How much air to get to the cove 2 I-beams?

[Nwbrewer]

See, I told you.

Well, we've all got our "hot button" issues... gas planning is one of mine.

I do hate it that you predicted it so perfectly though... you must have written and posted that just as I was writing my post!

Personally I'm glad that you're around to jump on this stuff, it saves me from having to type out all the math. That's why I pointed to your Pony Size post, too lazy to do the typing myself.

Jake

[Grateful Diver]

First off ... kudos for asking the right question.

To many people get focused on how much air they'll have at the end of the dive, and neglect to consider how much they should have to begin it. That's how a lot of people get into trouble.

One thing to emphasize is that the whole purpose of diving with a buddy is to be able to help each other out if something goes south ... therefore you also need to consider how much air you and your buddy would need to surface safely from the I-beams if for some reason he lost the use of his air at the worst possible time.

And it does happen ... one of my former students had a free-flow just as we reached the top of the I-beams, and she had to go on her buddy's air supply and shut down hers to stop the free flow. Because we'd planned the dive properly, they were able to make a safe ascent on just one person's air.

One of the exercises I have my AOW students do is to calculate how much air they'd need to do a planned dive to the I-beams ... then after the dive calculate how much they actually used. It usually turns out that they decide for themselves that an AL80 isn't an appropriate size tank for the dive.

Keep in mind that as long as everything goes right, it will most likely be plenty of air ... but part of dive planning is to ask yourself how prepared you'd be if something went wrong. In this case, having enough to share with your buddy is what you have to plan for ...

... Bob (Grateful Diver)

[Grateful Diver]

If you insist on going to the I-beams, realize that when wearing an Al80 tank, you should be turning the dive and heading shallower when you hit 2300psi. That gives you 700psi to get to the I-beams, enjoy them, and get out... you'll be at the I-beams for 1-2 minutes at the rate you're describing you have (which is a fairly normal comsumption rate).

I don't know where you got 2300 but its alot more than I would reserve. Taking 3 min to get up from 100 to 50ft. Then 1min stops up from there (which is probably unrealistic for j3rmzh and his buddy). 8 min ascent. That schedule requires 40cf at a SAC of 1 (each). 1600psi rock bottom (or whatever you choose to call it).

With newer divers I see working SAC rates higher than 1 CF per minute routinely ... one of the people you dive with had a working SAC of more than 2 CF per minute when he took my AOW class. He's much ... MUCH ... better now, but you plan for what you have, not what you'll eventually obtain.

j3rmzh maybe you can wrangle up a big buddy to take you down there (or close like the rock piles) someday over the next few months.

Sure ... j3mzh, drop me a PM. If we can work out an appropriate time, I'll take you diving, and if it looks like you can handle it OK I'll take you down there ... and loan you a bigger tank to do the dive with. You can see for yourself how much air you use.

... Bob (Grateful Diver)

[Sounder]

If you insist on going to the I-beams, realize that when wearing an Al80 tank, you should be turning the dive and heading shallower when you hit 2300psi. That gives you 700psi to get to the I-beams, enjoy them, and get out... you'll be at the I-beams for 1-2 minutes at the rate you're describing you have (which is a fairly normal comsumption rate).

I don't know where you got 2300 but its alot more than I would reserve. Taking 3 min to get up from 100 to 50ft. Then 1min stops up from there (which is probably unrealistic for j3rmzh and his buddy). 8 min ascent. That schedule requires 40cf at a SAC of 1 (each). 1600psi rock bottom (or whatever you choose to call it).

But I would only be doing a dive like this in rare circumstances. Cove2 is not the time or the place for a 100ft dive on air in an AL80; esp. with <50 dives.

j3rmzh maybe you can wrangle up a big buddy to take you down there (or close like the rock piles) someday over the next few months.

You're right - too high. I don't know why I got my wires crossed from the pony thread and this one... tired I suppose. I think I was shooting for "worst case" scenerio not knowing consumption rates for him and his buddy... and I didn't feel like working out more math (I'm not speaking with my HP12c right now... it didn't behave properly during a Finance exam).

[CaptnJack]

With newer divers I see working SAC rates higher than 1 CF per minute routinely ... one of the people you dive with had a working SAC of more than 2 CF per minute when he took my AOW class. He's much ... MUCH ... better now, but you plan for what you have, not what you'll eventually obtain.

