Going Deeper than 130'

[MXGratefulDiver]

I have some questions about going deeper than 130'. I really have no desire to get into advanced tech diving for it's own sake, but I do want to get to around 160' or so. I live in Michigan and there are some things in Lake Huron that I want to see one day. I am a PADI Divemaster and I work mostly with Scout groups. I did this because I felt it was a great way to dive a lot and keep the costs down but I'm not a Divemaster for a living. I'd like to learn some more and do more wreck diving and to that end I'd like some advice on which way to go. I want to keep costs down of course, but I won't cut corners on safety. I'm a little turned off on DIR right now but I could be convinced--not a slam on DIR just what I read--I don't know enough to have a real opinion.

What is the minimum/recomended level of training and equipment needed to get to 160'? And where would you go for training? I know the question is a little lame, I'm not a minimum prep guy. The goal of my post right now is only to get enough information so I can start asking better questions.

I dive wet right now with no real problems. It's cold but not stressful for me. I suspect one day I may need to go dry, but not before I have to and I still have to get some time deeper than My current floor of 110 before I make that decision. On that note I've got 6 or so dives to 100+ with no concerns for narcosis... yet.
I currently use an AL80 but I'm likely going to a steel 120 this winter.
I won't be going solo.

Minimum level of training recommended ... Advanced Nitrox/Deco Procedures. These are planned decompression dives ... so learn a little bit about how to do those dives before attempting it. Once you get into the realm of decompression diving, much that you learned as a recreational level diver won't apply ... particularly in terms of how you plan and execute your dive ... because you no longer have a safe option of a direct ascent to the surface. This will also impact both the equipment and skill level needed to do these dives safely.

DIR doesn't have to be your thing ... TDI and NAUI offer classes sufficient to train a diver to properly dive to these depths. I'm sure other agencies do as well, but these are the ones I'm familiar with.

I also recommend some level of helium training ... trimix, heliox or heliair ... due to the effects of narcosis. You indicated you're planning to do these dives in Lake Huron ... cold water increases the effects of narcosis, and if I'm not mistaken the temps at depth in the Great Lakes is typically in the upper 40's pretty much year round.

Which also means getting a drysuit. Wetsuits are completely inappropriate for deep diving in cold water, due to compression. If you think 100 feet is cold in your wetsuit, wait'll you see what happens when you take it down another 2 ATA's ... you'll freeze your butt off. Now consider what your body does when it's cold ... it shunts blood away from your extremities and moves it into your core to protect your vital organs. Cold reduces your mobility and increases the risk of decompression sickness. You really don't want to go there. For the dives you're describing I'd say a drysuit is pretty much mandatory if you're planning to do them properly and safely.

Equipment ... if you're going to 160 feet in cold water, doubles is a really, really good idea. It's not just that you need sufficient gas ... you need redundancy as well. For 160 feet I wouldn't consider anything smaller than steel 100's ... although some folks will tell you that steel '85's would suffice. I think that really depends on your gas consumption rate ... as well as that of your buddy. Gas management at those depths is increasingly important, so you need adequate reserves to get both you and your buddy up from depth safely. If you're planning to carry deco bottles, you only need adequate reserves to get you to deco depths ... although a prudent diver also considers carrying enough to do their deco if, for any reason, they lose access to one buddy's deco bottle.

Above all else, don't take a dive like that lightly. It's not a recreational dive. Perhaps in warmer water you might get away with approaching it like a recreational dive ... but in cold water that's cutting your safety factors a bit thin.

Frankly ... and bottom line ... if finances are an issue, I'd say don't do it. Skimping on things like equipment and training for going beyond recreational depths is a great way to end up dead ... and your life is worth way more than the price of a couple classes and a set of doubles.

Just my 2 psi ... take it for whatever your think it's worth ...

... Bob (Grateful Diver)

 

[PfcAJ]

Just a quick look at Buhlmann (20/85) and VPM (+2) shows anything past about 6 or 7 mins as exceeding Minimum Deco. So ya, I'd go ahead and call a 160ft dive a deco dive unless you're playing bottom tag.

