with a backup mask. The point being that those one or two easy turns in a wreck can end up killing you without proper training & precautions. I'll never go in a wreck without running a continuous guideline out to open water or without a back up mask. That lesson in the trainer to see how something that looked so easy, but could become confusing was worth the cavern course alone. The rest of the course was even more educational. >What are your thoughts on.... > >1) SPGs (1 or 2?) 1 >2) Connecting both bladder inflators (as opposed to leaving the backup >bladder inflator disconnected unless needed) Only use a single bladder wing without a bungee system. >3) Leftness/rightness of BC whips/second stages (eg. primary reg on same >post as secondary BC whip) 7 ft primary reg from right post. BCD LP inflator from right post. back up regulator on shock cord around your neck from left post. SPG from left post. >4) Manifold failures...is a catastrophic failure likely/possible? By that I >mean, even closing the isolation valve does not prevent loss of all >breathing gas from both tanks. Anything is possible. Train for both the imposible & the improbable so when they happen you can handle it. >I'll donate my gear to the person who gives the best advice, should I die >while following that advice on any even day of the month. Best advice. Take DIR-F and then a cave course for any wreck diving. It will put you ahead of the majority of divers out there and help keep you alive. Trace Malinowski PDIC Instructor #2075 Freediving Instructor Trainer Larry, where are you? Eastern Ontario? Thoughts annotated: > Switching to a doubles config in a week or two and would like some "help" > staying alive. :) > > I have twin steel 80s with an isolator manifold, SS backplate (OMS), dual > bladder (OMS; 100lb lift). (I also own a 19 cu ft pony that I might add to > the mix depending on my research here and elsewhere.) Drop the dual bladder - that other LP inflator gets in the way. Drop the 19 cuft pony - there are sling bottles of greater size. > I dive wet in Ontario as long as the water surface is liquid. Don't dive wet with twins. Check my website http://www.magma.ca/~rgwood/buoy.html to see an analysis of buoyancy. People have died doing this. > I have about > 130 dives logged so I consider myself an "advanced beginner". I don't do [quoted text clipped - 5 lines] > > 1) SPGs (1 or 2?) Just one. > 2) Connecting both bladder inflators (as opposed to leaving the backup > bladder inflator disconnected unless needed) See my earlier comment. > 3) Leftness/rightness of BC whips/second stages (eg. primary reg on same > post as secondary BC whip) > 4) Manifold failures...is a catastrophic failure likely/possible? By that I > mean, even closing the isolation valve does not prevent loss of all > breathing gas from both tanks. Exactly .. that's what the isolator is for. But mind you, you have to practive turnin it on and off. > I'll donate my gear to the person who gives the best advice, should I die > while following that advice on any even day of the month. Well, I won't win your gear then :-) [\]Robert Wood The St. Lawrence River - fresh, warm, visible diving. mailto:rgwood@magma.ca > 1) SPGs (1 or 2?) Well, considering the fact that we used to dive with zero, one should be plenty of backup for your J-valves... >I dive wet in Ontario as long as the water surface is liquid. I have about Dump the wetsuit and the 100lb dual bladder. Unless you're carrying several steel stage bottles, you don't need more than 55 pounds of lift. Even with a couple of steel stages, 70 would be plenty of lift. >1) SPGs (1 or 2?) One, connected to the left post (above your left shoulder) Dive with the isolator valve ALWAYS open... and make sure that it is open before AND after you get an air fill. I know of a guy who took a set of doubles and a deco bottle into an unfamiliar shop for a fill. He asked for a 50% deco mix and 21/35 trimix in the doubles. He got 50% in the 40cf bottle, but in the doubles, he had AIR in one tank and EAN35 in the other tank. Well, it was 21/35. >2) Connecting both bladder inflators (as opposed to leaving the backup >bladder inflator disconnected unless needed) Leave the backup disconnected. If one of the inflators starts to leak, you have no way of knowing which one it is... and you may not even know that it IS leaking... until you've dumped (what you think is) all if your gas and are still rising. Yes... connecting the backup BC is a pain, especially in cold water with gloves hands, but you do need backup buoyancy. Considering the conditions, a drysuit would work well. If you're a big guy, I might be able to make you a good deal on an XL TLS350 if the guy I'm working with right now doesn't want it. Nothing wrong with it... I started working out and will now fit into a medium, and am preparing to order a cave cut. >3) Leftness/rightness of BC whips/second stages (eg. primary reg on same >post as secondary BC whip) Everything on the right is primary. Everything on the left is backup. The main reason for this is related to cave/wreck, because contact will roll the right post off, but roll the left post on. If a knob breaks off due to contact, the left post will be on and the right will be off. You ALWAYS want your backups available. This is also why the SPG is on the left post. An SPG on the right post begins to clutter the rig, and for what purpose? If will provide pressure information on the right tank in the event that you had a failure on the left tank and had to isolate. #1 - This is a remote possibility. #2 - At the point of failure, the dive is over #3 - You either have, or do not have enough gas to safely surface. An SPG attached to the tank will not change that. If it's a deco dive, hopefully you are carrying deco gasses in separate cylinders, attached to your rig. Worst