Two lessons learned in one season... Hmmm...

[Reg Braithwaite]

If you were already close enough to your No Deco limit that your ascent did not "outrun" it, then your situation is the result (going into deco)... I now do not push my limits like that week (I also started diving Nitrox ).

Yeah, having checked the log:

Started the ascent: 20 min
mid-water stop: 25 min
ASC TIME warning: 27 minutes, demanded four minutes of ascent
ended dive: 34 minutes

ANd yes, I am qualified for Nitrox but was diving Air. Perhaps that's another Hmmm... Maybe I should have chosen Nitrox on a day when There were risk factors involved?

 

[Ayisha]

Toronto is 3 1/2 hours' drive from Brockville, so local dive shops usually do a weekend charter as two dives on Saturday afternoon, camp or hotel stay Saturday night in Brockville, two dives Sunday morning, and drive back Sunday afternoon.

Since I wanted to maximize my fun, instead of going with a local group, I called an operator in Brockville and signed up as a "walk on" for two dives Saturday morning departing at 9:00 and two more dives Saturday afternoon, departing at 2:00, then drove back last night.

So, was I really in my best condition to dive having woken up at 04:45? Was I fully alert on my fourth dive on the same day?

So now you know why we go to Brockville on Friday evening, do 2 dives Saturday, stay Saturday evg, and then 2 dives Sunday and then drive back to T.O. It's just so much more relaxing and you begin the dives alert and fresh. I would not want to do that schedule you had - the drive home alone would be brutal!

I understand that it is hard to get away for the whole weekend because you have a wife and children, but if you only do this once in a while, your family should hopefully be ok with it. Brockville is a very family friendly place - you could bring your family. You and your wife could take turns diving or possibly find a babysitter for during the dives. You could network with other local people so that you have familiar buddies to dive with in Brockville or anywhere else. Some of the members of the local group might have been more fun and could possibly become your regular buddies.

Failing those ideas, you could drive up on a Saturday, do ONLY 2 dives, and then drive back Saturday afternoon/evening, without spending a night there. It's still a long day, but some people do it. That's a little less gruelling than what you went through.

Most of the wrecks chartered by boat in Brockville are pretty deep. The Daryaw and most of the others can have some pretty fast current. The conditions are for Advanced, experienced divers and therefore can require your full alertness and energy. You were lucky you did the Drift adventure dive in your Advanced - it is not required - and some divers are unprepared for those kinds of drift dives.

Regarding the profiles, it's already been noted by other posters. Just remember to read your gauges often, keep a healthy buffer from your NDL's, and keep enough of a reserve to bring you AND your buddy to the surface safely. Especially since some of this diving is done in the shipping channel, it MUST be treated as an overhead environment where you must ascend where you began, on the line. This makes having an appropriate reserve extremely important since you cannot ascend safely anywhere and gas planning is paramount.

However, Brockville is also incredibly fun and has amazing shipwrecks! Every other year, the visibility has been excellent - 50 - 100 feet - and it's warm all summer. This year, visibility has been poor probably due to all the rain. Go with the right buddy, relax, and hopefully have more fun next time!

 

[dave4868]

Well perhaps, but looking back at it, maybe it's reasonable that I didn't notice Mr. Doubles bailing as I descended from the rudder to the deck. The entire wreck lies in its own narrow groove, with walls on each side, the next time I am out there I will try to figure out if it's possible to get down there while simultaneously watching two buddies.

When I buddy dive with strangers, I find it helps to actually discuss the basics of how buddy contact will be maintained, such as the buddy staying nearly abreast of the leader and well within the visibility limit, and how often the leader and follower will glance toward the other (every ten seconds works pretty well in 20-30' vis) and what each will do if contact is briefly lost and agree that communication is necessary before intentional separation.

Even though it's so basic, people get different ideas of how to maintain contact, especially when strangers are thrust together on a more challenging dive.

Yeah, I noticed another comment that you can't get into deco on the ascent. I am going to replay the log and report back, I thought it went into deco as I did a mid-water stop, but it is difficult for me to claim that I made mistakes and simultaneously claim that I am 100% sure I didn't go into deco before the ascent.

Seems to me that an unusually slow ascent or sawtooth ascent could get the computer to call for a ceiling.

