3 Missing in deep dive incident - Mexico

[BladesRobinson]

I dont understand how there could be a current strong enough to suck people underwater - given the fact that we should be able to get 10+ lbs of bouyancy right away with our BCs. Would take a hell of a current to do that, and downward currents seldom just appear and hit that rate. Ive never heard of it, or a mechanism able to create it.

I pass along an earlier quote from a newspaper article and also mention that reports from a dive computer worn by the sole survivor indicated (if my memory serves me correctly) a descent rate of nine feet per second. Readers can draw their own conclusions and the real fact is, no one really knows exactly what happened other than the end result, three divers disappeared in the same instant and one diver was nearly pulled to his death.

Earthquake. In addition, it is possible to emphasize that two days before (at 20:26 hours) an earthquake of 3.8 on the Richter scale was registered, with epicenter to 109 kilometers from Vallarta Port, at a depth of 13 kilometers. Specialists have indicated very insistently that the Bay of Banderas is in a zone of high seismic activity, and indeed the canyon in reference has been related to the faults that exist in the region.

Landslide? It was then that the movement may have exacerbated the conditions that led to a collapse in the day on November 30 and dragged the material to 300 or 400 feet deep has been estimated that point. Here it should be noted that the bathymetry done so far is insufficient to provide accurate data on the matter. Had it happened earlier, the divers could have been taken away by the tide and even if the material covered by the collapse. All this could only be corroborated with the sophisticated equipment expected by UEPCJ to search for the divers. A remote operated vehicle (ROV) would be appropriate in such cases, according to specialists.

 

[z3r0c00l]

I know what they say, but to get water to do that is very difficult and uncommon. Sometimes people just forget to use the BC and sink like a stone, without any currents. Add currents to the equation, and the fear factor probably only increases.

 

[BladesRobinson]

I know what they say, but to get water to do that is very difficult and uncommon. Sometimes people just forget to use the BC and sink like a stone, without any currents. Add currents to the equation, and the fear factor probably only increases.

One could possibly question the account of a single diver who might lack control of his buoyancy but I don't buy into the idea that four divers at the same instant couldn't control their buoyancy. Combined with witness statements (from the boat crew) that the surface float was also pulled underwater at the same moment supports the theory reported in the newspaper article previously quoted.

Unless a forum reader can state they have some experience diving in proximity to underwater geological shifts, or have first hand knowledge that the water currents are mild or don't follow the direction of the slide, then I will place some belief in the theory reported by authorities and quoted by the newspaper.

If someone can come up with a better theory that is more plausible, then let's hear it!

Granted, having divers in the water at the same moment the bottom shifts is unlikely, so is loosing three divers in the same moment, almost loosing a fourth, and having a surface buoy pulled underwater. Seizmic activity that was recorded by multiple sources and witness accounts from the boat crew, the survivor and at least one experienced SCUBA instructor support the conclusion reported previously.

 

[Mike]

This absolutely scares the crap out of me. We just returned from Puerto Vallarta, we dove with Chico's and did the Marietas and were trying to get a dive at Chimos with Boca Divers, but didn't end up happening because the other divers needed to make the minimum for the dive shop backed out.

We passed Los Archos on the coastal road 3 different times going to Boca de Tomaltan just south of PV and I saw the Policia white suburban parked backwards nose out to the road each time and saw an officer always standing there leaning on the truck. Very strange to us since you have to search far and wide to spot the police anywhere in PV and we kept seeing this unit there.

During our dive to the Marietas our dive master told us about the los archos incident that happened the week before we arrived. Chimo is an advanced dive due to currents and is considered much more difficult/dangerous then Los Archos, and now I kind of feel like someone who missed their air plane flight and is upset, and then learns hours later that the plane crashed.

I have never been aware that currents could kill you. The worst case I thought was they might drive you away from the dive boat and carrying signalling devices would be a way to be prepared for this. But currents that would drag you down so fast to kill you just gives me shivers. If dropping your weight belt and fully inflating your BC aren't going to save you, this gives me pause to ever dive anywhere without a bottom under me.

