arrived to a missed T: what to do next

[Underwater Tourist]

When I was doing full cave 1 year ago, I missed a T leading the dive in.

It was a hidden T that I was not warned about. The reason the instructor decided not to warn me about it, is because my course was going great without any major hiccups and the instructor wanted to show how easy it is to blow pass a T. I also mentioned in the class that the only thing I was worried in cave diving is making a navigational error. Not warning me about that T was the right way to do the course, and I am glad it went that way.

For those wondering, the T I missed is the first T you encounter if you dive Luke's Hope cenote in Mexico and take a hidden jump at the very beginning of the dive to the left to the Room of Tears. The T is some-what hidden behind a curve of the rock, the rock is also white and matches with the white line. And right before the T, you have a 2m vertical drop, so after you dropped you are busy adjusting buoyancy, which makes it easy to miss the some-what hidden T.

As a result of that mistake, I came up with a protocol for myself what to do if I ever arrive to a missed T. It's not rocket science, but I am sharing in case anyone has any ideas how to improve it.


So when you arrive to a missed T, there are two options. #1 You missed it on the way in #2 you missed it on the way out.

I think scenario #2 can be excluded because missing a T on the way out is super unrealistic because it would have been marked with your and your buddies rems on the way in. You really have to be mega distracted to miss a T marked with two giant pieces of plastic that are also probably in different colours. Just too unrealistic.

Which leaves option #1 as the most plausible. So now you have to determine which way is out, left or right. There aren’t many things you can do, but I came up with two.

First, you should have a sense of direction where the exit is (or a compass bearing). Like I know that it’s somewhere to the left, so T-left might be the best way. Second, you probably missed the T because it was hidden. So go on one side of the T and see if it looks at all hidden, and then repeat it on the other side. Ideally you want to have your directional bias (for example go left) be confirmed by the hidden check (so you go left, look backwards, and the T does look hidden). Obviously if you get conflicting conclusions then you have to make a judgment call.

Now there is a bonus step if you are lucky. In the real world, in MX there is an event that happens roughly every 10 mins (do a jump, drop a stage, mark a T, etc). If that was the case during the dive, then you have just enough gas to check both sides of the unmarked T.

If you are diving correctly then you should have at least 140bar left (in reality more because the way out is faster + you don’t spend time on jumps etc). So 140bar at 15meters = 40min of gas with 15L/min consumption. Let’s remove 10 min due to stress, so we have 30min worth of gas. This should be enough to go on wrong side of the T, realize you didn’t reach your “event”, turn back and swim out. Will you be sucking your last bar as you exit? Yes, but at least there is a real chance of making it out. The key is relaxed breathing rate of course, and swimming as close to the ceiling of the cave as possible to reduce gas consumption.


A few things to note:
-it is for MX specifically
-only works if you are diving properly (slower speed in, faster out)
-you time your "events" (made a jump 10min into the dive, dropped a stage at 20min, 25 min made a T-left, etc)
-didnt make other mistakes (for example arriving to an unmarked T not because you missed it, but because you made a visual jump without realizing it)

 

[Norwegian Cave Diver]

I have been from Car Wash to Room of Tears and also from Luke’s Hope. You must look at all tie offs. On a left or right corner - don’t cut that corner. Look at them all. Helps to remember the map and have it drawn in your wet notes. The map in your wet notes should be to scale. I have some that I created by scanning them and printing it off in sections in a size the same as my wet notes page. Then put that primed version behind a singe sheet of wet notes and against a window. It shine thru and I copy that image to my wet notes exactly as the map shows. You should know there are different routes/jumps/T’s and be looking for them. And the basic compass direction in and out. Two German cave divers passed away in Kalimba with most likely a navigation error. They chose to exit in the opposite direction of their stage tanks because they knew of another exit and thought it should be quicker to go that way. It is important to know - where am I? If you have a map to study then you may know what to expect… first marker will be a jump right. Then another jump right etc. then look for that as you dive.

Here is a link to cave maps in Quintana Roo…

Quintana Roo cave maps

Now go look at Mayan Blue. There are 3 listed. Look at the one with “lines”. Print it off. Study it. Put it in your wet notes. Dive it.

I will be back October 19th for a month. If your down there we can go cave diving together if your interested.

 

[steinbil]

If you are diving correctly then you should have at least 140bar left (in reality more because the way out is faster + you don’t spend time on jumps etc). So 140bar at 15meters = 40min of gas with 15L/min consumption. Let’s remove 10 min due to stress, so we have 30min worth of gas.

This part is very confusing. How are you arriving at these numbers?

15L x 40min x 2.5ATA = 1500L / 140bars = 10.7L

Are you diving a single 80 or something? Also estimating 25% increase in breathing rate when lost in a cave - is that not a tad optimistic?