What I can say for a fact is that I am going to pay a lot more attention to the cumulative nitrogen bar on the LHS of the Gecko's dial in future.

That's what I typically do, especially on repetitive dives and certainly if I'm getting close to deco. Sometimes you can tell your buddy that you'll stay 20' higher than him to lessen your nitrogen while finishing the dive or just ask him to follow you up.

700 PSI at the surface.

Well, that's good. You probably could have spent 20 minutes or more at 15', if required. You did very well compared to me, since I tend to be a little nonchalant and push the limits....

You deserve a lot of credit for your honest and insightful post-dive analysis.

Dave C

 

[Ayisha]

ASC TIME warning: 27 minutes, demanded four minutes of ascent

What does "ASC TIME" mean?
Does it mean that you were ascending too fast?

You say that it demanded 4 minutes of ascent - What does that mean? You had to slow down your ascent or you had to do an extended safety stop (due to fast ascent or going into NDL)?

Sorry, I don't use a Suunto. I use an air-integrated Sherwood Wisdom and it tells me the number of safe minutes left based on a combination of NDL and remaining gas.

If my computer gives me an Ascent warning, it is specifically warning me about the rate of ascent and will tell me to slow down.

 

[Reg Braithwaite]

What does "ASC TIME" mean?
Does it mean that you were ascending too fast?

You say that it demanded 4 minutes of ascent - What does that mean? You had to slow down your ascent or you had to do an extended safety stop (due to fast ascent or going into NDL)?

Sorry, I don't use a Suunto. I use an air-integrated Sherwood Wisdom and it tells me the number of safe minutes left based on a combination of NDL and remaining gas.

If my computer gives me an Ascent warning, it is specifically warning me about the rate of ascent and will tell me to slow down.

As I understand it...

1. It shows you the number of minutes left before going into deco
2. If you are ascending too fast, you get a SLOW warning
3. If you aren't in deco but a close to it, you get a STOP warning, meaning the safety stop is not optional
4. the ASC TIME warning means you are in deco and you need to have a slow ascent. It shows the number of minutes you need to devote to your ascent. That number rises if you ignore the warning and do not ascend immediately.

Things appear to get complicated with ASC TIME. There's an up arrow telling you to rise, and once you reach a certain level it goes away and the number of minutes starts counting down. If you go too high you get a down arrow.

So, it was not an ascending too fast warning. Actually, I did get one of those but in an unusual way: when we reached the bow of the wreck we groveled on the bottom and I signed that we were going up and over the top. Pisces mimicked my hand gestures, and then we rose and flew the length of the ship.

In rising to the keel, the slow warning came on. I actually didn't see it, I wasn't paying attention to the computer at that moment. In future I should remember that an ascent is an ascent is an ascent.

 

[PR_SMITH]

Well, here's my *second* lesson learned. As the title says, "hmmm..."


Toronto is 3 1/2 hours' drive from Brockville, so local dive shops usually do a weekend charter as two dives on Saturday afternoon, camp or hotel stay Saturday night in Brockville, two dives Sunday morning, and drive back Sunday afternoon.

Since I wanted to maximize my fun, instead of going with a local group, I called an operator in Brockville and signed up as a "walk on" for two dives Saturday morning departing at 9:00 and two more dives Saturday afternoon, departing at 2:00, then drove back last night.

So, was I really in my best condition to dive having woken up at 04:45? Was I fully alert on my fourth dive on the same day?

I was booked and paid-up for a dive charter this weekend; here's an excerpt from an email to a buddy explaining why I bailed:

"As it turns out, I didn't get Kingston either. I had already paid, and
was hoping to leave work at 3pm Friday to get there in time for a good nights
sleep, but didn't get out of work until 7, then had to get my gear ready,
hook up the trailer, yada, yada. Got 5 mins down the road, lost an
hour in a road block, 'cause some poor bugger drove his car into a
rock-cut. Then drove another half hour and decided that I wouldn't get
to Kingston until 2 am at the rate I was going, not to mention the
foggy roads. Figured no point in going on a dive when you are exhausted before you start. So I aborted the mission, came home had a good nights sleep, and in the morning
connected with 2 dive buddies, went to Clear Lake(25 mins from my place). Anyway, we got 2 easy shore dives in."

My point is that my getting to the dive in good shape, well-rested, etc, went off the rails, so I aborted the plan and made a new one.

