136ft in no time

[diver_doug]

I don't know that this qualifies as a near miss exactly, but it was definitely an eye-opening experience and a lesson learned. I solo dive often (I don't have a ton of dives under my belt, but about 60 of them are solo. All of my diving has been shore-diving and, given that I live in SoCal, depths typically range from about 20-50ft (my only deep dive was for AOW, but that was only down to 85ft). A couple of weeks ago I decided to check out La Jolla Canyon (a series of walls decending down to over 500 ft). I did a fairly long surface swim and decended down to about 35ft and then started heading out towards the first wall. I had checked out a map of the site online, it showed there was a wall at about 65ft, and then a second at 143ft (I was only planning to go the 65ft wall). So anyway I'm swimming along, I check my depth and I'm at 55ft so I figure I should be getting close. I continue swimming along thinking that I should have arrived at the 65ft deep wall by now, I look at my depth gauge and I'm at 136ft! I would say the transition from 35ft to 136ft took all of about a minute. I knew I was only 6ft beyond rec limits, so I figured since I was already there I may as well hang out for a couple of minutes (in hindsight this seemed like a totally stupid idea). I did just that, and then realized after about only 5 minutes total in the water that I was already down to 1700psi (alum80, plus 19cf pony). Although I wasn't exactly dangerously low on air I was amazed how quickly air depletes at depth (intellectually, I already knew this, but it was different to actually experience it since I was so accustomed to 45-60 minute dives). I was able to ascend with no issues, do a safety stop, and surface with about 700psi. So I guess my point here is to warn new divers, or divers accustomed to shallow dives that: if you are in an environment where you are able to go deep, BE CAREFUL! It was nothing to go down to 136ft, and I feel it would have been easy to go down to 200ft...and it would have been easy to hang out there for a few minutes only to find myself at 200ft with with no air (except for the 19cf in my pony). The depth and air depletion sneaks up quick and one needs to keep a constant watch on depth and PSI to avoid disaster.

 

[Jax]

Do you think you might have been in a down-welling? Could a current have pushed you down without your noticing? Thank God you caught it!

 

[Bubbletrubble]

@diver_doug: Thanks for the warning. Glad you are OK.

How familiar are you with the area?
Were you diving Scripps Canyon (not accessible at all)...or was it really La Jolla Shores (much more accessible to shore diving)?
Where did you enter and exit?

The reason I'm asking all of these questions is that it's quite a long swim to reach 136 fsw if you kick out directly west away from Vallecitos St. It would take someone who is not familiar at all with the site to go that far out. It's a long, looooooong kick out.

I'm very familiar with this site. It's used quite frequently by OW classes for certification dives. It would be highly unlikely that a down-welling contributed to the OP unintentionally descending to 136 fsw.

Solo diver...less than 100 lifetime dives...diving an unfamiliar site...not watching his depth gauge (surprised to find himself at 136 fsw)...doing a deep dive with an AL80.
Kids, don't try this at home!

For future trips to the La Jolla/San Diego area, I recommend that the OP join the Divebums.com email list and solicit local dive buddies.

 

[redacted]

Where do you wear your computer/depth gauge? What were you looking at as you moved along for that minute?

 

[NC Wreck Diver]

I love to solo dive, and I have some good experience under my belt. IMHO, you may want to rethink solo a little more with your skill level. If you feel cool, then ignore what I have said. Tell me, what about the pressure in your ears? Sounds to me that you would need to equalize many times to get to 136 feet. It's a good indicator of your actual depth, even is you weren't monitoring your depth guage (which of course you should have been). Yes, you will burn your back gas fast at that depth, and a 19 pony will give you just a small margin at best. I sling a 30, and that seems small when you are approaching 140. Just some food for thought. Take it or leave it. Bottom line, I'm glad you handled it all well and you are OK.