case, you grab your buddy's backup until you hit your first stop if you DO run out, and use his backup for your air breaks if the deco is long enough. #4 - The HP hose, O-rings, and SPG themselves add several additional failure points. Following this logic, if you do switch to a drysuit, whether you use argon or air for inflation, a separate 6-13cf bottle, either hip or plate mounted, is a good idea. It gets a hose off of your back gas, and failure of either post will not affect your ability to inflate the suit. >4) Manifold failures...is a catastrophic failure likely/possible? By that I >mean, even closing the isolation valve does not prevent loss of all >breathing gas from both tanks. Extremely remote. Closing the isolation valve will isolate all of the failure points. Even a blown tank neck O-ring or burst disk will not empty both tanks with the valve closed, however, you only have a few seconds to get that valve closed before dropping a good part of your gas supply... HOWEVER... burst disk and tank neck/manifold failures are relatively uncommon (except perhaps after a HARD contact). The most likely failure is going to be a freeflowing reg. In this case, you can hear which side the bubbles are coming from. Shut down THAT post. If the bubbles don't stop, then you've lost an O-ring or burst disk and you need to shut down the isolator. Now that the isolator is shut down, and you know that, for example, your right post just blew, then you know that you have a very limited supply of gas in that cylinder and need to go to your backup regulator, and backup buoyancy source. I can't think of a scenario (short of a HARD impact) where a SINGLE failure could result in the loss of gas from both tanks. You would have to have two failures, one on each side of the isolator, and both failures of the least likely type (burst disk or tank neck/manifold o-ring) --- Rich http://richlockyer.tripod.com/ >>I dive wet in Ontario as long as the water surface is liquid. I have about > > Dump the wetsuit and the 100lb dual bladder. Unless you're carrying > several steel stage bottles, you don't need more than 55 pounds of > lift. Even with a couple of steel stages, 70 would be plenty of lift. I dive double (steel) 7's with a 40 lb wing. It gives me more than enough lift. Even double 10's won't give me problems. 100lb is indeed a huge overkill. >>1) SPGs (1 or 2?) > [quoted text clipped - 20 lines] > wrong with it... I started working out and will now fit into a medium, > and am preparing to order a cave cut. From XL to M? Congrats!  SignatureMichael Wolf ----- Cthulhu For President. Why settle for the lesser evil? remove stopspam to reply >> Dump the wetsuit and the 100lb dual bladder. Unless you're carrying >> several steel stage bottles, you don't need more than 55 pounds of [quoted text clipped - 4 lines] > >100lb is indeed a huge overkill. Absolutely. The Explorer 70 was made with European divers in mind who have a hard time getting Luxfer stages. It is obvious how "overkill" these huge bladders are when you run the numbers. Your body is going to be, at worst, neutral, even in a flooded drysuit. This means that you are... worst case... negative by the amount of ballast plus tanks plus gas in those tanks. So if you're diving double 104's on a cave fill, and you are diving air, you're carrying a little over 20 pounds of gas. 20, Check. Add to that the empty buoyancy of the 104s. Depending on when they were made, anywhere from -2 to -5 pounds each. Again... worst case, -10 20+10=30. Check. If your body is so dense that you are neutral, then your only ballast needed is to offset the buoyancy of your suit. A 6 pound stainless plate should suffice. 20+10+6=36. Check. Throw in a couple of Luxfer 80 stages. Full, that's another 3 pounds each. 20+10+6+6=42. Check. Yup. A 45 pound wing should be more than adequate. Add to this the fact that you would only need all 45 pounds of lift at the beginning of the dive when all four tanks are full, and if you lose all buoyancy in your suit. You will be burning off at least 20-25 pounds of gas during the dive, so if properly weighted, you'll be neutral with no gas in the wing at the end of the dive. >> If you're a big guy, I might be able to make you a good deal on an XL >> TLS350 if the guy I'm working with right now doesn't want it. Nothing >> wrong with it... I started working out and will now fit into a medium, >> and am preparing to order a cave cut. > > From XL to M? Congrats! I actually fit the large pretty well, but needed a little more room for my hips to be comfortable. Good move, as I actually gained 10 pounds between the time I bought the suit and the next year or so. Moderate diet changes shed that extra 10, but then I plateaued at about 210 with a body fat level of nearly 28%. I'm now flirting with 195, and body fat hovering between 17 and 20%, depending on the time of day. I'm sure my cave cut will actually be a bit larger than a medium. While I fit into the suit, it was wearing jeans and a T-shirt, and I did have trouble getting my left elbow past the zipper when I tried to take it off. Sure felt comfy though! I'm really looking forward to getting a truly properly fitting suit. --- Rich http://richlockyer.tripod.com/ >>>Dump the wetsuit and the 100lb dual bladder. Unless you're carrying >>>several steel stage bottles, you don't need more than 55 pounds of [quoted text clipped - 9 lines] > It is obvious how "overkill" these huge bladders are when you run the > numbers. You are right. 100lbs is overkill. But, he has the wing already. Why not use it instead of spending a couple hundred more? >> Absolutely. The Explorer 70 was made with European divers in mind who >> have a hard time getting Luxfer stages. [quoted text clipped - 3 lines] >You are right. 