My lesson learned

[flots am]

He pointed out that the 220 ft reading was spurious and not a true depth.

Given that the computer recorded the correct depth at the surface, both before and after the dive, I'm inclined to go with the computer.

flots.

 

[Superlyte27]

I hate to agree with Flots, but I'm believing the computer more than the OP at this point.

 

[Hatul]

I hate to agree with Flots, but I'm believing the computer more than the OP at this point.

It's a possible interpretation, that he was so narked and not aware of the descent from 150 to 220 ft. There are two factors to consider: 1. the Redondo Canyon is not a wall but runs at down at something like 45 deg angle, so it's hard to avoid being aware of a slip of that depth. 2. the computer profile printout shows a max depth of 330 ft, which is unlikely.

 

[flots am]

It's a possible interpretation, that he was so narked and not aware of the descent from 150 to 220 ft. There are two factors to consider: 1. the Redondo Canyon is not a wall but runs at down at something like 45 deg angle, so it's hard to avoid being aware of a slip of that depth. 2. the computer profile printout shows a max depth of 330 ft, which is unlikely.

300' isn't hard to do once you have no idea what planet you're on.

Bad sensors are just bad. I've never heard of one that was off by more that 100% but still maintained zero-calibration.

flots.

 

[antattack]

You expected this would be a tough thread and you posted anyway.

It is much better to learn from the diver who made mistakes and lived to tell the tale than try to learn from a forensic report.

What you have done after this dive is important.

Thank you for taking the trouble to write this up. Thanks for engaging the community in a positive way and persevering in your quest to share and learn.

Now let's train, prepare our gear and plan some safe dives!

Rather than re-tell the story, I'm posting the link to my incident. There are three parts:

Part 1: Of Bikes and Bubbles: The Perfect Storm
Part 2: Of Bikes and Bubbles: The Storm Continues
Part 3: Of Bikes and Bubbles: It's Clearing, Somewhat

After further analysis, I was also given a great suggestion, should this ever happen again, keep going until you're at about 15' and just stay there until you run out of air.

Luckily, it's live and learn.

 

[Superlyte27]

It's a possible interpretation, that he was so narked and not aware of the descent from 150 to 220 ft. There are two factors to consider: 1. the Redondo Canyon is not a wall but runs at down at something like 45 deg angle, so it's hard to avoid being aware of a slip of that depth. 2. the computer profile printout shows a max depth of 330 ft, which is unlikely.

Do the math. How long does it take to get from 150' to the surface, and how much gas do you use, even with elevated sac rate. It just doesn't add up. And the diver hasn't told us how long it took him to surface. I'm guessing that was omitted on purpose. However, if you look at the computer profile, I infer that it's pretty much in line with the gas usage and time to surface. Of course I'm making some assumptions, like what his sac rate is, and what his ascent speed was based on what I've read, but none of that really matters now does it. Proper planning, gear, skills to do a dive like this could have avoided all of this even if the computer read the wrong depth the entire dive.

 

[racerfern]

It's a possible interpretation, that he was so narked and not aware of the descent from 150 to 220 ft. There are two factors to consider: 1. the Redondo Canyon is not a wall but runs at down at something like 45 deg angle, so it's hard to avoid being aware of a slip of that depth. 2. the computer profile printout shows a max depth of 330 ft, which is unlikely.

I will grant that I may have narced, probably was narced or definitely was narced. And that certainly affected my thinking process. I guess since my thinking and planning were so flawed it appears I was narced before I hit the water.

However, I am 100% sure I did not hit 220' or 330' ft. I was able to download the dive and I can email anyone that's interested the data as a csv or just about whatever format. Looking at the profile there are three things that stand out:

1) At the very start of the dive the graph shows an immediate drop to almost 160' even before I got to 30'. I was just beyond the end of the pier at Veterans Park and expected to drop into 60' of water. When this happened I didn't even notice since I was simply dropping slowly while looking down to make sure nothing dangerous was below me and looking waiting for other divers to descend. I settled on the bottom 56' and waited for a couple of minutes before starting my gradual descent. There were two things I stopped for. A dead shark at about 100' (only briefly) and some weird piece of pipe with some strange little fish in it whose name escapes me right now at about 136' more or less. Then I went to 150' looked around, gave three more kicks and glanced at my gauge.