 

[rddvet]

Your assumption that missing a t on the way out is harder is not accurate at all. Maybe in that particular area of Carwash it is, but it isn't an accurate generaliry. I have written a report here years back about missing a t in Ressel in France. I won't go into a full detailed story, but I'll give a synopsis. Firstly, caves in France are like the wild west. There were historically line wars between the regular cave divers and the French speleo guys that only care about cave diving to get to sumps. The lines in French caves are often confusing, poorly setup, and god only knows what kind of line you'll have. I've seen everything from normal line to 50 colors of line on one line, to actual wire line.
Anyway when you enter Ressel, within the first 5-10 minutes there is a t that goes to a high and low gallery line. These then meet up a few hundred feet back (this is all from memory, not looking at wet notes). Where the lines meet back up the line is behind a rock on the upper gallery side. At that time, the line coming from the lower gallery line to the t was yellow-green. The lines make more of a Y than a T and its wide cave so you can be following the line back out and end up on either side of the T when you arrive at it. In our case, we were on the lower gallery side which means you miss the T if you don't look behind the rock. On our way out we were more to the lower side, but the line that t's up to the rock was 3 different colors of line and looked more like a jump. We both made the mental error of assuming it was a jump and continuing on, missing the hidden t. About halfway through the area I knew we were on the wrong line, and made the unwise choice to not tell my buddy (my wife) because I knew we'd be back to our markers on the first t soon. About the time I realized it, she did too. Unfortunately she half ass looked at the map and didn't know where we were. She didn't panic but was really freaked the f out. She wrote "R we going wrong way" in very nervous handwriting in her wetnotes. I wrote an explanation and we exited safely but with thoroughly tightened butt holes.
My wife and I are very conservative cave divers. That incident made us even more conservative, and we learned alot from it. I still have the wetnote framed above our compressor in the garage as a reminder to take it slow and easy.

 

[rddvet]

I have been from Car Wash to Room of Tears and also from Luke’s Hope. You must look at all tie offs. On a left or right corner - don’t cut that corner. Look at them all. Helps to remember the map and have it drawn in your wet notes. The map in your wet notes should be to scale. I have some that I created by scanning them and printing it off in sections in a size the same as my wet notes page. Then put that primed version behind a singe sheet of wet notes and against a window. It shine thru and I copy that image to my wet notes exactly as the map shows. You should know there are different routes/jumps/T’s and be looking for them. And the basic compass direction in and out. Two German cave divers passed away in Kalimba with most likely a navigation error. They chose to exit in the opposite direction of their stage tanks because they knew of another exit and thought it should be quicker to go that way. It is important to know - where am I? If you have a map to study then you may know what to expect… first marker will be a jump right. Then another jump right etc. then look for that as you dive.

Here is a link to cave maps in Quintana Roo…

Quintana Roo cave maps

Now go look at Mayan Blue. There are 3 listed. Look at the one with “lines”. Print it off. Study it. Put it in your wet notes. Dive it.

I will be back October 19th for a month. If your down there we can go cave diving together if your interested.

As a newer cave diver this is what I did to learn Ginnie. I have a digital copy of the map and I will print the section of interest and laminate. If I was diving to a new area it would be in my wetnotes to reference. I rarely used it, but it was nice to have.

 

[berndo]

The lines make more of a Y than a T and its wide cave so you can be following the line back out and end up on either side of the T when you arrive at it. In our case, we were on the lower gallery side which means you miss the T if you don't look behind the rock.

You mean the line that goes almost straight up shortly before the cave bends to the left and to the shaft? Was this the first dive in Ressel? Ressel's got pretty good line compared to some other caves in the area.

I can see how you can swim past that but at least you probably still know where you are, if you've been diving there a couple of times before. In the more maze like cave that you're not really familiar with it's more of an issue or when viz really suck. I almost sh_t myself one time in in a 100-T-cave in Spain... and one time I ended up on a parallele line without noticing and it just ended... that really sucked. Was really bad viz in Cabouy. I hate when there is parallele line in a cave.

I was taught in cave class only to do one new jump or side tunnel per dive in a new cave so it's easier to keep track of where you are. So, first dive only on the main line, second one jump/ side tunnel etc. I still stick with that unless I dive with a guide.
I know not everybody was taught this but I think it's a very good strategy.
relying on maps can be an issue... many maps aren't that great.

 

[Guille G]

All responses show how important taking detailed notes as you go is. If you have good details on time, marker and directions then you should be able to work out what you should find 10-15 minutes down the “right” path, then make a judgement call, look for it and if you don’t reach it, head back.

I never missed a T (yet, fingers crossed, etc) but once reached an unexpected end of line. I was uneasy heading back until we saw our cookies on a T. Non-divers ask about tight spaces or darkness when they hear about caves, but an unmarked T when heading out would be the scariest **** ever.

