My (probable) conversion and a wing question

[BigJoshCRNA]

Ok...so I am sold on DIR. I have read Jablonski's book and it sounds like a great holistic approach to diving. So sold, that I have committed myself to the gym so that I can get into shape and am now looking to replace a lot of the equipment that I just spent soooo much money on. I have been in contact with GUE and though I don't see myself ever making penetration into caves or ships, but instead traveling the world diving recreationally and taking amateur pictures and videos, I am hoping to attend a fundamentals class in the next several months. (Anybody recommend a class in a warm location??? I don't want to have to buy a drysuit as well just so i can attend a class in florida/new jersey/california!!).

I met a DM in Cozumel that I really liked and trusted and will be diving again with him after I get back from Egypt, but all he uses are steel 120 tanks for the men.

So here is my question: Can I use a steel 120 tank with the 30lb wing?

I was told by someone who works at a shop that does the GUE classes that I need to get 25-50 dives with my new gear before I take the fundamentals class, but I want to make sure and buy the correct size wing. I know halcyon makes a 40lb wing and so far air consumption has been my limiting factor on all my dives...and yeah I have heard if I master that, I wont need a steel 120. And I don't know any other DIR divers to help mentor me in this area. (other than this site) Thanks! Sorry if I rambled!

 

[Gombessa]

For the vast majority of people, a 30lb wing should be sufficient to float just about anything you're likely to dive in the tropics (both in terms of keeping you afloat at the beginning of the dive, and floating your rig without you)

But you should pay attention to how such a big steel tank affects your weighting. A typical HP120 is about -10lb full and neutral when empty. Are you going to be wearing any exposure protection in Coz? If not, and depending on what kind of plate/hardware you get, you're potentially going to be anywhere from 15 to 20lb negative at the beginning of the dive. Can you swim that up if your wing fails catastrophically? (15lb is a lot to be able to keep up for one minute, and I can't do 20).

At the end of the dive, you'll be up to 10lb lighter due to using up the gas in your tank - that'll make you 5 to 10lb negative without any exposure protection - can you hold a stop for 3 minutes at 10-20ft with no air in the wing and without kicking yourself upwards? Can you stay on the surface while 5-10lb negative at the end of the dive?

These numbers seem to get more reasonable if you wear even minimal exposure protection, but for recreational dives in the tropics, it's much easier for me just to dive aluminum tanks, which my steel backplate offsets completely (and then some).

 

[BigJoshCRNA]

thank you Gombessa...

this is exactly the reason I need more friends with a technical understanding of diving...not just the casual "I dive twice a year" kinda folks...so here is my next question:

Your calculations are figured with me having no other weight other than the tank and the backplate? So, if I add any additional weight...which I have...14lbs with a 1mm wetsuit...I add a considerable amount to the force against I have to swim against in case of a total wing failure?

Second, How do I test myself to see how much I can safely swim up?...I assume it would mean that I take a full tank and weights to a reasonable depth and without any air in the wing, just try to swim it up and stay at the surface?

Third, my wetsuit will help compensate for extra weight at the surface, but not at depth, correct?

All in all though, I should follow the book and dive with weights/tanks that allow me to stay within that 30lb rule...correct?


Thank you so much!

 

[Gombessa]

Your calculations are figured with me having no other weight other than the tank and the backplate? So, if I add any additional weight...which I have...14lbs with a 1mm wetsuit...I add a considerable amount to the force against I have to swim against in case of a total wing failure?

My numbers are rough. I figure your full tanks are -10, a steel backplate and harness are -7, your regs are -2 or so, and if you dive with an unweighted STA, that's up to another 2lb. OTOH, an aluminum or kydex backplate on the other hand, with no STA and light components could potentially make this as little as -5lb, so that's the general 5-10lb range in addition to the tank.

Are you currently diving a backplate, and if so, what kind? 14lb of extra lead on a belt is probably overweighted, but it depends. Some people are more buoyant than others, some heavyset people need a lot of neoprene which makes them more buoyant as well, and if you're diving a jacket BC, that's up to 4lb of extra buoyancy to displace as well. On top of that, an aluminum tank typically needs 4lb more ballast than an average steel tank. So it all depends on the details. But yes, a weight belt would add to what you need to swim up unless you ditch it. If for some reason you had 14lb on a belt in addition to an AL backplate and HP120, you're talking about roughly 29lb to offset at depth at the beginning of the dive, which would pretty much require you to drop your weights and kick vigorously if you had a wing failure at the bottom.

Second, How do I test myself to see how much I can safely swim up?...I assume it would mean that I take a full tank and weights to a reasonable depth and without any air in the wing, just try to swim it up and stay at the surface?

