is Sidemount diving more safe?

[Stunni]

thx. found it... seems no actual 2023..

DAN Dispatch: New Annual Diving Report Available

THE NEWEST EDITION OF DAN’S ANNUAL DIVING REPORT IS NOW AVAILABLE. While the release of the 2020 report was delayed, it offers fascinating insights, statistics, and case summaries of recreational dive incidents and fatalities that occurred in 2018.

dan.org

 

[34109411]

it alway 1 or 2 years old time to collect data, analyze them and publish.

 

[SlugLife]

btw, sidemountainians do better kissing...

One under each shoulder.

 

[billgraham]

hey, thats really cunning... how much space between the rings? must look like you fished them like a line fisher

I guess it depends how high the boat is out of the water but you want one tank to come over the rail while the other(s) are still in the water, best if someone helps you unclip them. It's typically much nicer to do deco on the equipment line rather than the anchor line. Of course this involves swimming from one to the other, which shouldn't be a problem if you're doing this type of diving but a lot of people seem terrified to let go of the downline. The downside to this is that it's another line in the water which must be pulled up before the boat gets put in gear!

 

[SlugLife]

hey, thats really cunning... how much space between the rings? must look like you fished them like a line fisher

I've found it's useful to consider both the height of the tank, and the distance you have to lift the tank out of the water.

Something else you can do, is use some line and a bolt-snap, which is affixed to the tank-harness. Wrap the cord around the bolt-snap, and then clip the end, so it doesn't unravel, and also clip that bolt-snap to a d-ring or other bolt-snap on the tank-harness. (I should probably just take a photo, because this description is terrible) Doing this gives you the option to clip your tank to a boat, ladder, or railing at the end of your dive, and not need to leave a cord dangling off the rear of the boat.

 

[John C. Ratliff]

I *am* a research statistician, with an expertise in experimental design. SlugLife is correct here; as multiple folks have pointed out, there's not a sufficient sample size to draw any reasonable conclusions, and the list of potential confounds is so long that even if you were to find an effect, it could be due to any number of causes - some of which we can measure and (partially) control for, and some of which we can't.

The only real way to know would be to assemble a very very large group (you'd need a huge sample given the low baserate of deaths/incidents) of divers trained in both SM and BM, who would be willing to be randomly assigned by a researcher to do their dives in SM vs BM for a given stretch of time. (You could also randomly assign per dive, which would increase statistical power, but also add enormous logistical complexity). Then see whether more of the divers in the BM condition have accidents/incidents than those in the SM condition. I highly doubt any ethics board would even approve that study (i.e., could end up randomly assigning someone to dive a SM-only cave in BM), and even if they did, there's almost certainly not any way to get the sample size/level of compliance you'd need for causal inference.

Some questions are just not very amenable to being answered empirically; a similar problem exists (for example) for whether any level of diving is safe during pregnancy. The number of women diving while pregnant is so low, and complications rare enough, that the published literature has more or less concluded that it's unlikely we will ever have the sample size to allow us to statistically determine the risk (and whether any safe limits exist). The best we can do is draw on animal studies, and our theoretical knowledge of physiology and how diving could affect that in pregnancy. The same approach is the best that can be taken here; there may be theoretical arguments for SM vs BM, but it's unlikely we'll ever have sufficient data to test those arguments empirically.

And, as I like to tell my students: the plural of anecdote is not "data".

I have decades of experience in the occupational health and safety field, and a MSPH degree in Industrial Hygiene. There is one way that a sample could be gained, but it would require a new way of tracking diving and logging the diving experience.

Years ago, I started hand writing my dive log (which more recently I have not done as readily as before). But what I found is that if I set up a special section of my dive log to log "Special Problems and Solutions," I could track the small things that happen each dive that go wrong, and see trends in my own diving.

If this concept could be used on a larger study, getting, say, 100 side mount divers to track "Special Problems and Solutions," and 100 back mount divers to do the same over a year-long, or say 100 dive long, period of time, then take these logs and track the types of problems each diving method experienced, I suspect we would find some interesting aspect to both types of diving that no one has logged before.

Below is one of my dive logs, which has that category.

SeaRat

 

[34109411]

I have decades of experience in the occupational health and safety field, and a MSPH degree in Industrial Hygiene. There is one way that a sample could be gained, but it would require a new way of tracking diving and logging the diving experience.

Years ago, I started hand writing my dive log (which more recently I have not done as readily as before). But what I found is that if I set up a special section of my dive log to log "Special Problems and Solutions," I could track the small things that happen each dive that go wrong, and see trends in my own diving.

If this concept could be used on a larger study, getting, say, 100 side mount divers to track "Special Problems and Solutions," and 100 back mount divers to do the same over a year-long, or say 100 dive long, period of time, then take these logs and track the types of problems each diving method experienced, I suspect we would find some interesting aspect to both types of diving that no one has logged before.

Below is one of my dive logs, which has that category.

SeaRat

wow much dedication !

 

[Norwegian Cave Diver]

I have decades of experience in the occupational health and safety field, and a MSPH degree in Industrial Hygiene. There is one way that a sample could be gained, but it would require a new way of tracking diving and logging the diving experience.

Years ago, I started hand writing my dive log (which more recently I have not done as readily as before). But what I found is that if I set up a special section of my dive log to log "Special Problems and Solutions," I could track the small things that happen each dive that go wrong, and see trends in my own diving.