Sure some newer divers have SACs >1. But if j3rmzh doesn't know what his is (a warning sign) or has a SAC rate that high I don't think anywhere near Ibeams kinda depth is a good idea. Regardless of tank size. The beams aren't going anywhere and can be done 6 months from now.

[Sounder]

With newer divers I see working SAC rates higher than 1 CF per minute routinely ... one of the people you dive with had a working SAC of more than 2 CF per minute when he took my AOW class. He's much ... MUCH ... better now, but you plan for what you have, not what you'll eventually obtain.

Sure some newer divers have SACs >1. But if j3rmzh doesn't know what his is (a warning sign) or has a SAC rate that high I don't think anywhere near Ibeams kinda depth is a good idea. Regardless of tank size. The beams aren't going anywhere and can be done 6 months from now.

Yes, I agree - they'll still be there and in 6 months the pissed off lingcod will have calmed down a bit. Course, there's a REALLY aggressive lingcod around the bow of the honey bear right now!

[dwashbur]

With newer divers I see working SAC rates higher than 1 CF per minute routinely ... one of the people you dive with had a working SAC of more than 2 CF per minute when he took my AOW class. He's much ... MUCH ... better now, but you plan for what you have, not what you'll eventually obtain.

Sure some newer divers have SACs >1. But if j3rmzh doesn't know what his is (a warning sign) or has a SAC rate that high I don't think anywhere near Ibeams kinda depth is a good idea. Regardless of tank size. The beams aren't going anywhere and can be done 6 months from now.

Yes, I agree - they'll still be there and in 6 months the pissed off lingcod will have calmed down a bit. Course, there's a REALLY aggressive lingcod around the bow of the honey bear right now!

Is that the one in the den underneath is with the gigantimous teeth? We gave that one a wiiiiiiiiiiiiiiiiiiiiide path............

[Sounder]

I'm not positive whether this is the one you're talking about or not, but this one came out to meet us in mid-water and was quite aggressive... and he found out how my turtle fin tasted.

[hoover]

Honestly, with 44 dives you shouldn't be going to the I-beams. They'll still be there when you have more experience, and to be quite frank... they're not that great anyway.

that's an interesting statement. just pondering that since i have gone to the i beams more than anywhere else and I am a new diver... i would say probably 8 out of my 40 dives, usually at night. but that said, if I am going to the ibeams, that is where i am going...so i don't waste gas getting there. sometimes do surface swim and try to do direct descent which usually gets me close if I line it up right. if I am going to the ibeams, dive a HP100 or HP120 with a 19 cf pony.

i like the ibeams at night because they are much more surreal...maybe b/c i am still hoping to spot that 6 gill too.

but i guess sounder's point about if you have to ask about how much gas...you probably shouldn't be diving to 98' yet makes a lot of sense.

wait...who am i to offer advice...i just pointed out I only have 40 dives! :)

[Grateful Diver]

that's an interesting statement. just pondering that since i have gone to the i beams more than anywhere else and I am a new diver... i would say probably 8 out of my 40 dives, usually at night. but that said, if I am going to the ibeams, that is where i am going...so i don't waste gas getting there. sometimes do surface swim and try to do direct descent which usually gets me close if I line it up right. if I am going to the ibeams, dive a HP100 or HP120 with a 19 cf pony.

i like the ibeams at night because they are much more surreal...maybe b/c i am still hoping to spot that 6 gill too.

but i guess sounder's point about if you have to ask about how much gas...you probably shouldn't be diving to 98' yet makes a lot of sense.

wait...who am i to offer advice...i just pointed out I only have 40 dives!

Most of us did dives when we were new divers that ... in hindsight ... we probably shouldn't have done. There's a saying in diving ... "you don't know what you don't know" ... and hindsight always provides a clearer view.

On the other hand, we all want each other to be safe ... and it's often the case that newer divers don't understand that you're safe as long as nothing goes wrong during the dive ... but you might not be if you had to for some reason have to deal with an emergency situation. It's always prudent when planning a dive to consider what might go wrong during the dive, and what you would do about it if it did.

