Northwest Dive Club

Hey everyone, not sure if this is in the right forum or not so feel free to move it if need be.

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

I am guessing to do this dive safely I will need more air then that right?

j3rmzh wrote:Hey everyone, not sure if this is in the right forum or not so feel free to move it if need be.

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

I am guessing to do this dive safely I will need more air then that right?

It depends on what your air consumption is. Are you a newer diver?

Yeah, I have 44 dives under my belt last time I counted, so yes I am new.

I do ok with air consumption (at least I think), most of our dives lately have been in the 30-60fsw range and last around 45 minutes, my buddy has a higher SAC rate (thats what its called right?) and I usually end up with about 800-1000psi

j3rmzh wrote:Yeah, I have 44 dives under my belt last time I counted, so yes I am new.

I do ok with air consumption (at least I think), most of our dives lately have been in the 30-60fsw range and last around 45 minutes, my buddy has a higher SAC rate (thats what its called right?) and I usually end up with about 800-1000psi

You can probably do it but the question really is if most of your dives are in the 30 fsw - 60 fsw range are you ready to go to 100 fsw? You'll have to answer that.

Assuming (from the info provided) that your average depth is 33 fsw for 45 minutes and you have 1,000 psi left over then your SAC rate would be around .57 cu ft/min. If that holds true you should be able to go to the I-beams and leave at about 1,500 psi and you should be fine.

It's definitely been done so it's more a question of whether you are ready/comfortable at that depth.

Personally, I'd start doing more dives in the 60 fsw - 80 fsw range if you are comfortable with that and then think about going to the I-beams.

Yeah- one rule of thumb is to not dive deeper than the cubic feet of the tank you have- no deeper than 80' on an AL 80, for example. That said, people break that rule regularly. If you're going to try it, maybe you should agree with your buddy in advance to turn the dive when either one of you hits 2000 psi and head for shallower water- assuming you start w/ 3000 psi, of course- that way you use 1/3 there, 1/3 back, and 1/3 for emergencies.....but be carefull- it's really amazing how much faster your gas goes at depth- keep a close eye on your SPG.

Nailer99 wrote:Yeah- one rule of thumb is to not dive deeper than the cubic feet of the tank you have- no deeper than 80' on an AL 80, for example. That said, people break that rule regularly. If you're going to try it, maybe you should agree with your buddy in advance to turn the dive when either one of you hits 2000 psi and head for shallower water- assuming you start w/ 3000 psi, of course- that way you use 1/3 there, 1/3 back, and 1/3 for emergencies.....but be carefull- it's really amazing how much faster your gas goes at depth- keep a close eye on your SPG.

That's a new rule to me, but it makes a fair bit of sense. The other thing that goes really fast down there is no-deco time, so you need to watch that closely as well. We've been down to the I-beams and the log piles twice, and both times we found that we only had about 3 minutes of bottom time left without going into decompression, that according to our computers. Part of the reason for that is probably that we tend to do everything slowly, including making or way down there, so your mileage may vary greatly. Nevertheless, at 100 fsw, you eat up the NDL fast, so watch your air and watch your bottom time. And watch out for the narcosis factor, as well.

There's a rock pile just at the shallow end of the Ibeams which might make a nice "stepping stone" dive first. At high tide its 75ft at the shallow side and 85ft on the deep side. Just north (left) of the big loop of rope at the top of the Ibeams.

I would consider a hp100 or lp95 as a good tank for these dives. An AL80 is really too small IMO. Esp. considering your buddy's higher consumption. Also 32% nitrox is a good idea.

Lot of good advice here. You have your air planned, your careful, etc, etc. Then you see a 6 gill shark, WOW super cool. You look at your gauge and you have 300 lps. and your at 100 ft.

My advice is wear a Pony Bottle, enjoy the shark, etc, etc.

Never ever want to run out of air, plan for the worst. I wear a 100 cf tank plus a 19 cf pony. There is no such thing as too much air!!

Pat Harman

I'd say a 100 or 95 is a REALLY good idea for this dive. I've only been around the I-beams once ( I don't dive at cove 2 very much) But the advise that others are giving you is good. An al80 will get you there and back, as long as NOTHING goes wrong. A 119 or a 130 is better if you can get one.

As stated above, EAN 32 is not a bad idea either, going into deco without sufficient gas is a bad thing.

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

IMHO ppharman's 19 is at the very low end of what is useful as a pony. It'll get you up from 100fsw or so, but no deeper, and at the surface, it'll most likely be empty.

Glad to see you're asking the question though, that shows you're thinking about Gas Management, and that's a HUGE step in the right direction.

Jake

Nailer99 wrote:Yeah- one rule of thumb is to not dive deeper than the cubic feet of the tank you have- no deeper than 80' on an AL 80, for example.

Based on that rationale, you should stick to 19feet, or is it 38?

j3r - check out the thread in the gear section here: http://www.nwdiveclub.com/viewtopic.php?t=3896

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.

The rule of not going deeper in feet than you have cubic feet of gas in your tank is a REALLY GOOD ONE!!! Follow it.

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).