If this concept could be used on a larger study, getting, say, 100 side mount divers to track "Special Problems and Solutions," and 100 back mount divers to do the same over a year-long, or say 100 dive long, period of time, then take these logs and track the types of problems each diving method experienced, I suspect we would find some interesting aspect to both types of diving that no one has logged before.

Below is one of my dive logs, which has that category.

SeaRat

What would you consider to be "Special Problems and Solutions"?
As a sidemount diver in open water - vs - Sidemount diver in a cave - vs - sidemount diver in a wreck.
The Special Problems list will be different.

 

[John C. Ratliff]

What would you consider to be "Special Problems and Solutions"?
As a sidemount diver in open water - vs - Sidemount diver in a cave - vs - sidemount diver in a wreck.
The Special Problems list will be different.

I don't over think "Special Problems and Solutions." It can be anything that interfered with the dive in some way. Years ago, I noted in my dive logs "I got cold," and "I'm freezing," on several dives. I finally decided that I needed a dry suit.

On 6-11-2011 I wrote up a dive. It is extensive enough that I don't want to put everything here, but I had the "Special Problems and Solutions" section filled out. Here's what I wrote:

1. I was really glad I had dived today. I almost did not, as the conditions were what I considered marginal for diving (weather, visibility, current).

1. I did want to test my hybrid Healthways SCUBA regulator, as it had a duckbill in the exhaust. I had tested it during the surface dive, and found no water penetrated into the exhaust hose like it did without the duckbill. I had the original diaphragm in it too, which did not seal as well as the glove material of nitril I had used before. But it is probably stronger, and did do well. The exhalation was ever-so-slightly easier when I was right-side down, probably because a slight amount of water leaked into the chamber between the duckbill and the exhaust diaphragm.
2. There was water inside the regulator, which means that it probably leaked in through the diaphragm seal. I used a different ring than the original one, thinking it would be better, but apparently it was not.
3. The Scubapro AIR I is an awesome regulator. I used it just after seeing the sturgeon, and that is a wonderful regulator.
4. The SeawiscopeEY enabled me to get within a foot of the lampreys as they were mating and watch it very, very closely. It was absolutely amazing to see. Using a quiet double hose regulator helped this too; I don’t think I could have made these observations at this distance with a single hose regulator.
5. My wet suit is getting very old, beat up, stiff and needing to be replaced.
6. My Para-Sea BC worked extremely well, and I had the modified military harness on the tanks, which was very comfortable. I had a USD backpack on this set last year, and getting out caused me to get a muscle strain as the full weight of the cylinders was on the one portion of my lower back where the backpack hit. I probably had the chest strap too tight, as I needed to loosen it when walking back to the car.
7. Oh, how I wished I had carried my camera! But it was the first dive, in dark waters with a high current. My camera is so bulky that it would have been difficult to bring, but I could have gotten some really unique photos of lampreys mating. I probably would not have gotten anything of the sturgeon thought, due to the startle factor.

Note that last entry. Here are some of my observations from that dive:

...I swam up the gravel bank from about 15 feet depth to about 10 feet depth, nearing the bottom portion of this eddy but where there was still a downstream current. There I saw two more lampreys, which were joined by this third one, on the bottom holding onto stones in their mouths. Then they curled around each other, and began mating. I reached up to my mask and brought the SeawiscopeEY down in position on my mask. This is a double-lens device that allows very close focusing and observations. With it down, and the two lampreys in a mating position (one male attached itself to the female’s head, and circled her body with his), I watched in amazement as they convulsed in a mating orgasm, and eggs and sperm came out. After a moment, the male released his grip on her head, and the three lampreys began moving stones over the site. At first. It was small stones being moved out, then large stones were moved on top. They kept moving the stones in the river, and the large ones were bigger than my fist. One lamprey would cling to the stone with his/her mouth, then with body undulations try to displace it from the bottom. The larger stones were moved over the area of the eggs, which were sticking to the rocks on the bottom. Some had drifted back in the current too.

This process was repeated at least five times while I watched during the next 20 minutes. The male would grab the head of the female, wrap his body around the female and they would release sperm and eggs in what could only be described as a body convulsion, a fast-frequency twitching of the whole lower bodies of the two fish. This would be followed by several minutes of moving stones on the bottom. This was a cooperative effort by three lampreys. At one point, the dominant male tried mating with the female, and because the other male was along-side could only wrap his body around the both of them. That did not work, so he would change his body position slightly and try again. Finally, and only after he had successfully wrapped his body only around her, the mating commenced again.

This mating activity of the lampreys was fascinating to watch. Toward the end of my observations, the other male tried to mate with this female, and a fight ensued. The dominant male attached to the other male with his mouth, and swam him away. He returned, and the fight ensued again. Eventually, only the female and the dominant male were there.

Because of that, I decided to dive with my GoPro camera on June 11th and 17, 2017 to record what I had seen on that 2011 dive. Sometimes tracking things allows me to go back and decide for the future dive what to do...

I tried on a subsequent dive to get photos of those lampreys, but was unsuccessful with my Canon New F-1 in a Ikelite housing because of its bulk and the currents to get to the same area. Several years later, I was able to follow up with a GoPro camera and record the lampreys spawning habits. That's the thing about writing down special problems and solutions; you can go back and see what you wanted to do.


SeaRat

 

[Stunni]