Yep, you can do it in 6 feet of water; with your regular setup and a full tank, deflate your wing completely and try to keep your head above water for at least a minute. It should be a easier with a wetsuit on. You can then take off your belt and hand it to your buddy see how that affects things too. Make sure you have a buddy in the water with you, and don't forget you can just inflate your wing if you start getting winded. If you do this in a pool you'll have to account for the fact that fresh water is less dense than seawater, so you need to use less weight.

Third, my wetsuit will help compensate for extra weight at the surface, but not at depth, correct?

Exactly, if you go deep enough you can lose most of the buoyancy of your suit...for planning purposes, it's not atypical to assume a wetsuit has 0 buoyancy at depth, since it gives you a worst-case scenario. I don't think you get much buoyancy out of a 1mm suit though, maybe 3lb? I'm a wimp when it comes to cold so I always dive at least a 3mm.

All in all though, I should follow the book and dive with weights/tanks that allow me to stay within that 30lb rule...correct?

Not really, the capacity of the wing doesn't tell you if your weighting is balanced, it just lets you know the upper bound of what it will float. You'll notice that the proper weighting calculations typically assume an empty/busted wing:

• Your wing fails at the surface at the beginning of your dive - can you stay above the water long enough to ditch your weights? Do you need ditchable weight? Can you stay above the water once your weights are ditched?
• Your wing fails at depth at the beginning of the dive, can you swim it up? Can you ditch weights and swim it up?
• Can you hold a 10ft stop with a near empty tank and no gas in your wing?

What the wing capacity needs to do is keep you above water at your heaviest point (the beginning of the dive) and float your rig at the surface without you wearing it. I guess it also needs to maintain neutral buoyancy at max depth, as in the grossly-overweighted 29lb scenario, but if you're properly weighted none of these will be a problem. Generally, you want to be selecting a wing capacity based on your proper weighting, not weighting yourself based on the capacity of a particular wing.

 

[nadwidny]

...14lbs with a 1mm wetsuit...I add a considerable amount to the force against I have to swim against in case of a total wing failure?

To start with that sounds like way too much weight.

To answer the original question, can you use a 30lb wing with a steel tank? Answer, yes.

 

[TSandM]

Agree -- 14 lbs with a 1 mm wetsuit is a LOT.

BTW, you can take Fundies from resident GUE instructors in Bonaire or Grand Cayman, or in Mexico (although it's ridiculously expensive there), or in the Red Sea, Singapore, or a variety of other Asian destinations. And the system works beautifully for single tank, warm water recreational diving, too -- a fair bit of my diving has been exactly that!

 

[lamont]

14lbs with a 1mm wetsuit...I add a considerable amount to the force against I have to swim against in case of a total wing failure?

If your current BC traps gas and/or is just inherently buoyant, you'll probably lose some of that weight that you think you need by switching to a backplate/wing and learning how to completely dump it.

 

[danvolker]

Ok...so I am sold on DIR. I have read Jablonski's book and it sounds like a great holistic approach to diving. .

So here is my question: Can I use a steel 120 tank with the 30lb wing?

[\QUOTE]

BigJosh,
The 120 is a really bad mistake. It will create way to many problems ( bouyancy/weighting/drag, etc).

This is a tank usually sold by dive shops looking to make a quick buck on new divers with poor air consumption issues. The right advice by the right dive shop, would be to fix the heavy breathing issue, and settle on the aluminum 80 tank for typical dives at tropical locations.
Regards,
Dan V

 

[rjack321]

In a 1mm suit with a steel plate and a (smaller) steel tank (like an hp80 or 100 if that's what was available) I would use no lead.

With an aluminum plate and AL80 tank (preferred) I would probably use 3 or 4 lbs. About 8lbs if I was in a 3mm suit with vest (also preferred since I get cold easy).

As Dan suggests, I would not use a hp120 in the tropics. I would do more shallow dives where your greater air consumption isn't that big of a factor (<40ft) rather than massively upsizing your tank. In time and with practice you will relax and the consumption will come down.

14lbs with steel plate and a steel tank and barely any suit at all is rediculous. If you have that much adipose tissue you probably shouldn't be diving until you lose alot of it.

 

[BigJoshCRNA]

If you have that much adipose tissue you probably shouldn't be diving until you lose alot of it.

So...fat people shouldn't dive? I may never get in the water again...ugh! I have always been a big man and though overweight, I am not some huge fat slob. However, I may never be a guy with and 11% body fat.

I appreciate all the input guys. So far I have been diving a ScubaPro Knighthawk BC and am ditching that to buy the Halcyon with the steel backplate and 30lb wing. I am going to get a couple of dives in this setup before i take it to Egypt in a couple of weeks. Also, I found a GUE fundies class in Bonaire and will probably try to shoot for that in December. So, once again...thanks for the input...I have a lot of work to do and will be updating frequently!