Running out of gas is only one of the potential problems a new diver might be faced with ... ask yourself what would happen if you or your dive buddy suddenly had a free-flow and had to make a direct ascent on one diver's gas? Have you ever had to make an ascent from that depth without having the use of any visual aids? It's not that difficult, really, if you've practiced it a few times ... but losing your visual references can be very disorienting for someone who's doing it for the first few times.

When planning a dive, always consider what could go wrong, what you'd do about it if it did, and be honest with yourself about your ability to handle the emergency. Most of us think we're better at these things than we actually are ... so it's always a good idea to test your theory in shallow water once in a while just to make sure you can really do what you think you can ...

... Bob (Grateful Diver)

[RSdancey]

I am interested in checking out the I-beams out at cove-2 but all I have right now are single aluminum 80's

In general, I think the 60-100fsw dives off Cove 2 are a fantastic training ground for dives all over the Puget Sound. They should not be attempted without the right training, the right gear, and the right planning.

I assume you have an Advanced Open Water certification. Since you've done 40+ dives, I'd say you're likely reasonably experienced with the basic process of diving safely. You're certainly experienced enough to be talking about diving to the I-Beams.

The beauty of the Cove 2 diving environment is the slope. Unlike a lot of "deeper" dives, you're not going to be jumping off into an abyss and dropping to max depth (for example, a standard boat dive at KVI towers...) Instead, you're going to be descending a very stable, easy to navigate slope. Depending on where you dive, that slope may have a lot of landmarks or be a featureless plane of dirt (although after you dive it often you start to recognize landmarks even in the dirt!) If you become uncomfortable, you've got an easy, visual reference to help get to safe depth - just swim up the slope.

The slope itself is a nearly ideal ascent profile as well. If you proceed up the slope at a reasonable, slow swimming rate, you'll usually stay well below 30ft/second.

There are also lots of incremental milestones to use. You don't have to just jump in and swim down to the I-Beams, but you can take several interim steps over several dives to gain confidence.

Here's my advice: Dive down the boundary line from Cove 2 to start. It is well marked, and because parts are elevated with floats, you can usually find it even when there's lots of seaweed. REMEMBER: Stay on the south side of the line, out of the Ferry zone. Swimming down the slope you should always have the line on your left side.

You will find many interesting features along the line down the slope - concrete blocks, metal debris, and logs.

Do a dive down to 60fsw to reconnoiter the line & get familiar with the process of descending and ascending in Cove 2. There may be other divers, some with really bright lights, and scooters. There may be seals. There may be a lot of algae/dirt/crud in the water that reduces visibility. There may be jellyfish (and some are real stingers!) Cove 2 is a busy, busy place to dive. Be sure you can ID your buddy, and your buddy can ID you, even under some tough visibility conditions.

On your next trip, go perhaps down to 80fsw. Monitor your consumption rates. Get used to how dark it is down there - be sure you bring good lights. Make slow, safe ascents. Make sure you do safety stops; 3 minutes at 15fsw minimum, or something even more conservative (I like to do 1 minute stops every 5 feet from 30 feet on up).

On your third trip, go down to the 80+ fsw areas. Don't go deeper than you AND your buddy are comfortable diving. Make sure you make slow, safe ascents! After you've done this kind of a dive, take stock. Were you OK? (It is more than alright to be frightened/uncomfortable. It is an unnatural place to be, under unnatural conditions. It takes A LOT of getting used to. But fear is manageable. If you were feeling panicky, or did panic, felt vertigo, claustrophobia, or just "fear of the deep" that made you very unhappy, you probably need to do these starter dives several more times (or you need to decide diving this deep in Puget Sound isn't for you, which is a completely reasonable reaction.)

If you're feeling comfortable, and your buddy is feeling comfortable, you're probably ready to take your first trip to the I-Beams. Ideally, go with a guide, someone who knows how to get there. It's not complicated, but there is a bit of navigation required.

Also, just know that diving below 60fsw means short dives. You're not going to be setting any duration records, especially not with AL80s. These are really going to be "take a look, come home" dives.

BEFORE YOU DO THESE DIVES, get some advice about gas planning. You need to understand how to make a safe gas plan. GD's course is ideal. At the bare minimum, spend some time reading about "Rock Bottom". Divers have died on the boundary line. It is a safe dive, when done safely, but those depths are no kidding serious and you owe it to yourself, and your buddy, to understand what kind of gas you need to be carrying to dive this safely.

