What would you attempt to fix without surfacing?

[KevinTrew]

As AJ says, you can attempt to fix anything. But, that can be stuff not even mechanically related. I've used wetnotes and touch contact to try to fix relationship issues underwater with former girlfriends. It sucks when you take a surface problem into a dive with you.

Writing something like, "Look. I love you. I don't want to have a bad dive ... I'm sorry. Fight over?" coupled with the right look from behind a facemask and the right touch contact signal and you might be back in business.

I tried that once, problem was both my girlfriend and missus were on the same dive. Didn't go well, so ended up dating the DM instead.

 

[Dirty-Dog]

As AJ says, you can attempt to fix anything. But, that can be stuff not even mechanically related. I've used wetnotes and touch contact to try to fix relationship issues underwater with former girlfriends. It sucks when you take a surface problem into a dive with you.

Writing something like, "Look. I love you. I don't want to have a bad dive ... I'm sorry. Fight over?" coupled with the right look from behind a facemask and the right touch contact signal and you might be back in business.

Or you could end up with your air turned off....

As soon as we started our descent, I noticed my reg (HOG D1) was breathing a little wet. No big deal. I switched to my octo, turned off my right side valve, and took it apart to clean the spec of sand out of the diaphragm. Didn't really think it was any big deal till the guide looked back and saw the reg in pieces. He got... tense... I signaled OK, finished reassembling the reg, turned it back on and and tested it. Signaled OK again and to continue the dive. Seems he didn't know you could take a reg apart under water, and assumed I'd had some monster reg failure.

 

[Roger Hobden]

Seems he didn't know you could take a reg apart under water

I won't be attempting to do that any time soon ...

 

[MaxBottomtime]

I did that once. It took no more than a minute. I simply unscrewed the second stage cover, pulled out the diaphragm, wiped it clean and reinstalled it. No biggie.

 

[tbone1004]

@KevinTrew while on that same dive??!?

I won't be attempting to do that any time soon ...

we actually make our AOW and Rescue students take the reg apart underwater, leave the diaphragm and cover on the bottom of the pool and practice air sharing exercises with both students missing the guts of the regulator. What @Dirty-Dog did is actually quite simple, just have to be careful not to drop anything.

my answer for the original question is whatever I am able to fix, comfortable fixing prepared to fix, and willing to fix.
There are things you can't fix underwater, mainly true failures of the first or second stages. If the 1st stage has IP creep you can't fix it, and if the second stage won't seal, you can't fix it.
There are things that are possible to fix, but I'm not willing to be prepared to fix because I'm not willing to fix. i.e. HP spool o-rings *and I know someone who has replaced them in the middle of a cave dive. I hate doing that at the surface and it's just not a failure I'm willing to mess with underwater, hell or even at the surface.
There are things that I'm comfortable fixing, and if I'm prepared to fix them *i.e. have stuff with me*, then I will fix it. I don't bring that stuff on every dive though. What I bring with me to be able to fix things on an expensive ocean dive or a cave dive are going to be very different than the essentially entire lack of tools that I will bring with me in a lake or quarry. I'm not going to have any wrenches, o-rings, or anything like that with me in those environments because it's easy enough to surface and repair.
Things that don't require tools to fix should be fixed though. Debris in diaphragm seals, loose hose connections etc. is all super easy to take of underwater and if you know how to fix them, there is no reason to surface.

 

[northernone]

For fun I've fixed a bunch of things underwater which were unnecessary but enjoyable. The wise thing to do is surface and properly care for your equipment.

For example: while you have a handful of reg parts in hand you're pretty useless as a buddy.

Things I've done underwater:
-Ip adjust (slow first stage creep, finished the tank and avoided freeflow)
-Second stage clearing out debris, hundreds of times. That's normal.
Installed a blanking plug in replacement to a blown hose.
-Made an inner tube gasket to replace blown orings. HP twice, LP a handful.
- Mask strap rigged from bungee
- fin strap same source
- harness repair with zip ties
- reassembled a bcd dump valve (rescueing a stranger )
- removed a ripped mouthpiece (bare metal is easier to lip seal)
- reassembled camera rigging
- patched double hose hoses
- reattached various things
- managed diarrhea.

That's about all that's coming to mind. Not all on one dive, mostly solo and never as plan A.

Cameron

 

[JamesBon92007]

Things I've actually done underwater would be pretty much what I'd mentioned that I could fix underwater. On a new regulator the demand lever was leaking ever-so-slightly so I simply unscrewed the cover about 1/2 turn to reduce the pressure on the lever and it stopped leaking. Another time I had an older BC and the air from the power inflator hose was leaking past the valve and constantly filling my BC. I simply disconnected the power inflator hose. Now I regularly take apart my BC inflators and clean, polish, lubricate, and replace O-rings. Regularly may mean every few years or so.

 

[JamesBon92007]

For fun I've fixed a bunch of things underwater which were unnecessary but enjoyable. The wise thing to do is surface and properly care for your equipment.

For example: while you have a handful of reg parts in hand you're pretty useless as a buddy.

Things I've done underwater:
-Ip adjust (slow first stage creep, finished the tank and avoided freeflow)
-Second stage clearing out debris, hundreds of times. That's normal.
Installed a blanking plug in replacement to a blown hose.
-Made an inner tube gasket to replace blown orings. HP twice, LP a handful.
- Mask strap rigged from bungee
- fin strap same source
- harness repair with zip ties
- reassembled a bcd dump valve (rescueing a stranger )
- removed a ripped mouthpiece (bare metal is easier to lip seal)
- reassembled camera rigging
- patched double hose hoses
- reattached various things
- managed diarrhea.

That's about all that's coming to mind. Not all on one dive, mostly solo and never as plan A.

Cameron

Ha! I always bring some various zip ties with me in my backpack but have never taken them underwater with me. Maybe it's time to start....

 

[scubadiver888]

It may be worth considering thinking about how you'd attempt to fix a problem before trying it underwater the first time under pressure.

now I'm having David Bowie stuck in my head ....

Dammit, now I have David Bowie stuck in my head.

 

[scubadiver888]

Recently, I noticed someone had their tank slipping. I let them know and indicated I was going to fix it. Turns out the cam band was threaded wrong and not just loose. So I held the tank with my knees while I re-thread her cam bands then tightened the straps.