2) That's where I saw 220 then 330. I immediately realized something was wrong and decided to turn around, end the dive and begin my gradual ascent on the same slope I followed down. On the graph you can see the sudden drop to just beyond 330' then back to about 70' where it starts to look like a normal dive profile.

3) The dive ended at about 33 minutes however, I never went back down. However the unit shows me underwater for the next 3 1/2 hours. That did not happen.

I am not posting this to show the failure of the computer, I am posting this to hopefully put to rest that on the "gentle" slope of Redondo Canyon there simply wasn't enough time to get to 220' never mind 330' unless I fell off a cliff and magically came back up within a minute or two at the most. I entered the water at 11:00AM, came up 33 minutes later. I had about a 10 minute or so it seemed swim back to the beach. I then sat on the beach and rested for a few minutes and walked toward the steps. My wife confirms she saw me walking on the beach just before 12:00 so I believe my times are correct.

There are two screenshots attached. The left one is the download from the computer software. I scrolled to where the data shows the drop from 153 to 330 and back to 113 all in the span of one minute.
The right screenshot is just a larger version of the profile as imported into ScuBase. FWIW the computer is set to record at its highest resolution which is 15 second intervals.

 

[Hatul]

I will grant that I may have narced, probably was narced or definitely was narced. And that certainly affected my thinking process. I guess since my thinking and planning were so flawed it appears I was narced before I hit the water.

However, I am 100% sure I did not hit 220' or 330' ft. I was able to download the dive and I can email anyone that's interested the data as a csv or just about whatever format. Looking at the profile there are three things that stand out:

1) At the very start of the dive the graph shows an immediate drop to almost 160' even before I got to 30'. I was just beyond the end of the pier at Veterans Park and expected to drop into 60' of water. When this happened I didn't even notice since I was simply dropping slowly while looking down to make sure nothing dangerous was below me and looking waiting for other divers to descend. I settled on the bottom 56' and waited for a couple of minutes before starting my gradual descent. There were two things I stopped for. A dead shark at about 100' (only briefly) and some weird piece of pipe with some strange little fish in it whose name escapes me right now at about 136' more or less. Then I went to 150' looked around, gave three more kicks and glanced at my gauge.

2) That's where I saw 220 then 330. I immediately realized something was wrong and decided to turn around, end the dive and begin my gradual ascent on the same slope I followed down. On the graph you can see the sudden drop to just beyond 330' then back to about 70' where it starts to look like a normal dive profile.

3) The dive ended at about 33 minutes however, I never went back down. However the unit shows me underwater for the next 3 1/2 hours. That did not happen.

I am not posting this to show the failure of the computer, I am posting this to hopefully put to rest that on the "gentle" slope of Redondo Canyon there simply wasn't enough time to get to 220' never mind 330' unless I fell off a cliff and magically came back up within a minute or two at the most. I entered the water at 11:00AM, came up 33 minutes later. I had about a 10 minute or so it seemed swim back to the beach. I then sat on the beach and rested for a few minutes and walked toward the steps. My wife confirms she saw me walking on the beach just before 12:00 so I believe my times are correct.

There are two screenshots attached. The left one is the download from the computer software. I scrolled to where the data shows the drop from 153 to 330 and back to 113 all in the span of one minute.
The right screenshot is just a larger version of the profile as imported into ScuBase. FWIW the computer is set to record at its highest resolution which is 15 second intervals.

View attachment 149370View attachment 149371

It does look like something wrong with the computer when you hit 150ft. It's really not possible to descend from 150 ft to 330 then back up to 60 ft all in 2.5 or so minutes.