parasailing after diving

[kaerius]

Can't look at the reverse. Going to altitude after diving is about what happens to the nitrogen load dissolved in your blood. Going the reverse does nothing to "lower" your baseline nitrogen load, which is zero. You can't get "negative" nitrogen load by descending from altitude.

To elaborate on PfcAJ's reply to this. Your nitrogen load is never zero unless you're jettisoned into deep space without a suit or you breath only gas that does not contain nitrogen, including out of the water. Instead you are, as he noted, saturated at sea level.

Btw: Astronauts breath pure oxygen before takeoff to avoid getting decompression sickness when going out into space.

 

[hbhobby]

you would have less of a nitrogen load after flying. the problem is that once you land you start to ongass immediately and by the time you would get to a dive site you would have a "bottom time" that would make any small amount of "negative" nitrogen load gone.

 

[StreetDoctor]

if you're not an out of shape fat body even flying after recreational diving is not going to hurt you. Aircraft cabins are pressurized to 8,000'. "But DAN says.." I know, I know.

 

[StreetDoctor]

Funny how often this comes up. But nobody seems to ever worry about staying in the top floor of some high-rise hotel. That could easily exceed 800 feet...

LOL LOL An average commercial building floor is 10-12'. How many 80 floor hotels do you know especially in diving locals where there's most likely a threat of hurricanes at some point throughout the year.

Edit:

Here's a list of the tallest hotels in the world. There are 11 above 800'.

List of tallest hotels in the world - Wikipedia, the free encyclopedia

 

[natew]

LOL LOL An average commercial building floor is 10-12'. How many 80 floor hotels do you know especially in diving locals where there's most likely a threat of hurricanes at some point throughout the year.

Edit:

Here's a list of the tallest hotels in the world. There are 11 above 800'.

List of tallest hotels in the world - Wikipedia, the free encyclopedia

Even if you did, I think this has already been addressed, but unless you literally walk out of the ocean with your dive gear on and step onto the elevator or strap on the parasailing harness (fins and all) you're going to have enough time out of the water to have offgassed enough to be safe at 800ft even probably 1500 - 2000ft. I know I'm not the fastest at gearing and ungearing but it takes me about 30 minutes to take everything off and pack it away add that to the time that it will take you to either swim back to shore on a beach dive or return to port and dock and unload a boat you are lookin at 1hr to 1.5 hour time and then you have travel time to where you are going which might be another half hour so basically 2 hours. That's more than enough time to sufficently offgas to be safe at those levels.

 

[northen diver]

Ok, what about the reverse. Say I fly to a dive in Bonaire, would your bottom time increase because of the lower nitrogen level from the fight.

Skydivers and pilots can also develope DCS. If you go fly above 18,000 feet in a unpressurized cabin, you should pre-breath 100 percent oxygen for 45 minutes to rid your body of the nitrogen.

 

[northen diver]

1000 feet is not going to be a significant pressure change. If you've got a reasonable length of time between the dive and going up parasailing (a few hours would be more than enough) I'd imagine you'll be fine.

Even Life Flight / Care Flight takes injuried divers to 1500' to the trauma centers.

 

[bleeb]

Originally, I wasn't going to bring this up since it's getting considerably beyond what your average student undergoing OW certification might experience. However, it's well within the range of possibility for an experienced diver doing multiple dives which is where this discussion seems to be going.

One source of information that people may want to consider is the NOAA Ascent To Altitude Table, which starts at 1000', and personally, I'd consider 800' to be close enough to start paying some attention. For a single 10m/30' dive (or even multiple successive dives), you can ascend immediately with a total nitrogen time of <100 min. That's probably difficult (although not impossible) for most people to achieve recreationally, but if you do exceed it, the required SI starts at 1:32.

However, if diving to 60'/20m, you hit the same time limit at 55 min total nitrogen time. That's starting to push it for one dive, but not all that unlikely for two dives with a one hour Surface Interval. As others have already pointed out in this thread, a 1:32 interval before you can ascend to altitude is not hard to meet by the time you get out of the water and cleaned up and what not, but if you hurried things, you might breach that limit if you weren't paying attention.

And if you're taking a helicopter ride to 1500', the total nitrogen time limit drops another letter group, and you might be looking at a 3 or 4 hour interval before ascending. At that point, the flight crew might be trading off risks of flying lower, or taking you higher sooner when you already have a medical condition severe enough to need the helicopter ride.