 

[z3r0c00l]

I dont even understand where the water would go. How can surface water be pulled down at a rate of 4+ kts (I would expect it would take 10+ kts to pull a diver down with weights dropped and BC inflated fully)? Where does it go? I ask as an oceanographer - not just a layperson. I visited the worlds largest whirlpool, where billions of tons of water are moved each day. Sometimes the visible funnel is large enough to hold a car. But even then, things dont get sucked down. Most of the motion is laminar. This is a pretty scary, and confusing report.

 

[Ayisha]

...weights dropped and BC inflated fully...

I don't think you'd want to drop your weights at depth in a down-current. What would happen if you are able to kick your way across and out of the current? Or apparently the downcurrent usually lets up within 30 - 50 feet or so. Then what? A polaris to the surface - not good.

I can't believe how surprised you appear, considering you are apparently an oceanographer. This isn't the first time down-currents are being publicized. Usually they let up quickly, however, and the people live to tell about it. Two friends of mine were caught in a downcurrent in Cozumel 4 years ago, dragging them both from 80 - 130 feet quickly. The instructor/leader was on the edge of it and kicked his way out, and most of the group saw the two divers fall quickly by the wall.

I got caught in a downcurrent innertubing through 7 miles of caves in Belize 2 years ago. We were the first group allowed to go through in a week due to flooding and very high and fast moving water. Some caves were impassable due to no breathing space. We were going through a cave that was particularly challenging and several people opted out and crossed by land outside the cave system. We were daisy chained together linking arms and legs and a trainee at the front was leading us through getting closer to the wall. The leader in the back yelled "Kick away from the wall! Get away!!". We all separated and tried, to no avail. Before I could kick away from the wall, my tube flipped, and I plunged 15 - 20 feet underwater, WITH a lifejacket on. I held my breath and kept kicking up, but I wasn't going anywhere. I saw the current and silt going down the wall. I thought I was going to die. I remembered what he said, and kicked as hard as I could off the wall and kept kicking. All of a sudden I flew up and I was on the surface, gasping for air, flying with the current toward the exit, my headlamp lost. The leader was standing in shallow water holding my empty inner tube, panic stricken. They were so scared that I was in shock, but I was fine.

Yes, down currents do exist, particularly near walls.

 

[BladesRobinson]

I just spoke to the last ROV pilot to return from the scene and his information is unbelievable. By that, I mean hard to believe and if the information was reported by anyone else, I would say it wasn't accurate.

A representative from VideoRay went to an area where an earlier ROV pilot reported strong currents in a hole (cave like siphon) with a depth greater than 300 feet. Within 14 days, the VideoRay pilot reports no current and a sandy bottom at 200' at the SAME location. The VideoRay pilot returns to the same spot several days later and again finds no current and the bottom now at 100 feet. The oval shaped opening was approximately 6m x 13m and is apparently filling in.

For the oceanographer (z3r0c00l) I would ask… What do you think?

I would hate to own oceanfront property in the area and I suspect some sound research is needed in the region. My opinion.

The underwater search has been terminated.

 

[peterbj7]

I haven't read this whole thread, but I can confirm that major down currents can occur. An example is at Ras Mohammed, at the southern tip of the Sinai peninsular in Egypt. Starting at around 20m there is a down current that it is difficult to make any headway against, even with a full BC and finning strongly upwards. The solution in that case (other than listening to your dive briefing and not getting into it in the first place) is to swim strongly away from the wall. Suddenly you're out of the current.

 

[jerrycsr]

So if you are wall diving and get caught in a strong down-current, do you generally swim away from the wall?

 

[saipandiver]

Just as a reference, what is the current speed at Peleliu Express when it is really ripping, yet still diveable? Or what about the strongest currents at Blue Corner (again, when possible to dive?) How do these current speeds compare to the downcurrent discussed in this thread? Thanks.