Hacker News new | ask | show | jobs
by aksyn 2957 days ago
I got into diving a couple of years ago, and managed to combine the two passions - there's an Open Source diving computer[1], and it's fascinating to read through the source[2].

I was surprised on looking into it more that we're really just winging it algorithmically + safety margins, based on research done in the 60s. The empirical research basically consisted of the Navy et al. throwing people in at depth, and seeing what got them "bent".

Everybody's physiology is different though, and there are a large number of factors over-and-above that which affect whether you'll suffer Decompress Sickness (DCS).

Whilst there have been some iterations on Bühlmann[3] such as VPM-B[4] (which is based on bubble diameter vs. tissue compartment loading), the field is still lacking IMHO.

Not really through any fault of their own, it's just very difficult/expensive to peer into the body whilst they're down there to see what's going on, and it seems we'd need a large sample size due to individual physiology playing a part. Still, the algos seem to work... most of the time. Just don't drink too much alcohol, sleep well, hydrate. And do your stops! :)

Interestingly, saturation divers / Navy generally don't use a computer as the divemaster singularly plans the dives for the group with massive safety margins. As they're already saturated, they're generally not doing stops "outside" in the wet anyway. If they do have a computer, it will even have the tables/algos removed from it.

[1] https://heinrichsweikamp.com/

[2] https://bitbucket.org/heinrichsweikamp/ostc4/wiki/Home

[3] https://en.wikipedia.org/wiki/B%C3%BChlmann_decompression_al...

[4] https://en.wikipedia.org/wiki/Dive_computer#Algorithms

Edit: Formatting

1 comments

That dice computer looks great. Do you own one? Do like it?
I have both the OSTC4 and OSTC3 Plus. The screens are extremely visible underwater, with the OSTC4 having a better resolution and much larger screen (equivalent brightness). There are quite a few YouTube videos of other computers to compare - these stood out. As far as computers go, they have all the features needed (even up to tech). I find having a nice piece of technology on my wrist provides some intangible comfort, especially on Blackwater dives :) The screen is so vivid I even managed to spot a battery warning (forgot to charge it) on my buddies computer from distance!
Thanks. I have just started scuba diving and am looking at getting the ultra budget Cressi Leonardo Dive Computer. Is getting that a bad idea given I am just a newbie?
Buying a "starter" dive computer makes a lot of sense as many divers quit after a year or two. As your skills and interests progress, you can aways upgrade to a better one.

It's been a while since I bought my last dive computer, but looking at the spec for the Leonardo, it looks okay. Personally I'd prefer one that includes a stop timer, but that's not a show stopper. The ability to download your dives to a PC is a good one to have. Have a chat with your instructors and see what they use and why. Enjoy your diving and keep blowing them bubbles!