I was at about 40 dives when I realized my training had been inadequate to provide a safety margin I was comfortable with, and that my buoyancy & trim skills needed a lot of work. Diving the I-Beams may raise some of those issues with you and your buddy as well. Just know that there are people who dive the Puget Sound regularly who are willing & able to help get you past that point, if you ask. We all want more safe diving friends, and nobody wants to read about sad stories at Alki.

RyanD

[hoover]

Most of us did dives when we were new divers that ... in hindsight ... we probably shouldn't have done. There's a saying in diving ... "you don't know what you don't know" ... and hindsight always provides a clearer view.

I guess one more piece of qualification here. I should mention that most of the time I dive with buddies that are more experienced (by far) than me. If I am taking out less experienced people, I DO NOT go to the IBeams. Think the deepest dive that I have led with less experienced divers was to 70' and one of the AOW divers that was there started getting stressed so we came up shallower.

It is hard to find dive buddies that have the inexperience I have, yet have all their gear and want to do interesting dives. SAC rate is also a limiter...so I end up diving with divemaster friends, instructors, and other people that have hundreds or thousands of dives.

I always think about rescue, just finished a rescue course too. But I guess I don't have to worry about it as much when I am the least experienced diver in the group...yet personally prepared to self rescue if I need to.

Free water descents and ascents are really fun, I know what you mean about the ascent being hard and it probably is something I should practice more. usually i use a surface marker on my reel for safety stops in free water (just makes "hanging" at 15' that much easier)...but that doesn't mean the rest of the ascent is easy... i did get lots of practice doing ascents with a buddy that was playing unconscious laying on the bottom during rescue.

Anyway, guess I am rambling now. I just wanted to qualify my dives a bit more since the people I dive with are more experienced than I am. Totally agree with your points Bob, thanks.

:)

[Pez7378]

Dive with Bob. You'll learn more than you thought you could.

[Sounder]

Dive with Bob. You'll learn more than you thought you could.

Heck, Pez is a great guy to jump in and learn from! There are MANY people here who dive regularly and are happy to help out... there is just simply no need to make a dive, like a jaunt to the I-beams, for the first time without someone much more experienced to lead and be there with you.

Warning: Soapbox post ahead: (Sounder climbs up on his soapbox, clears his throat, and...)

In my opinion (and, of course, opinions are like ), I would recommend trying to do "learning dives" with someone who has at least 200 dives. Better yet, look for people who are counting dives in the thousands. Like Ryan, at 40 dives I wasn't nearly as confident in the water as I wanted to be. Through hard work, 2 amazing mentors, and TONS of diving, I've started to turn the corner - I'm just starting to become the diver I want to be but I have A LOT more to learn and improve upon. I'm only now starting to learn what I don't know... and what I didn't know (yeah, at less than dive #25 I was at 94fsw in Maui, on an Al80 with air...dumb, dumb, dumb ](*,) ).

I'd also like to point out (I mean no disrespect here) that while an ascent with an unconcious diver is an excellent skill, and very important to be included in a well-rounded rescue class, the ascent done in the class is far different than a free ascent from the I-beams. When there are no visual references above, below, or around you, the ascent becomes much more difficult. Then you add stops, buddy awareness, navigation (yes, you may need to be navigating somewhere while you're mid-water with no visual references while maintaining depth and keeping track of your buddy), discomfort/panic (we don't usually choose to make free mid-water ascents outside of training unless something went wrong), and the potential of whatever issue caused the need for the free ascent, and you're talking about a situation that can turn bad in any number of ways.

I don't know that I, personally, wouldn't call free mid-water ascents "fun" per say (but, to each their own), but when practicing them with my regular buddies, it feels good to know we've "been there before" should the situation ever call for one...

This couldn't have been more true for several experienced members of this board when they were at the I-beams and someone had an out-of-control free flowing regulator. Because of their experience (two of the divers counting their dives in the thousands and the other two counting dives in the mid-hundreds), training, and on-going practice (including the skills necessary to manage this issue), the situation was managed beautifully with a perfect OOG sharing, tank shut-down, and mid-water ascent with stops from about 98fsw to the surface.

