Down to 60' and back up?

[av8er23]

I have a strange question. Lets say you and your buddy jump off the back of the dive boat to discover one of you have lost a fin or mask. It sinks to the bottom. Is it safe for the other person to go down retrieve it and come right back up. After all you are not giving your body the bottom time it takes to soak up lots of nitorgen.

 

[cummings66]

I have a strange question. Lets say you and your buddy jump off the back of the dive boat to discover one of you have lost a fin or mask. It sinks to the bottom.

Sure it's safe to do that, but the real question you're asking is is it safe to then dive immediately afterwards.

Personally I would treat it like a dive and do a small wait and calculate my numbers and dive the next one as if it were the second dive. I know some that don't count it at all, but I'm new so I would.

 

[Wayward Son]

We do it all the time when chaining off. Rather than anchor, one guy takes the line with a chain & large snap clip. We get positioned over a structure & down he goes, a bubble ride to hell. Finds a spot, chains off.

Sometimes he stays down. We gear up & follow. Usually on deeper sites he stays, unless the viz is so bad he comes up to tell us we're not chained on & will try another site. Sometimes, on shallower sites, say 70 FSW to the sand, he'll chain off & come back up to report on conditions, get his speargun & go back down.

When coming back up, he keeps his initial bottom time short. 2 to 3 minutes.

We also use computers which track all this. If you're diving tables you should treat it as a dive & plan with it.

 

[ScubaSixString]

I have a strange question. Lets say you and your buddy jump off the back of the dive boat to discover one of you have lost a fin or mask. It sinks to the bottom. Is it safe for the other person to go down retrieve it and come right back up. After all you are not giving your body the bottom time it takes to soak up lots of nitorgen.

Wow....must be nice to have water that clear. What will probably happen is your mask or fin is going to end up a bit farther away than where you drop it. So there is probably going to be a search....except when you can see it from the surface.

So i guess the question is what are you talking about? From a repetitive dive standpoint, the tables say if you stay on the surface less than 10 minutes to count that as a continuation of the first dive (if you use a computer the deco point is moot)

You haven't stayed under long enough (assuming its a go down and come right back up standpoint) to ongas enough nitrogen to be a problem from a safety stop POV (no need for one)

Rate of ascent is the biggie. Stay under or at 30 ft/min and you'll be fine (even that is PROBABLY not necessary, but you don't want your acsent to get away from you)

 

[av8er23]

Thanks guys... this makes sense and I would treat it as a dive and cunsult the tables.

 

[Charlie99]

It's a whole different matter though if this bounce down to 60' is at the start of your 2nd dive of the day.

Just the same as if I had dipped back down to 60' for some reason near the end of a dive, I'll redo my 20-30fpm ascent, with 1 minute stops at 40' and 25', and a 3 minute stop at 15'.

 

[1RUSTYRIG]

You could always just free dive it

I have free dove 60+ to get a sling spear someone dropped while re-entering the boat

 

[Charlie99]

You could always just free dive it

I have free dove 60+ to get a sling spear someone dropped while re-entering the boat

You still get the same pressure excursion. Doing it as a freedive before any dives is not a problem, since you don't have any extra N2 loading.

Doing it by freediving after diving earlier that day is a bad idea, probably much worse than doing it on scuba and taking your time with the ascent.

 

[ScubaSixString]

It's a whole different matter though if this bounce down to 60' is at the start of your 2nd dive of the day.

Just the same as if I had dipped back down to 60' for some reason near the end of a dive, I'll redo my 20-30fpm ascent, with 1 minute stops at 40' and 25', and a 3 minute stop at 15'.

You pulling short Pyle stops?

 

[LavaSurfer]

Doing it by freediving after diving earlier that day is a bad idea, probably much worse than doing it on scuba and taking your time with the ascent.

Yea baby! I remember the Divemaster on a boat yelling at someone for just this. After a dive this dude decided to do a freedive. The rest of the trip he called him "Fizzy Pop". Not a good idea after diving to freedive.