MOD Stickers

[stuartv]

increased risk of a seizure if you are working hard due to current as well as a bunch of other physiological stuff that is less than ideal for extended exposures. Limited ability to do repetitive dives due to otus, etc.

Yes. I'm aware of those risks. If I was planning a dive where I was concerned about stiff currents, I would be more conservative in a number of ways, not just O2 exposure. If I were planning the first of a series of dives, ditto.

Fortunately, because I'm not compelled by my training to choose from a limited menu of gases, I can plan more conservatively very easily without being forced into big compromises.

 

[RyanT]

In talking with people who've actually been in that situation, apparently, yes, the CG will request this.

 

[tomfcrist]

Stuart, what he is saying is that the SAR helo isn’t always available...sometimes a fast boat is the response. Either way the answer to his question is this: Captain tells USCG that there are divers in deco under the boat. The USCG isn’t going to tell the boat to leave them in the water and split, nor drag them to the surface and bend them.

In the scenario Ryan brings up, the cardiac guy better hope the helo is available, because he’s probably gonna die without it...regardless of the ability for the boat to pull anchor and run to shore...40 miles? That’s a 2.5hr run for the majority of commercial dive boats.

I don’t know how much further off topic this is going to be allowed to travel....the mods must be entertained.

 

[tomfcrist]

In talking with people who've actually been in that situation, apparently, yes, the CG will request this.

They will request it...but not with divers in deco.

 

[RyanT]

The CG's view is to get the person in distress to shore, as quickly as possible, where they can receive the best possible medical care. Keep in mind that the divers are only one part of the CG's pervue. They often deal with fisherman (commercial or recreational), sailors, the crew of commercial freighters, etc. With that mindset, getting someone to shore as quickly as possible is the most prudent decision. Divers present a different problem when the boat cannot simply pull anchor.

 

[tomfcrist]

Totally get that Ryan, but they are very familiar with the challenges of rendering assistance to dive operations.

 

[RyanT]

I don’t know how much further off topic this is going to be allowed to travel....the mods must be entertained.

No, no, this has everything to do with standardizing MOD stickers on your deco tanks!

 

[Michael Guerrero]

I couldn't read 12 pages about MOD stickers.

I have permanent stickers on deco bottles and duct tape and marker on stage bottles. Deco bottle MODs are 1.6ppO2, stages are 1.4ppO2. Result is the same in that I obey the MOD.

Based on where I live, and how few tech divers are around, extra bottles cost me usually near full price.

 

[kensuf]

I'll play.

75 minutes at 130' at 1.4PO2 with some helium (28/20). Deco on 50% and 100%. GF 40/75. Total r/t 132 minutes.

75 minutes at 130' at 1.2PO2 (25/20). Deco on 50% and 100%. GF 40/75. Total r/t 137 minutes.

5 minutes additional deco is negligible, but the lower working PO2 on the bottom has several benefits, including overcoming sensor inaccuracy (+/- 1%) and gives you a margin if you need to adjust and go a bit deeper than the planned max depth.

Having said that, I tend to agree with those that say running a 2+ hour schedule in the open ocean is kind of risky behavior. There are places I wouldn't hesitate to do this (some place with a secluded wall / cove that the final 20' of deco can be well protected), but there are other locations where the risk/reward can be too great (I know, if I was in Bikini I may feel differently, but I could do multiple shorter dives and manage the weather variables easier).

 

[KevinNM]

Why 1.4? Because it gives me a longer bottom time and less deco than 1.2.

I’m told the reason GUE uses 1.2 is because people have drowned from CNS oxygen toxicity at 1.3 and above.