I apologize for preaching... I should leave that to the pastors among us. I'm just troubled by what I "didn't know that I didn't know" when I was a new diver (I consider "new" as having less than 200 dives) and am troubled when I hear of someone becoming injured or dying after having made stupid mistakes that experienced divers would have advised against. If I stand on my soapbox and someone benefits, then I can feel alright when something unfortunate happens knowing I tried.

Mattwave shared something with me that really sums it up... "when you're diving, you have to realize that you're only 1 breath away from death." Please be safe out there, and I am so happy that this question was posted. In my opinion, this is the BEST use of forums like these. It's also great to have a thread like this continue without a "moderation cluster-f" blowing up.


Oh yeah, and one more thing... I love Mack & Jacks.

[dwashbur]

While I don't necessarily agree with the 200 figure (since I only have about 120 and am close to being an instructor I can echo everything else Sounder said. If safety isn't the paramount factor in what you're doing, stay out of the water for today and try again tomorrow with somebody who's been there. As I keep telling students when they can't clear their ears, let it go for now, and live to dive another day (with apologies to James Bond )

[lamont]

my first time down to the i-beams was on dive #7 with an Al80. not fantastically intelligent... my turn pressure was a pretty conservative 1800 psi and we didn't do more than touch+go off the near end of the i-beams and then headed for shallower depths. not enough time to get wiggy from the narcosis either. plus i had two divers in doubles and long hoses flanking me...

i don't recommend that.

however, by dive #50 i'd think i'd taken Nav, Deep, Rescue, Nitrox and Fundies and had 130 cu ft tanks and was getting 20-30 mins of bottom time at 90-100 fsw.

50 dives and going to the i-beams seems reasonable to me. the boundary cable ups the ante a bit. i had one dive where we were trying to go to the olive's den, got narc'd and went half way around the boundary cable before realizing our error and turned it and surfaced a little wigged out from our dive plan having gone sideways. definitely appreciated having HP steel tanks on that dive and it was probably dive #75.

went back around the boundary cable around dive #150 on doubles and it was just no BFD... seemed to be over really quick...

and gotta give pr0pz to bob, too...

helps if your buddies tend to throw random OOAs on you and you do skills dives to make sure you know how to donate gas, know how to calculate gas reserves, have good buoyancy control, know how to make a free ascent without a reference without shooting uncontrolled to the surface, etc...

[Sounder]

helps if your buddies tend to throw random OOAs on you and you do skills dives to make sure you know how to donate gas, know how to calculate gas reserves, have good buoyancy control, know how to make a free ascent without a reference without shooting uncontrolled to the surface, etc...

This is paramount to being a strong diver and I feel VERY fortunate to have buddies who are willing to train and practice these kind of things with me... on almost every dive.

[lamont]

On your third trip, go down to the 80+ fsw areas. Don't go deeper than you AND your buddy are comfortable diving. Make sure you make slow, safe ascents! After you've done this kind of a dive, take stock. Were you OK? (It is more than alright to be frightened/uncomfortable. It is an unnatural place to be, under unnatural conditions. It takes A LOT of getting used to. But fear is manageable. If you were feeling panicky, or did panic, felt vertigo, claustrophobia, or just "fear of the deep" that made you very unhappy, you probably need to do these starter dives several more times (or you need to decide diving this deep in Puget Sound isn't for you, which is a completely reasonable reaction.)

For at least my first 20 dives to the I-beams I averaged about an 80% incidence of paranoid narcosis. I didn't know what it was initially, i just had this feeling in the back of my head that something could go wrong. What I noticed was that as soon as I got above about 80 fsw it completely went away. I'd turn the dive at the I-beams swim back up to 80 fsw and it evaporated. Now, being a fairly rational person I knew that there was very little at 90 fsw out on the I-beams that could hurt me which could not also hurt me at 80 fsw. We also weren't very close at that point to the dive being 'over' and I didn't feel any sense of 'relief' that we were leaving depth, so that wasn't it. Eventually, I managed to correlate it with the fact that my short term memory also started dropping out deeper than 80 fsw (i.e. i was checking my pressure gauge and then completely forgetting the number and checking it again). After awhile I realized that it was due to narcosis, made worse by feeling cold, and made worse by poor breathing rates and CO2 buildup. By relaxing I got comfortable, did not build up CO2, had a clearer head and didn't get the wiggy thoughts down at the I-beams.