Buckaltc, you'll enjoy your dives to those wrecks a lot more if you take the time to get the right training and the right equipment for the dives. There's no rush (they aren't going anywhere, they're sunk). A 160ft dive can be a fun time, or the worst day ever. Proper training and equipment can make it the former and prevent the latter.

You said you're a little adverse to the whole DIR thing, but regardless of where you chose to go in diving, a GUE Fundamentals class can set a solid framework for your future. You'll learn about gas management, refine your trim and buoyancy, and polish some emergency procedures, as well as learn about team diving. Its really a great class.

 

[MXGratefulDiver]

160' is a decompression dive?

It depends on what table you are using.

Just curious ... what table says it's not? And how much time does it give you at 160 ffw?

... Bob (Grateful Diver)

 

[buckaltc]

Thanks everyone--I'm reading, keep em coming!

There is a lot I hadn't considered. I guess there is not question I need to go dry at some point. And maybe take an "intro" course to get more guidence.

 

[Superlyte27]

you'll poke your eye out kid...

 

[buckaltc]

One other note on cost to dive--l'll spend the money to go safe, or I'll skip the trip. The advice on gear is great so I don't waste any on gear I won't use. For example I'm thinking now of a steel 100 instead of the 120, so I can make a pair later since it looks like doubles are in my future. The point of the 120 was to cut down on tank changes between groups of students at the quarry. I'm also beginning to realize I'm going to need to go to a wing aren't I?

 

[MXGratefulDiver]

I'm also beginning to realize I'm going to need to go to a wing aren't I?

Highly recommended ... although there are BCDs out there that claim to be suitable for doubles, they are a compromise solution and will ultimately end up costing you more in the long run than just doing it properly in the first place. A good BP/wing setup is the most appropriate way to backmount doubles ...

... Bob (Grateful Diver)

 

[muddiver]

Just curious ... what table says it's not? And how much time does it give you at 160 ffw?

... Bob (Grateful Diver)

U.S. Navy No-D Table, Revision 6, 2008.

"160 fsw No-Stop Limit 5 Min, 3 Min dive = B RGD, 5 Min = C RGD" I assume that 160 ffw equates to approx 155 fsw which falls in the 160' section of the table.

Actual bottom time: your guess is as good as mine. Probably an "Ooo I touched the bottom, gotta go!" Because travel time down is approx 2 Min.

Now,

If the point that is being made is that this depth of dive is 1. Outside the limits of recommended recreational diving (past 130") 2. Not a dive for an inexperienced diver. 3. Requires some serious gas planning.

Than yes I agree with what is being posted.

 

[rongoodman]

As for the training, Advanced Nitrox/Deco Procedures/Normoxic Trimix. As others have pointed out, these are deco dives. As to why you might want to do all this, here is a good reason.

 

[scubadiver888]

One other note on cost to dive--l'll spend the money to go safe, or I'll skip the trip. The advice on gear is great so I don't waste any on gear I won't use. For example I'm thinking now of a steel 100 instead of the 120, so I can make a pair later since it looks like doubles are in my future. The point of the 120 was to cut down on tank changes between groups of students at the quarry. I'm also beginning to realize I'm going to need to go to a wing aren't I?

I assume your current BCD does not handle doubles. If you are going doubles then you'll need new buoyancy control. A backplate and wing would be the best choice.

Also, you probably need new regulators. Most cold water regs will work fine down to 100 feet. Some have trouble down around 130 if the water is near freezing. You get down to 160 and some regs are guaranteed to free flow.

Even if your regs are fine, diving doubles means another set of regs. Deco bottles mean another set of regs.

I looked into technical diving and it gets costly.

• multiple regulators
• not cheap regulators
• multiple cylinders
• O2 clean equipment (possibly)
• helium (not cheap and getting more expensive)
• BP/W

Add to that training and you can quickly get into $5000+. I've heard the gas for a typical dive can be $50 to $100 dollars. Quite different from a $7 air fill.