Performing technical dives on same boat with recreational divers

[Thalassamania]

... GOD?!?!?

It's an idiomatic expression, Jefferson and Madison did the same thing without being believers.

 

[Colliam7]

cape fear divers gave me the nogo on the trip. Apparently they aren't running at all. Aquatic safaris are booked for Sunday so I'm going to gamble on Monday to the city of Houston wreck...

For future reference, several of us have done this with AS at various times in the past. They are usually OK with it, if everyone agrees in advance to doing two dives on the same site, but will probably ask that you keep your bottom time to a value that requires a modest amount of deco at most. A total run time of an 60, even 75, minutes isn't bad, where you are geared up and ready to hit the water first, as soon as they are tied in and the boat is set up. A lot depends on the conditions at the site as well. So, 'if there was an emergency then we would have problems ' can refer not only to another diver having a problem on the first dive and needing to head back to Wilmington - while you still have a deco obligation - to the seas picking up during the first dive or the surface interval, to other boats tying in after divers are in the water for the first dive and the wreck getting crowded, to lousy visibility / current / whatever on the first dive, after which some of the others strat pushing for moving to another site - while you still have a deco obligation. That isn't necessarily a big problem, though, as they can send the mate down to let you know what's up, so you can perhaps start up sooner. IOW, it is not just an emergency, but a situation where all the other divers on the boat come up from the first dive and say, 'Let's go to another site for the second dive', after which they and the crew are then sitting there waiting for you, which does not make the captain, Paul in particular, very happy.

Haven't been out with the current incarnation of Cape Fear Divers, so I have no clue about them.

If the capt. is ok with you and the dive it has been my experiance that it is a widely accepted practice on the east coast on six pack boats. I do not think it would play as well on bigger boats.

Even on the bigger AS boat, it is doable, if site conditions are good for two dives, AND the other divers on the boat don't object to doing two dives on the same site. With AS, they are more likely to be flexible if they already know you. But, the majority (of paying customers) still rules, unless the captain vetos whatever they want, in which case the captain rules (as always).

 

[waterpirate]

How about you dump some air and add some he? That would make more sense and add more bottom time and even less deco with some clarity. 30/30 0r 30/20 is an amazing thing in 100fsw.
Eric

Seems to me that taking the time to dump some air out of your doubles and topping off with 02 to get a 36% (or even 32%) mix would make more sense. More bottom time with less deco obligation, and less risk to you should the boat have to leave early for an emergency.

 

[James R]

How about you dump some air and add some he? That would make more sense and add more bottom time and even less deco with some clarity. 30/30 0r 30/20 is an amazing thing in 100fsw.
Eric

He mentioned only ANDP. According to a 20 sec google search (which could certainly be wrong...I just don't feel like digging any further), the ANDP course doesn't train or certify divers for Trimix, thus my suggestion.

 

[waterpirate]

Different agency's and instructors introduce he at earlier moments than andp. A triox if you will. A 30/20 would be considered a triox and a recreational triox is available prior to andp with limited obligations. Not a snit, just an advocate for he sooner than later for clarity, bottom times are a side benifit, and with a rich deco mix a very doable option for tech lite in a rec setting.
Eric

 

[HowardE]

These kinds of dives happen almost every day on deep wrecks where recreational divers are allowed to do "double dips". I know several dive operations in Key Largo that do this on any one of the deep wrecks that are available to dive there, like the Spiegel Grove, the Bibb, or the Duane...

The problems pointed out are problems when ANY diver is in the water, and an emergency happens. Unless you are on a boat with a true emergency recall system, would an accident cause total recall of all divers in the water?

When ANY deco dives are being performed and IF there is an accident... you have the same problem (the people in the water whilst the accident victim may need to be rushed to shore). With or without recreational divers in the mix.

 

[CuNanoTube]

We had a solo tech diver on a boat with us doing wreck penetration. While down I noticed a yellow shape on the bottom. I investigated, noticed it was an oxygen stage and left it alone. One of the older divers in our group did the same (after I had left) and took it, thinking it had fallen of a boat. We saw him climbing the ladder with three tanks, realized what happened, and the stage was returned to the diver in time for deco. The guy told us he had enough back gas to deco, but was not happy about the incident.

My point: Discuss your plan if it is different from the rest. The older diver did not know what an oxygen stage was, and thought it was lost gear.

 

[Doppler]

He mentioned only ANDP. According to a 20 sec google search (which could certainly be wrong...I just don't feel like digging any further), the ANDP course doesn't train or certify divers for Trimix, thus my suggestion.

I teach advanced nitrox/deco procedures as a helitrox deco program... 20% helium in mix... Drops dad of the course max depth (45 m) to 30.



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[Spazzy]

Yeah I agree. Combining deco and nod-deco divers on the one boat is fine. The problem of what happens if an incident requires diver recall is the same for either scenario - you gotta wait until your divers have done their deco.

 

[Garth]

Yeah I agree. Combining deco and nod-deco divers on the one boat is fine. The problem of what happens if an incident requires diver recall is the same for either scenario - you gotta wait until your divers have done their deco.

I didn't get a chance to clarify this with the dive op before they canceled the dive but they made it sound like the deco would be cut short.