Remember... your buddy has a higher consumption rate so if he/she has a problem, you need more than TWICE the air YOU WOULD NEED in your tank to get the BOTH of you to the surface while sharing.

And generally, if you need to ask how much gas you require to go to the i-beams, you have no business going there. Get more dives under your belt, then hook up with a "big buddy" at one of the upcoming big-buddy dives, and it won't be long before someone can lend you a larger tank and you'll have the experience to go to the i-beams... with someone who is very experienced and who has been there before.

It's kind of like a Ferrari... "if you have to ask how much it costs, you can't afford it." Don't rush to buy a Ferrari before you know how to drive your Chevy like a pro.

See, I told you.

Sounder wrote:
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.

Agreed. We've been there twice, both times with our LP 95's, and both times I came away asking why we bothered. Take your time going to and around the Honey Bear wreck instead, it's a lot more fun.

There's nothing wrong with wanting to go to the I-Beams. Everyone has different ideas of what a good dive is...Salt Water State Park wouldn't be on my list...but it is important that one is able to safely get to and from whatever site they do choose.

gcbryan wrote:There's nothing wrong with wanting to go to the I-Beams. Everyone has different ideas of what a good dive is...Salt Water State Park wouldn't be on my list...but it is important that one is able to safely get to and from whatever site they do choose.

I totally agree, and no "awesome" dive is worth doing without sufficient training, equipment, and experience. I think you'll agree with me, however, that if they're asking about this, they're probably not ready for it.

Nwbrewer wrote: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!

As I found out when escorting a couple of visiting divers who were on air, if you take your time downslope and enjoy the critters, you'll arrive at the I-beams with almost no no-deco time left. So, entirely aside from the gas considerations (which are paramount, and much more important than deco), until you're diving Nitrox, it's hardly worth doing.

I highly recommend attending one of Bob's gas management seminars. It'll give you all the tools you need to answer this kind of question.

And, since nobody else has said it, kudos to you for thinking about these issues before haring off and doing the dive.

mattwave wrote:

Nailer99 wrote:Yeah- one rule of thumb is to not dive deeper than the cubic feet of the tank you have- no deeper than 80' on an AL 80, for example.

Based on that rationale, you should stick to 19feet, or is it 38?

We didn't cover that in my classes......should it be feet or meters? Anyway, I don't pay attention to depth, just scrubber life- once I hit 3 hours on that sucker, I grab my inflator and jam my thumb on the "up" button until I break the surface like a Navy sub in one of those recruiting pictures......

yeah, I am well aware that I am not quite ready to do something like this, the way I see it one of the best ways to learn (besides just time in the water) is asking.

THANKS for posting the question and thinking about it!

Helps lots of folks learn (you'd be surprised how many lurkers read these threads, learn and profit from them, but don't interact) and underlines you're on the right track yourself asking the right questions!

Sounder wrote: 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.

Have you seen calvin Tang dive on a Alumin. 80...? He can go 2 hrs on one of those tanks.. :hello2: I dont know how he does it..?

mattwave wrote:

Nailer99 wrote:Yeah- one rule of thumb is to not dive deeper than the cubic feet of the tank you have- no deeper than 80' on an AL 80, for example.

Based on that rationale, you should stick to 19feet, or is it 38?

Yeah, but he double dips so he counts it like 8 times. I'm not sure if that's cool or just gross. (kidding. it's definitely cool)

-Ben

My recommendation FWIW is to continue diving within your comfort Zone and improve on your skills with your current buddy. Plan on taking an Advanced class which will cover Deep diving, Navigation, Night/Low Vis, Search and recovery and more. If you take the right Advanced class you could get into some Gas Management calculations. Someone once recommended an Instructor to me for AOW and I'd be glad to recommend the same Instructor for you if/when you are interested in continuing your education. Perhaps you've heard of him.......Bob Bailey? Brian Wiederspan also covers GM in his AOW and perhaps some other instructors I'm not familiar with. If you just want information about GAS Management without an Advanced Certification then Bob's FREE Seminars are invaluable for people such as yourself who want to know the "Mystery" of how deep can I go and how much do I need. There is a lot more to it than do I have enough to get there and back.

I don't think Nitrox is necessarily a big issue here on an aluminum 80. If you have it great but no one is going to spend 20 minutes at the I-Beams with a tank that size.

I don't think anyone is going to slowly make their way downslope looking at critters on such a dive either. More than likely you would do a surface swim to the white buoy, drop down at 50-60 fsw and head directly to the deeper end of the I-Beams and do your critter watching as you come back up slope.

It's doable in a safe and conservative manner. You make your dive as short as you need to make it to be safe.

It sounds like the OP has gotten a lot of good info/advice here. I'd like to just point out that a dive like this with a little more experience can be safely done with an aluminum 80. Not having a lot of time at the I-Beams isn't necessarily a reason to not do it. It doesn't take a long time to see what the I-Beams have to offer.

I personally do my poking around for sealife on the way back upslope and try to get to the deepest part of the dive fairly quickly.Taking a Gas Management Seminar would be great. You'll see it's not necessarily about having a bigger tank or Nitrox. It's about safely planning a dive around what you do have.

Having said that, if you are average sized or larger you will eventually get a larger tank!