Farnsworth Banks accident last weekend?

[diverrex]

I'd like to think that if I ever took my last gasp of air and was having trouble getting to the surface I'd have the presence of mind to drop weights. But I think I'll continue to not come close to that possibility by watching my air.

I am not sure how you start a descent at let's say even 120 FSW with 1200 psi and go OOA. Unless you did a lot of horizontal swimming trying to find the anchor line. I'm assuming if they are doing Farnsworth they at least have a 100 cu ft tank but that may be a bad assumption. Does anyone know the tank size?

If the diver had an AI computer it would be real interesting to see the data.

If a diver makes it to 15 FSW and doesn't have any air in the tank I find it a little hard to understand how they don't make it to the surface without some kind of medical issue occurring or by being overweighted. But I suppose severe panic could cause all kinds of issues.

 

[uwxplorer]

I was not saying that the rule of third is taught to recreational divers (it might, I am not sure; however, it is to SDI solo divers though, and they are moreover supposed to carry an extra 1/3 of bailout). I am simply suggesting that it is a good idea, which I have validated ad absurdum each time I turned a dive later than this and things turned iffier than expected (but I had bailout and never had to use it). It is an excellent idea in a deep dive.

Thanks to Randar for clarifying some of the circumstances.
There is no reason to point fingers at the buddy. Clearly, they did not anticipate the outcome of the events and hindsight is 20/20.

Separating in blue water is not fundamentally a good idea, but maybe the boat was adamant that they should come back up the anchor line and he was hoping to get a bearing on it for them to "officially" come up the anchor line? I have heard that in briefings several times on trip to the place and elsewhere, and obviously what that means is not that you cannot pop up in the middle of nowhere, but that is not what you want to do if you can at all avoid it. Boats probably should say (and they do) that if you can't, just surface calmly after your safety stop, signal to the boat and swim back at the surface. There is no real advantage of not doing so in a no boat traffic zone with no kelp forest to waddle through. The idea to take a bearing would have made perfect sense in those other two circumstances, provided the next factor would not have been at play:

Maintaining a constant level at 15-20 ft, alone in blue water (with no reference: the top of Farnsworth is at ~60 ft if I recall correctly) and without the help of an SMB is not easy feat without practice. I am not even sure that it is easier with a buddy (especially if your buddy is a yoyo master). Maybe the diver was trying to NOT pop-up at the surface and yoyo-ing in the water while trying to look at his buddy or finding a reference on the bottom? Again, this is not a trivial situation to handle at the end of a dive and the associated stress.

Not dropping weight is certainly a major and final factor, but that "decision" is apparently difficult to make when you are fighting with an array of issues projecting you far away from your comfort zone and without the benefit of rehearsals. This is hopefully the lesson that will save the life of one of us in a totally different series of unexpected events.

 

[Power Scuba]

I have yet to see a diver start ascending at 1000 psi which is what the rule of thirds would indicate.

Actually, I know many divers who practice this behavior... and some have never heard of the tech "rule of thirds". Some open water courses (as well as Advanced courses) teach that it is mandatory to be at the bottom of your up line with at least 1000 psi (or more) in your tank.

Bill

 

[Chuck Tribolet]

I have yet to see a diver start ascending at 1000 psi which is what the rule of thirds would indicate.

I do, except on some shallow (50'ish) sites. If there's a current running, I'll start up at 1200 PSI. This is on a 3500PSI HP 100.

On our favorite site, on Nitrox, it works out to a good balance between Nitrogen loading and gas supply. My computer usually
goes into the yellow as I'm swimming over to the anchor line.

Chuck

 

[drbill]

One beautiful thing about diving Catalina is that the steep offshore slopes allow me to begin my ascent from depth early (sometimes with 2,000 psi or more left) and enjoy a leisurely uphill ride stopping with plenty to film along the way. I am not a big fan of square profiles.

 

[Fin Finder]

I have dived Farnsworth Banks several times, and have experienced a variety of underwater conditions there. It is truly a beautiful and unique location, but one thing I always keep in mind is navigation on this site can be very tricky. I have found that keeping track of compass bearings and distance traveled are critical to avoid an air depleting search for the up-line at the end of a dive.
My impression of Fransworth Banks is of a series of steep pinnacles connected by narrow saddles that form a kind of winding underwater ridge line, which does not reach the surface at any point, and is surrounded by deep water. This is probably an oversimplification, and no doubt other readers of this board can provide more detailed descriptions. What makes this site tricky, in my opinion, is without good navigation, including an accurate heading back to the up-line, it’s all too easy to go in the wrong direction when returning. I know this, because even with 1000+ Cali dives, I’ve done it; fortunately without coming to too much grief, although not without expending a large portion of my air reserve to find the up-line.
One might ask why it’s so critical to return to the up-line at Farnworth Banks. Why not just make a free ascent when the air supply gets low? The reason a diver may push into his air reserve to find the up-line lays in the location of Farnworth Banks. This site is isolated, far from land, with nothing but the vast Pacific to westward, and accessible only by boat. It is occasionally subject to strong currents, and exposed to wind and surface chop. The prospect of surfacing away from the anchored boat in the current, and being subject to drifting away in open water until the boat can recover it’s other divers and unhook, is a rather frightening prospect. So, extending one’s bottom time to find the lost up-line may not be the prudent thing to do, but it’s understandable.
Most of the local dive boats visit Farnsworth Banks several times a year. It’s a very popular spot. The boats and dive shops I am familiar with require at least an AOW cert for this dive. Unlike other dive regions, most local boats do not provide cylinders. I’ve seen divers board with anything from ST72s and AL80s, all the way to ST120s. I’ve never seen a diver advised not to dive because of tank selection.