 

[scubafanatic]

Also, many dive computers can be programmed to warn you (beep) if you surpass/break certain limits (depth, air-dive time remaining) so especially for a newbie-ish diver having a computer warning you would be a backup way to be reminded you are exceeding certain paramaters.

 

[TSandM]

One of the insidious things about diving is that it feels pretty much the same at any depth. But I usually notice the decrease in light as I get around the 100 foot range -- but not if there is a really dense surface layer of crud.

One of the things to be aware of from this story is that your decision to "hang out" there for a while was probably influenced by some narcosis. You don't have to feel drunk or fuzzy to be narced; making poor decisions or being less than vigilant is a symptom, too.

 

[diver_doug]

I'll try to address all of the comments:

I entered at La Jolla shores but I believe I entered too far North. I decended around the yellow buoy (entered near the life-guard tower).

The whole time I was descending there was seafloor below me. I realize not keeping my eye on the depth guage was stupid (normally I'm very good about this) but based on descriptions I have read about the canyon, it sounded to me as though I should come to an obvious "underwater cliff" at about 65 ft so. I was looking for the cliff and I didn't realize how steep the floor was. I guess I had cliff "landmark" in mind and wasn't as thorough with checking my depth as I ought to have been.

My computer does have a depth alarm, but it's not very loud and with a hood on I almost never hear it (it's sherwood wisdom2 console clipped onto a retractor reel at the bottom of my BC).

I don't ever truly equalize. It's kind of hard to explain but I can basically "feel" the air inside of my ear and I have control over it...I can move air through my ear without having to actually do anything (e.g. no jaw wiggling, nose pinching etc.)

As far as using alum80 for a deep dive, keep in mind that that was an accident. I had intended for this to be a 65ft dive, not a 136ft dive. This is not a mistake I will make again, and should I at some point PLAN to go deeper than 100ft I will absolutely invest in a bigger pony and a bigger main cylinder. Also, I checked my psi frequently while at depth (about every 30 seconds given my inexperience at that depth) and decided to ascend with a minimum of 1500psi. I started to realize how quickly the air was going, plus it dawned on me that I was doing something pretty stupid by being there at all, so at 1700psi I headed up.

As far as rethinking solo diving, I appreciate the concern but it ain't gonna happen. I realize I don't have a lot of dives, but they are all in limited vis, surgy conditions, surf etc. and 60 of them are solo.

 

[lamont]

I don't ever truly equalize. It's kind of hard to explain but I can basically "feel" the air inside of my ear and I have control over it...I can move air through my ear without having to actually do anything (e.g. no jaw wiggling, nose pinching etc.)

yeah, you equalize, you just have good ears, and can do it with a little gentle positive pressure on your eustacian tubes. you can still track when this happening and how much if you stay conscious of it. the air to equalize your ears at 136 ft didn't get there by magic, you just weren't staying aware of it.

As far as using alum80 for a deep dive, keep in mind that that was an accident. I had intended for this to be a 65ft dive, not a 136ft dive. This is not a mistake I will make again, and should I at some point PLAN to go deeper than 100ft I will absolutely invest in a bigger pony and a bigger main cylinder. Also, I checked my psi frequently while at depth (about every 30 seconds given my inexperience at that depth) and decided to ascend with a minimum of 1500psi. I started to realize how quickly the air was going, plus it dawned on me that I was doing something pretty stupid by being there at all, so at 1700psi I headed up.

you were also quite narc'd and stupid and didn't realize it.

narcosis isn't like alcohol intoxication, it starts with your short term memory and then starts to knock out your higher reasoning with only a little of the giddiness and lack of coordination of alcohol. by the time that you've hit 'laughing gas' levels of intoxication, you have actually been impaired at much shallower depths.

 

[The Chairman]

Thanks for checking your gauges often. That's really saved your butt. Checking depth and then checking air frequently will help you to negotiate these mistakes. It is my opinion that complacency is the biggest enemy we have underwater and I have heard too many divers pontificate how they don't need to check their gauges often.