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Blue Hole Arch of Dahab Egypt

Discussion in 'Tech Trip Reports' started by divezonescuba, Jul 16, 2019.

  1. divezonescuba

    divezonescuba ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Houston, Texas
    1,320
    375
    83
    We spent 9-15 June 2019 in Dahab, Egypt. We stayed at the Red Sea Relax resort in the center of the Lighthouse area in Dahab. Our technical diving was supported by Team Blue Immersion which is associated with Dahab Divers.

    One of the owners Andy was our primary point of contact. Khaled was our shore supervisor. Saleh was the gas blender, and the drivers / shore assistants were Akmed (Tarek Omar’s driver / shore support) and Mansour.

    Team Blue Immersions location is not obvious. You must travel thru the Dahab Divers courtyard and then up a short driveway. Despite the fact that they are located in the same building and on the floor above Dahab Divers, no one at Dahab Divers would acknowledge who or where Team Blue Immersion was.

    There is a classroom inside. There are lockers on the patio with small crates. Wetsuits and divegear bags are stored in a locked room below the patio. We used the same backgas and deco tanks each day.

    Our first day of diving was designed as a debugging dive day at Lighthouse. It took a few hours to get set up including adjusting the stud lengths to get the twinsets to fit our plates. You walk down the driveway and thru the courtyard to access the water. You enter the water thru one of the many waterside restaurants.

    The shore support person generally handles your deco tanks from the time you leave the shop to when you don them in the water. They then monitor you while you are in the water and assist you exiting and returning to the shop.

    The next four days were spent at the legendary Blue Hole. We met at the shop each morning at 8 and analyzed and marked our tanks. The driver / shore support person loads the gear in the truck and you are off by 0830. The ride to the blue hole is approximately 20 minutes. You go past the Canyon area on the way to the Blue Hole.

    The Blue Hole is ringed by open air restaurants. Our truck pulled up right next to the entrance point. Typically, we would stake out an area at the Aqua Marina restaurant, drink a water, and preorder our lunch. After that we did the equipment setup.

    It is a little bit difficult getting in the water due to the small rocks on the path and underwater. A bigger problem is the numerous snorkelers and waders who sometimes block the narrow path to the deeper water for no apparent reason. Frequently, they leave their flip flops on the path to the water while they are in the water. It is also sometimes difficult getting out of the water due to the same traffic. Tripping on a flip flop and falling down or falling on top of one of the snorkelers was certainly the greatest danger that I encountered diving the blue hole arch. Fortunately, we frequently beat the snorkels to the Blue Hole in the mornings.

    Since two of the divers were taking the remainder of a PADI trimix course, our dives were planned around the skill and depth requirements of each dive. Typically, we would enter the Blue Hole and descend on either the inside or outside depending on what we were doing that day.

    Day one, two dives, primarily skill dives and recon of the arch, deco on the outside of the hole
    Day two, pass thru the top of the arch and deco on the outside of the hole
    Day three, pass thru the middle of the arch, pass thru back to the inside, deco on the inside of the hole
    Day four, pass thru the near the bottom, pass back thru to the inside, deco on the inside.

    We used, tmx 21/20, tmx 18/30, tmx 16/40, and tmx 14/50 as our bottom gasses. X32 and x100 as our deco gasses, and tmx 21/20 as a travel gas on the deeper dives.

    After we put away our equipment we would go back to the restaurant for lunch. I had the chicken kebab every day which was so good, I would eat it every day if I could.

    We would then return to the shop where Team Blue Immersion would rinse off our tanks and put in the next days fills.

    All of the dives were fantastic. The support provided by Andy, Khaled, Saleh, Akmed, and Mansour was more than you could ask for.

    We did make one serious mistake one day. One of the divers only had a yellow dsmb. There a yellow dsmb means emergency. Andy swam out to see what the problem was. Apparently is is especially serious if you launch one after an Orange dsmb, like we did, during the course skill.

    We had such a good time on this trip that our once in a lifetime trip has now become an annual event. Dahab’s recognition as a prime technical diving site is well deserved. It is very easy to obtain the depths needed for full hypoxic trimix courses. Unfortunately, we did not have a chance to technical dive at other sites such as the Canyon area.
     
    decompression likes this.
  2. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    9,315
    3,289
    113
    what depths are you using these gasses for?

    They are all new to me but 21/20 is especially odd when you had EAN32 along anyway.
     
  3. Khrissi

    Khrissi Nassau Grouper

    # of Dives: 0 - 24
    Location: London
    149
    87
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    Looks fascinating dive but not for me..... Yet. K
     
  4. divezonescuba

    divezonescuba ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Houston, Texas
    1,320
    375
    83
    The depths were limited to 1.4 pp o2, an END of 130, and the PADI dive depth limits for each dive. We used 30/70. We used AL80s for the backgas and AL40s for the deco and travel gasses. The dives were planned with the one third reserve.

    The tmx 21/20 was used as a travel gas on the descent to conserve the x32 deco gas and on the ascent to prevent IBCD.

