Is it ok to surface halfway through a dive then go back down?

[lowtech]

Any idea how fast he may have been ascending? If it was a "big dive" including a partial si was he maybe a bit low on air and rushed the ascent?

I'm not a deco expert but,
I remember reading/watching somewhere that the biggest problem with this after big dives is that it simulates a PFO, allowing bubbles to pass over to the arterial side and lodge in the smaller capillaries.

 

[tflaris]

Is it ok to surface halfway through a a dive then continue the dive as if u never surfaced? Ive got about 25 dives. I could not find a sunken speed boat not to long ago and wasn't sure if its ok to surface and figure out where I was then continue dive. I was around 60 feet.

Are you diving tables?

Minimum time surface interval by SSI/NAUI dive tables is 10 minutes. Anything less would be considered part of the same dive.

I would suggest a safety stop unless it was an emergency.

Hope this helps.


Sent from my iPhone using Tapatalk

 

[HowardE]

Is it ok to surface halfway through a a dive then continue the dive as if u never surfaced? Ive got about 25 dives. I could not find a sunken speed boat not to long ago and wasn't sure if its ok to surface and figure out where I was then continue dive. I was around 60 feet.

That depends on what you define halfway through the dive. But for the most part, it's not bad if you adhere to your ascent rate, and mind your NDL's

 

[TSandM]

I think the issue with someone going back down for bottles is that you compress the bubbles enough to let them through the pulmonary filter, and then you don't stay down long enough for them to collapse, so they expand greatly on ascent.

If you surface halfway through a dive, spent virtually no time on the surface (peek and go) and return to the depth where you were, it's kind of like the commercial diver who surfaces and walks into a chamber. If you then spend significant time (and do I know how much that is? No way.) at depth, you may well be okay.

I suspect this is something a lot of us have done from time to time -- I try not to make a habit of it, but I have done it with no ill effects.

 

[LeadTurn_SD]

Any idea how fast he may have been ascending? If it was a "big dive" including a partial si was he maybe a bit low on air and rushed the ascent?

Normal ascent if I remember.

Again, this is a recollection of an article I read several years ago, and my memory is well... now what was I saying

The diver (a support diver) had surfaced after a deep, long dive but I'm not sure if it was a deco dive or not, or just close to it with a lot of N2 loading. As I remember reading, he was not showing any symptoms prior to re-entering the water, but at some point during the SI he donned scuba gear to retrieve some empty stage bottles in fairly shallow water, was down very briefly at shallow depth, and surfaced normally, and ended up badly bent. He assumed since the dive was shallow, and brief, there would be no problem, as I probably would have a few years ago

Best wishes.

 

[Crush]

Direct experience: No.

Anecdotal experience: Yes. Diver part way through a surface interval after a fairly "big" dive diving down for a few moments (to 20- 30'? I don't remember) to retrieve some stage bottles, resulted in a badly bent diver when he returned to the surface.

Best wishes.

Re-posted from above:

Some time ago I PM'd Dr Deco about [see-saw profiles leading to DCS] and (to the best of my recollection) his response was that there was no information to support such a notion.

 

[Bogie]

Common sense in diving vs opinions in scuba diving are sometimes at odds.

If you need to surface from a reasonable depth vs swimming around on the bottom lost, I say surface get your bearings and descend. Proper ascent rate, safety stop and proper clearing of ears are required.

Ascending properly once during a dive at 60 ft. has an extremely low chance of any DCS.

If you are doing multiple dives on the same day you would want to be more conservative.

 

[Quero]

When we brief safety procedures on our boats here we tell divers the usual buddy-separation rule of looking around for a minute and then surfacing if they don't locate one another. When this happens, it's normally the case that the buddies are relatively near one another on the surface, but because of low visibility, perhaps, they become separated even though they were not far away from each other underwater. While buddy separation shouldn't happen, the fact is that it does. We tell our divers that if they've got enough air to continue the dive after reuniting on the surface, they may do so. We have not seen reports of bends related to buddy-separation surfacing. Regardless of whether the buddy team's dive plan was table-based or computer-based, they don't count the time on the surface as a surface interval but instead as part of the same dive. (In fact, computers only start a "new" dive once the diver has attained the surface for some pre-determined period--my computer is pre-set at 5 minutes.)

 

[vladimir]

I guess the question should be - Does anyone have any direct experience with yo-yoing resulting in DCS?

If the thread is well read it might get 2,000 views. Assuming they are all distinct (I don't know how views are counted), and assuming nobody reports DCS because of yo-yoing as described by the OP, will that be enough evidence to conclude that it's a safe practice?

 

[Aigtbootbp]

You mean something like jumpjng in, losing a fin, chasing it down and catching around 35ft then coming back up to put it on and signal all is ok then following up with a standard Cozumel reef dive?

Nope, never done it.
And if I did I am sure I would not had any trouble from it.