 

[rddvet]

You mean the line that goes almost straight up shortly before the cave bends to the left and to the shaft? Was this the first dive in Ressel? Ressel's got pretty good line compared to some other caves in the area.

I can see how you can swim past that but at least you probably still know where you are, if you've been diving there a couple of times before.

I've attached a photo where I circled the T I'm talking about. I don't remember it being the one that goes straight up/down. I think that's further in. I can't say for certain as it's been about 6-7 years since I've been back in Ressel.
Anyway, this was our first trip to France about 11-12 years ago when we were only 4 months out of Cave 1. We had never dove any caves other than Florida (and at that point only fairly low penetration in the tourist caves), and had never dove in any water below 68 degrees. We had done one dive in Ressel two days earlier and hadn't made it to that second t as we weren't adapting to the cold well. We were attempting to be conservative and learn the cave before going too far in, but still had the missed t issue. I chalk it up to inexperience, nervousness of being in a new cave in a new country, a little mental lagging from not being used to the cold (I was only wearing a 3mil hood according to my notes), my wife not studying the maps as much as she should have since she was busy enjoying France, and just simply missing it because we were looking all over the cave in awe. We learned alot from it and it's kept us very conservative still and made us huge fans of very slow progressive penetration.
I was told by Harald from plongee de souterraine that around that time there was some really big battling back and forth with the different groups over the lines so the lines were constantly changing and moving. We did two more dives in Ressel after that missed t. I left a cookie at a t as a reference one afternoon. The next am it wasn't there and the snoopy loop that was near the t was changed to a line wrap. We saw 3 different line changes in the week we were in the area. I've been told its settled down some now. Our second trip we had no issue and the lines had actually improved some.
I attached the note my wife wrote to me. Even underwater her hadnwriting is good. The scribbly writing isn't like her at all and is a strong reminder to not let that sh-t happen again.

 

[grassgreen]

Which leaves option #1 as the most plausible. So now you have to determine which way is out, left or right. There aren’t many things you can do, but I came up with two.

First, you should have a sense of direction where the exit is (or a compass bearing). Like I know that it’s somewhere to the left, so T-left might be the best way. Second, you probably missed the T because it was hidden. So go on one side of the T and see if it looks at all hidden, and then repeat it on the other side. Ideally you want to have your directional bias (for example go left) be confirmed by the hidden check (so you go left, look backwards, and the T does look hidden). Obviously if you get conflicting conclusions then you have to make a judgment call.


As soon as you notice you have missed a T on the way out, you should place an arrow on the line you are on . Then make your best judgement call of which of the other 2 lines to take....if you chose the wrong one, realise that and turn around, youll get back to the arrow you just left then you will only have 1 option left, the correct line to exit...That arrow you just put will stop you accidentally going that wrong way..

 

[Underwater Tourist]

I have been from Car Wash to Room of Tears and also from Luke’s Hope. You must look at all tie offs. On a left or right corner - don’t cut that corner.

I will be back October 19th for a month. If your down there we can go cave diving together if your interested.

Yes in MX its especially important to examine tieoffs and swim near the line.
Oct 19 sounds great, I alway go early November just as the rainy season comes to an end and the main wave of tourist hasnt arrived.

And also about diving the plan, as I was exiting that dive, I knew that I missed a T because the dive plan was to make two Ts, and when I turned the dive, we only reached one T. So I was 100% certain that I missed a T and was expecting it.

This part is very confusing. How are you arriving at these numbers?

15L x 40min x 2.5ATA = 1500L / 140bars = 10.7L

Are you diving a single 80 or something? Also estimating 25% increase in breathing rate when lost in a cave - is that not a tad optimistic?

I meant you have 70bar left in each of the AL11 tanks so 140 total.
So (140bar * 11L) / (15L/min * 2.5 atmosph) = 40min of gas

Your assumption that missing a t on the way out is harder is not accurate at all. Maybe in that particular area of Carwash it is, but it isn't an accurate generaliry. [....] Firstly, caves in France are like the wild west.

I think the assumptions work for MX in general not just Carwash. But yes, the assumptions are completely wrong if we talk about any other cave destination country. 100% of my cave diving is in MX, so I came up with this "missing T protocol" for MX specifically.

You posted the report on SB right? I am 99% sure I read it several years back probably even before I did cavern. Everyone always says that French caves are.. you know, French

I never missed a T (yet, fingers crossed, etc) but once reached an unexpected end of line.

There are like a billion of hidden Ts in MX probably. I only made 3 trips, and can already come up with at least 2. Just take a guide and ask him/her to mix in some routes with hidden Ts and lead the dive.