    We switched from travel gas to bottom gas on the descent at 150 feet and from bottom gas to travel gas on the ascent at 150. We switched to the x32 on the ascent at 110 feet.

    The submission of dive plans are required before each technical dive. I do not think that Andy would have approved us to do the deeper dives without a trimix based travel gas, particularly since we were using x32 rather than x50 as our first deco gas.

    Also, we were initially somewhat concerned about the whole terrorism thing since Egypt particularly Sharm and Dahab have had issues in the past. Security was heavy everywhere. When we arrived in Sharm, we did have to wait to go to Dahab until a sufficient number of vehicles had assembled to form a convoy with a police escort. There was one checkpoint between Dahab and the Blue Hole and another at the Blue Hole.

    Our total group size was 13. We initially though about safety in numbers. We may have not made the trip if it had just been the two of us. However, we felt safe in Dahab and were quite surprised when another American told us that we were the first Americans that she had met in Dahab in 10 months.
     
  5. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    9,315
    3,289
    113
    I'd encourage you to have a peek at this thread and back off the gas densities.
    Gas density guidelines

    'Cause science
     
    blake7 and RyanT like this.
  6. divezonescuba

    divezonescuba ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Houston, Texas
    1,320
    375
    83
    Funny that you mentioned that. We we a bit over 6.0. An Instructor Trainer told me not too long ago that he regularly did air at 200 feet which i believe is over 8.0.
     
  7. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    9,315
    3,289
    113
    Anecdotes about what someone else got away with are probably not the best way to progress as a technical diver.

    There's a wealth of scientific evidence and rationale upon which to make some educated choices about things like density, END, IBCD, EAN32 as a deco gas, 2x al40s for deco from a 60+m dive, and bringing a 4th gas as a travel gas.
     
  8. divezonescuba

    divezonescuba ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Houston, Texas
    1,320
    375
    83
    I would be interest in any references / discussions on the use of a travel gas as the 4th gas.
     
  9. beester

    beester DIR Practitioner

    # of Dives: 1,000 - 2,499
    Location: Belgium / Italy
    695
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    Heya divezonescuba....

    Really enjoyed your report. Great that you had a lot of fun. Been a lot to the red sea (one of my favorite tropical diving spots) but unfortunately never been to dahab, so always curious reading up on someones experiences there.

    Regarding gas choices and deco strategy... I have to follow rjack. I don't like nitpicking at others diveplans or decostrategies... because it's not black/white, and people rightfully get defensive about their plan. But since you are a full trimix instructor I think I can comment (taking into consideration that I have no idea on what your actual bottom times were or your ascend strategy):wink:

    - 32% as deco gas: I don't understand the rational for this deco gas. There is just to big a gap between your 100% and 32%. You are doing a big part of your deco in the 70-30ft (21-9m) range diving a less optimal deco gas that is really not creating enough gradient to efficiently off gas he and N² in the part of the ascend where you are spending the majority of the time. Was there any gas logistics behind this for not using for example a 50%?

    - Travel gas vs your hypoxic gasses: In my practical experience a 14/xx tx is indeed hypoxic. But at 10ft (3m) depth it's already perfectly breathable. So as long as you have the discipline not to breath it at the surface you are ok, eliminating an additional tank and reducing equipment stress.

    - 4th (travel/deco) tank: Having said that... I can understand the 4th tank as a way to increase bottom time. Or as a bottom stage or as a deep deco gas (which allows you to decrease the ascend to first deco gas switch and like this increases your useable gas on the bottom).

    Anyway like I said... no critique... just comments on how I would do it :wink:
     
    rjack321 likes this.
  10. divezonescuba

    divezonescuba ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Houston, Texas
    1,320
    375
    83
    Since some of you seem interested in the choice of the x32 as the first deco gas, it does indeed originate due to logistical issues. We could have used a standard gas, x50, but chose not to. I would get into that, but I am sure that would set off an entirely new discussion. I myself was trained under heavy GUE influence and if you didn’t use x50 and x100, you were wrong. We went straight from tmx 14/50 to x50. Not saying that is right or wrong, it was just what happened during the course.

    On the subject of the travel gas, this was primarily a sequence of training dives. From my perspective, it is desireable to introduce students to as many useful skills as practical. This includes the use of travel gasses whether or not the are absolutely necessary, getting used to more than two deco / stage / travel cylinders, and bottle rotations in a trimix course. Training time is valuable and the most should be made of it. Again, from a training perspective, the use of a hypoxic gas to descend from the surface would probably be a training standards violation, even if it was no longer hypoxic shortly after descending and had little practical effect.

    While I was taking the trimix instructor course, I was taken back a bit when one of the candidates disclosed that he had never done a bottle rotation before. I also received the impression that he had not dove with more than two deco / stage / travel gas tanks as well. Whether or not he had ever used a separate travel gas bottle was another question.

    Doing something like using a travel gas, using more than 2 deco / stage / travel gas cylinders, or having to do a bottle rotation for the first time on a non-training deep technical dive is not the best idea in my opinion.

    I am thankful that my original trimix instructor had me do all those things during my course.
     

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