Be kind to yourself and family and don't do 4 dives, with strangers, when you are already self-handicapped by arriving tired. I respect myself enough, AND those I might dive with, to not be in a tired condition, where I KNOW that I won't be physically/mentally A1. I often regret decisions made whilst tired.

I think it's commendable that you have posted here for comments; that shows maturity and willingness to learn. Good for you.

 

[dumpsterDiver]

I've had computers go into deco simply by doing a deep stop which slows the ascent more than the computer "would like". Once it goes into deco (on say the 4th dive) it will give you a nice little stop. People don't get bent by diving too long, they get bent by coming up too fast.

Going into deco is not that big of a deal especially if it is caused by an extra minute at 50 feet on ascent. If it were me, and I got a mandatory deco on the 4th air dive of the day, I would do my deco stop and then add a good 3 minutes of safety stop. Seems like people do safety stops for 5 minutes sometimes, but when they get 3-4 minutes of deco they seem to want to clear the deco and do only 1-2 minutes more for safety.

It's been my practice to do at least 3 minutes of safety stop AFTER the deco is clear.

 

[TSandM]

First of all, huge kudos to you for posting this and exposing yourself to criticism, so that all of us can learn from your experiences. I've done the same thing, and it isn't easy to take the heat.

Dives can be divided into phases. You have descent, stabilization, bottom time, and ascent. The times when things are most fragile are the times of transition. Descents and ascents are definitely transitions, and they're times when people are going to have problems. On descent, they may have a camera flood, or discover their ears won't clear, or that they've forgotten to open the valve on their argon bottle. On ascent, they may be having buoyancy problems, trouble venting, or a reverse block. These are the times when the team should be the closest together, and paying the most attention. This is one of the reasons I don't do ballistic descents; we almost always pause at 10 or 20 feet and quickly eyeball one another, and make sure everybody's happy. Today, I had a buddy with significant ear problems; we had to go up a couple of times before she got everything sorted. But we never lost one another.

Regarding the deco, all I'll say is that there wasn't any planning going on here. Even if you dive your computer, you can put it in plan mode and simulate the dive you are going to do. That would have told you you were going to go into deco on that dive. Now, going into deco is not a sin, nor is it horribly dangerous . . . IF you are sure you have the gas to do the deco, and you have the skills to handle any problems that arise underwater while you are under a virtual ceiling.

I can tell you, from having taken two recreational triox classes (failed one, squeaked by the other) that managing all possible problems while in midwater is a major challenge. Saddling yourself with a decompression obligation while on a single tank, and with a fairly unknown buddy, is a recipe for an injury if anything goes wrong with your gear. If Pisces got his back to you and kicked your mask off, while you were doing that prolonged stop, would you be comfortable and stable? If one of you had had a freeflow, did the other have enough gas to supply both of you during the stop, and all the way to the surface?

These are the kinds of things that people learn when they set about to do mandatory decompression diving. It's harder than you think. Deco, on a single tank, with an unknown buddy, in midwater, is a set of risks I personally wouldn't undertake.

But everybody came home okay, and you have some food for thought. We learn very little from the dives that go absolutely as planned. Most of the time, we learn because we (or somebody else) screwed up. You're clearly really thinking about this; that's all that matters, in the end.

 

[Reg Braithwaite]

So now you know why we go to Brockville on Friday evening, do 2 dives Saturday, stay Saturday evg, and then 2 dives Sunday and then drive back to T.O. It's just so much more relaxing and you begin the dives alert and fresh. I would not want to do that schedule you had - the drive home alone would be brutal!

It does seem unlikely that I'm going to repeat this schedule! FWIW, I was considering hooking up with some Torontonians. Aquarius Scuba was running a group dive that exact same afternoon with the same dive operator. Alas, the were scheduled to do the Muscalonge and then the Lily Parsons.

Meanwhile, my morning walk-on was scheduled for the Gaskin and Lily Parsons, and I didn't want to do the Lily twice. Of all the wrecks on the river, that's probably the least interesting to do twice in one day.

So... I didn't hook up with Aquarius that time, although I have done group trips with AquaSub in Brockville and Aquarius in Tobermory when I could schedule a sleep-over. I'll try to do more trips with locals in the future.

Can you suggest any groups you like?

 

[PR_SMITH]

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