Vandenberg: depths and suitability of EAN32

[2airishuman]

I'm planning a dive on the ex-USS Vandenberg.

The charter operator who is taking me has suggested EAN30 rather than EAN32 noting that the deck is at 100 fsw and the MOD for EAN32 is 111 fsw. I have no intention of penetrating the wreck on these dives. Is the recommendation for EAN30 usual? Is it based on penetration dives, conservatism, or something else?

 

[doctormike]

Horizontal penetration wouldn't really impact on the gas choice. The wreck sits in 140 feet of water, so maybe they just suggest a slightly leaner mix so that you have more options below the deck (Rudder and propellers? Not sure).

I have dived it a number of times, on air, 30 and 32. Does the operator give you that choice, or is it just 30 or air?

If you are definitely not going below the deck, choosing a richer mix would give you longer NDLs, and there is a lot of relief, so plenty to see above 100 feet!

 

[dumpsterDiver]

So it is 140 ft max...I suspect he wants you on 30 so you can screw up and go to the bottom and not tox out. He would probably rather see you have a shorter dive than worry about some tourist "headin for the sand". That would be my guess, never dove there.

 

[kris@bulldogg.ca]

It seems as simple as a way to cover himself if something should happen, and probably a smarter idea anyhow.

Your planned depth limit on EAN 32 is 111 fsw, but the MOD is 132. If the bottom is 140 and something goes wrong he wants to control the risk. With EAN 30 your planned limit would be 121 but you MOD would be 143 fsw, which covers you to the bottom in a problem.

If you have not dove with them before, and it sounds like it is your first time diving that wreck so I would say that a slightly shorter NDL in this case would be worth it.

 

[longtimer]

If you drop your perdix, you will be at 140, hence EAN30. Not rocket science, just good sense. Why the pushback anyway?

 

[scubadada]

I did my only 3 dives on the Vandenberg in the summer of 2015. Huge ship, so much to see and do. My max/avg depths were 96/72, 102/73, and 121/68 feet. I only took a quick peek down a shaft midship on the 3rd dive or it would have had a similar max depth to the 1st two dives.

I just need to get back and look around some more

 

[doctormike]

If you drop your perdix, you will be at 140, hence EAN30. Not rocket science, just good sense. Why the pushback anyway?

Eh, I disagree. You should pick the optimal mix for the dive that you are going to do, to either maximize NDLs or to add safety. The Vandenberg is huge, with a lot of relief and most of the interesting stuff above 100 feet. If you are doing this dive as a nitrox certified diver, you should be situationally aware enough to be able to avoid falling off the deck into the sand.

To say that you need to always dive a mix lean enough for the hard bottom is an argument against any sort of wall diving.

 

[stuartv]

I'm planning a dive on the ex-USS Vandenberg.

The charter operator who is taking me has suggested EAN30 rather than EAN32 noting that the deck is at 100 fsw and the MOD for EAN32 is 111 fsw. I have no intention of penetrating the wreck on these dives. Is the recommendation for EAN30 usual? Is it based on penetration dives, conservatism, or something else?

Is it because they have EAN30 banked and they have to blend to get 32? The shops I've dived with in NC all bank 30%.

If one is banked and the other is not, I'd take whatever is banked.

2% doesn't make THAT much difference on NDLs that I would fret over it at all.

 

[Diving Dubai]

2% doesn't make THAT much difference on NDLs that I would fret over it at all.

You beat me to it. I ran it through the planner for my computer with At 33m the time difference for NDL was about 2 minutes. Meh!

 

[doctormike]

Is it because they have EAN30 banked and they have to blend to get 32? The shops I've dived with in NC all bank 30%.

If one is banked and the other is not, I'd take whatever is banked.

2% doesn't make THAT much difference on NDLs that I would fret over it at all.

Yup, if they only have banked 30, then dive that.