100lbs is overkill. But, he has the wing already. Why not > use it instead of spending a couple hundred more? Because it promotes dynamic instability. With the bungees removed, it may be difficult to properly/fully vent. With the bungees installed, a puncture at any point on the wing will result in it dumping. With a non-bungeed wing, a puncture only results in loss of capacity below the hole. You'd catch me in a stab jacket before you'd catch me with a 100-pound bungee wing. --- Rich http://richlockyer.tripod.com/ [...] > With the bungees installed, a puncture at any point on the wing will > result in it dumping. [...] Even though to bladders are back-to-back? Do you mean because the bungies fold the bladders together so that puncture damage can go through both Rich? >[...] >> With the bungees installed, a puncture at any point on the wing will [quoted text clipped - 3 lines] >Even though to bladders are back-to-back? Do you mean because the bungies >fold the bladders together so that puncture damage can go through both Rich? Just referring to bungee wings in general... not the specific problems of the dual bladder wing, but that does bring up a good point. If you hole your wing, how do you know that the backup bladder is sound? --- Rich http://richlockyer.tripod.com/ > You'd catch me in a stab jacket before you'd catch me with a 100-pound > bungee wing. There's a local wreck with a spare transmission gear hanging on the engine room wall. I've been wondering how the hell I could get it out of the engine room. Thanks for the assistance! >>>Absolutely. The Explorer 70 was made with European divers in mind who >>>have a hard time getting Luxfer stages. [quoted text clipped - 3 lines] >>You are right. 100lbs is overkill. But, he has the wing already. Why not >> use it instead of spending a couple hundred more? > Because it promotes dynamic instability. > With the bungees removed, it may be difficult to properly/fully vent. > With the bungees installed, a puncture at any point on the wing will > result in it dumping. > With a non-bungeed wing, a puncture only results in loss of capacity > below the hole. Those are a lot of maybe's. >> Because it promotes dynamic instability. >> With the bungees removed, it may be difficult to properly/fully vent. [quoted text clipped - 4 lines] > >Those are a lot of maybe's. Maybe's that I would prefer to not have to worry about. --- Rich http://richlockyer.tripod.com/ > contact > will roll the right post off, but roll the left post on. If a knob > breaks off due to contact, the left post will be on and the right will > be off. Hmmmmmm? ab > The main reason for this is related to cave/wreck, because contact > will roll the right post off, but roll the left post on. Ya got that backwards >> The main reason for this is related to cave/wreck, because contact >> will roll the right post off, but roll the left post on. > > Ya got that backwards Not if ya wear em valves down... >>> The main reason for this is related to cave/wreck, because contact >>> will roll the right post off, but roll the left post on. >> >> Ya got that backwards > > Not if ya wear em valves down... Why would rotating a tank around the axis of the valve change the direction in which the valve opens/closes? SignatureSteve The above can be construed as personal opinion in the absence of a reasonable belief that it was intended as a statement of fact. If you want a reply to reach me, remove the SPAMTRAP from the address. > Why would rotating a tank around the axis of the valve change the direction in which > the valve opens/closes? It wouldn't, but it would put the regs in a silly position (like being down isn't already silly enough). For valves down, you rotate the tanks around the axis of the valves and also around the perpendicular axis that runs through the isolator. > It wouldn't, but it would put the regs in a silly position (like being > down isn't already silly enough). For valves down, you rotate the tanks > around the axis of the valves and also around the perpendicular axis > that runs through the isolator. Never mind. I have to stop posting before coffee. >> Why would rotating a tank around the axis of the valve change the direction in which >> the valve opens/closes? [quoted text clipped - 3 lines] >around the axis of the valves and also around the perpendicular axis >that runs through the isolator. Still doesn't change what happens to the left post and right post... you've just reversed the left and right. --- Rich http://richlockyer.tripod.com/ > Still doesn't change what happens to the left post and right post... > you've just reversed the left and right. yup, realized it right after the first sip of coffee. >> Still doesn't change what happens to the left post and right post... >> you've just reversed the left and right. > > yup, realized it right after the first sip of coffee. Upside down, backwards, inside out, and it still works! Ain't scuba grand! >> The main reason for this is related to cave/wreck, because contact >> will roll the right post off, but roll the left post on. > >Ya got that backwards Oops. --- Rich http://richlockyer.tripod.com/ Um, wow. Great replies everyone. Thanks!! Will apply my own thinking to filter all these ideas (every diver does this right??). :) To answer a few questions... I'll be diving with DMs/instructors with 1,000s of dives with doubles. I'm not just jumping in the water with an extra tank on my back. :) (Yes, I realize this is a luxury that I can't depend on and that doesn't replace common sense.) My buddy on my first 10/20 dives will be one of the DMs. I live in Whitby, Ontario. An XL dry suit would be huge on me (5' 7"; 150 lbs). Thanks anyway. Again, thanks everyone. > Um, wow. Great replies everyone. Thanks!! > > Will apply my own thinking to filter all these ideas (every diver does this > right??). :) Right. |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.