Then I started doing more dives around Olive's den and the paranoid narcosis started all over again. Which was annoying because Olive's den was only about 10 fsw deeper than the I-beams, but while I had become comfortable diving to the I-beams, I hadn't really gotten comfortable diving to 100 fsw in general. So after another 20 dives or so down to the Olive's den that started to resolve.

So the moral is to go slowly and pay attention to what is going on inside your skull. Build up experience gradually. Get comfortable and try to figure out how feeling relaxed at depth with good breathing leads to a much clearer head.

And be careful about skip breathing. Occasionally I'll get my SAC down to 0.30 cu ft / min while scootering on 30/30 (when I'm in better shape) and I'll get a touch of paranoid narcosis. As soon as the wiggy thoughts start, I know that I actually need to start breathing *more* to clean out the CO2...

So, relax your breathing rate, but not too much... You need to be exhaling enough to get rid of the CO2...

[lamont]

Also here's my rockbottom page:

http://www.scriptkiddie.org/diving/rockbottom.html

It might be better to work up to that though by looking at Bob's slides for his rock bottom class (i don't know where a url for those are though) -- bob is a *much* better educator and technical writer -- i tend to write documents more for myself than an audience...

[LCF]

So the moral is to go slowly and pay attention to what is going on inside your skull.

Man, this is SO true. My first couple of dives to the I-beams and to Olive's Den were marked by some really severe paranoid narcosis, to the point of hallucinating. The other day, Sounder and I swam the boundary line from Cove 3 to Cove 2, and I knew I was a little fuzzy, but no paranoia. I think it's a combination of just generally being far more comfortable in the dark and limited viz, diving doubles and not worrying about gas supply, and having a better breathing pattern to avoid excess CO2.

I'm still narced, I'm just not as out of control with it.

Those depths are better on helium, though.

[Sounder]

The other day, Sounder and I swam the boundary line from Cove 3 to Cove 2, and I knew I was a little fuzzy, but no paranoia. I think it's a combination of just generally being far more comfortable in the dark and limited viz, diving doubles and not worrying about gas supply, and having a better breathing pattern to avoid excess CO2.

...and here I thought you were so comfortable because of your awesome buddy!

[LCF]

Well, that helps!

[al NDOF]

I'm guessing Sounder will find this thread eventually and recommend one of Bob's Gas management classes, but in case he doesn't, see this recent thread on ponies. The math for a rock bottom number is important.

http://www.nwdiveclub.com/viewtopic.php?t=3896

Jake

thx for the link, very good information. I plan on taking Bob GMC soon; until then..

thanks for posting

[Sounder]

Also here's my rockbottom page:

http://www.scriptkiddie.org/diving/rockbottom.html

It might be better to work up to that though by looking at Bob's slides for his rock bottom class (i don't know where a url for those are though) -- bob is a *much* better educator and technical writer -- i tend to write documents more for myself than an audience...

Here is Lamont's write-up on calculating rock bottom too... also an excellent read. Between Lamont's notes here, and Bob or BDub's class, you'll be ready... but only if you practice it. Incorporating it into your dive planning will change the way you approach safe diving and will keep you sharp on your calculations.

[Benoit]

I am a new diver who decided to do AOW after doing only a few dives. I happen to go to the I-beams for my deep dive on an AL80, and recorded my air usage and depth on this dive. (My 9th dive).

My SAC is about 0.75 cf/min currently. I'm still getting used to using a drysuit and I was still wasting a lot of air fiddling with it (I have ankle vents). Anyway, using an AL80 and wanting a low ascent with stops, it pretty much meant spending very little time there. We pretty much just descended, did a few exercises there, and came back to 60fsw, then 30fsw, then finished the dive roaming around 15-25 for a little while to explore. We could probably have stayed a few more minutes at 100, but not many.

Here was my air usage and ND time along the way. (left side is "ft" or "cf", right side is minutes)



I was very surprised to see how dark it is there. I'm glad we both had lights, and I'm glad I was diving with an experienced instructor... I definitely wouldn't do this with an inexperienced buddy, and next time I go that deep I will definitely use an HP100+...