 

[Hatul]

I was on the boat (Vision) and in the water. There was a fatality. Here are the basic details:

Diver (Fatality) had over 100 logged dives

The bank (Farnsworth) was about as pristine as I have ever seen it. No current. Hardly any surge and about 50-100+ feet of vis. Made a dive to 130 +/- and then back to the boat. Accident happened after I got back.

Both Diver and his buddy made it to safety stop, but did not come up the anchor line. Buddy had an OOA situation and came to the surface. Said other diver was "Venting" his BC and descending. The crew of the Vision reacted in a trained and expeditious manner, but were unable to locate the second diver. He was later found OOA and at the bottom.

Was a sad incident all around, but I cannot find any fault in the reactions/actions of the crew or the dive buddy. They did what they could.

I don't want to sound too critical after a fatal accident, but it's obvious there were at least two serious errors here. Not only are you not supposed to run OOA but you need enough for your buddy in case. If you don't have an AI computer a useful rule of thumb is to have PSI>= (depth in feet)*10 + 500. So at 100 feet have at least 1500 psi to allow yourself enough for ascent and to share if needed. If you have an AI computer, Oceanic, UWatec or Cobalt, if you ascend before your RBT>0 you're unlikely to run out of gas. An if (RBT in mins)> (depth in feet)/30 +1 and have a reserve set to >550 psi, you'll have enough to share with your buddy as well.

The most likely reason the diver panicked and emptied his BC with an OOA buddy is that he was OOA as well. Using an AI dive computer would likely have prevented this death. IMO.

Just to add: there is a good article on AI in the latest issue of Undercurrent.

 

[MXGratefulDiver]

I have yet to see a diver start ascending at 1000 psi which is what the rule of thirds would indicate.

I'm not sure where that rule came from, but it is not the rule of thirds ... nor does it in any way indicate whether or not 1000 psi is enough gas to surface safely in the event of an emergency.

The rule of thirds was created as a tool for diving in overheads ... and even then it's more a rule of thumb, since in many circumstances it wouldn't give you adequate safety margins. The rule stipulates that you use one third of your gas for going in, one third for coming back, and one third in reserve in case of emergency. In other words, if applied properly you should be back on the surface with one-third of your available gas remaining in your cylinder. It's a very conservative way to do recreational diving, since the ultimate bailout in recreational diving is a controlled ascent directly to the surface.

The concept of beginning your ascent with 1000 psi in your cylinder is better than not having a plan at all ... but it's really a WAG when it comes to answering the question "If my buddy gave me an OOA signal right now, would I have enough gas in my tank to get us both to the surface safely?" ... and this is always the ultimate gas planning question to be answered, since it addresses the worst-case thing that can go wrong from a gas management standpoint. You cannot meaningfully answer that question without considering (a) how much gas you and your buddy use, on average (i.e. your gas consumption rate), and (b) how long will it take us to ascend to the surface. Naturally, the deeper you are, the faster you'll consume the gas in your cylinder, and the longer it will take you to make a controlled ascent. So saying "begin your ascent with 1000 psi in your tank" won't help you determine the answer to the question without knowing your depth and consumption rate at the point you begin your ascent.

Now consider some other factors ...

- if one of you is OOA and you're sharing air on the ascent, you're probably going to be working harder and breathing harder than normal
- when was the last time you actually practiced a shared-air ascent? They're not as easy in real life as they were when you did simulations in OW class ... and if you haven't practiced since OW class, you're probably not even as good at it today as you were back then.
- what are the conditions like? Cold water, dim light, current, kelp, and a host of other things can impact both your ascent time and how hard you have to work to make it to the surface. These will, in turn, cause you to use more air.
- how big is your tank? If you're using one of those oversized beer cans that a lot of recreational divers like to use, then you don't really have a lot of gas to play with ... about 26 cubic feet at 1000 psi. You'd be amazed how fast two stressed out divers can go through that ... especially new divers, who tend to burn through their air faster than they will once they've got some experience under their weightbelt.

Bottom line ... following something like a "rule of thirds" is better than not having a gas plan, but it doesn't really tell you whether or not you have adequate gas for dealing with the unanticipated worst-case of an OOA emergency. Blindly following any rule without understanding how it works, or whether or not it will provide you with enough gas to make it to the surface, can result in an OOA emergency.

... Bob (Grateful Diver)

 

[Chuck Tribolet]

Using an AI dive computer would likely have prevented this death. IMO.

IF the diver looked at their computer, and knew enough about it to know what it was telling him.
A depth gauge and SPG would have done the same thing.

The only dive computer that counts is the one that sits a couple of inches behind the mask.

Chuck

 

[drbill]

I want to clarify that Farnsworth Bank is not a "typical" Catalina dive site since the peak is well below the surface (at about 60 fsw for the site we dive), so there is no option for a gradual swim upslope here. I have dived it several times, generally with a 120 and a 19 pony. One time I did incur a significant deco obligation and ran low on air. Other times I have been in poor conditions where I could not find the anchor line and have had to do blue water deco stops. It is considered an advanced dive and all boats I know of that go there require at least AOW certification. Again, my condolences to the family and friends of the deceased.