Island hopping .... should I worry ???

[shark_tamer]

During my coming vacation, I might have the opportunity to island hop to a nearby island for a special 1 day / 2 dives trip.

We all know that our last dive should be 24 hours before we fly.

My concern is that I would be in / out of the island on the same day, and last dive would only be 3-4 hours before I fly.

:huh: Should I technically consider this as ¨flying¨ since I will be onboard an Aerotaxi which has minimum cabin pressure, 35-45 minutes flying time and probably does not go above 2000 feet ?

 

[justleesa]

Moved from Accidents and Incidents to Basic Scuba Discussion

 

[rocketry]

A normal commercial flight cruises at around 30,000 feet. It is pressurized, however, to a height of about 8,000 feet, whereas to allow the passengers to more about and function comfortably. The island hopper will certainly not be cruising at 2,000 feet, more like 6-10,000 feet, depending on the aircraft. Being so, its a hit or miss whether it will be pressurized. You "gain" 8,000 feet at the gate when the aircraft door is closed and the pilot pressurizes the cabin on a typical commercial flight, therefore most low flights would not be pressurized. That being said, an unpressurized flight to 8,000 feet and a commercial flight (pressurized to 8,000 feet) would be virtually the same. Of course factoring in duration, mabye a little less intensive.

I would call the island-hopper company and ask them (1) what plane they are using, (2) whether their flights are pressurized and (3) their cruising altitude. IDENTIFY YOURSELF AS A DIVER!!! as to not give off the wrong impression. Post the type of plane and I could give you more details (I persued aviation, a while ago).

Depending on the flight, if it really only was to 2,000 feet, i'd plan the dive to leave as much room as possible before you fly, and then dive an extremely conservative profile. Set your computer to the highest altitude/highest personal conservation setting...whatever you have to do (it may go haywire if it knows you are flying, i dont know what computer you dive with). And of course, do what you personally feel is right. Does DAN have any literature on this? I dont know.

 

[fdog]

This ascent-to-altitude thing is near and dear to our hearts, since we live in Reno, NV and often dive at sea level in Monterey, driving home over the mountains on the same day as our last dive.

One approach: use the NOAA ascent to Altitude tables, in conjunction with the NOAA Diving Tables as well as the NOAA Residual Tables.

Or, here's some light reading: the DAN Flying After Diving Workshop. The portion of this document that may interest you is as follows:

Finally, a minimum threshold altitude below which guidelines were unnecessary was discussed. Although no data were available that specifically addressed the question, a previous publication had suggested that restrictions were unnecessary below a threshold altitude of 2,300 feet (701 meters) (15). The U.S. Navy Diving Manual had followed this recommendation without apparent problem until introduction of the 1999 procedures that reduced the threshold to 1,000 feet (305 meters) for internal consistency (5). The workshop participants agreed that 2,000 feet (610 meters) was a reasonable, if uncertain, threshold, as no problems with 2,300 feet were cited.

I might suggest getting more information as to verify flight duration and altitude. If I was in your shoes, I'd do the following with good confidence:

Assume:
that the flight will be as high as 5000' MSL for weather or traffic

Dive day before:
limit of two dives, 60' maximum, nitrox
or
Surface interval of 18 hours before flying with no limit on dives

Dive (flown) day:
Fly to location
First dive 80'/20 minutes max
SIT 90 minute minimum
Second dive 60'/30 minutes max
Nitrox if available
120 minute interval minimum before flying return

Other:
Make sure you have DAN or DiveAssure insurance.

All the best, James

 

[rocketry]

nitrox

I forgot to mention this. With a conservative profile, longer intervals and Nitrox, you should dive with confidence.

Make sure you have DAN or DiveAssure insurance.

I almost fell off my chair! I'm sure shark_tamer would much rather be sitting on the beach drinking a cocktail than getting bent and being air-vac'ed to the nearest chamber! I wouldn't use having DAN insurance as a license to go ahead and do a risky dive profile.

DAN/insurance IS a must, though!

 

[BarryNL]

As others have mentioned, you really need to know the altitude/pressurisation of the aircraft to get a good answer to this question - call the flight company.

Alternatively, is it not possible to overnight on the other island, have a look round and fly back the next day?

 

[BarryNL]

Moved from Accidents and Incidents to Basic Scuba Discussion

Let's hope you don't have to move it back later...

 

[rocketry]

Let's hope you don't have to move it back later...

Hahaha, this gave me a good laugh.

 

[fdog]

<snip>I almost fell off my chair! I'm sure shark_tamer would much rather be sitting on the beach drinking a cocktail than getting bent and being air-vac'ed to the nearest chamber! I wouldn't use having DAN insurance as a license to go ahead and do a risky dive profile. <snip>

Nor was I advocating it as a means to perform an unwise exposure.

Just making sure...accidents do happen.

However, as I indicated, this is a profile I would perform myself with confidence.

Assuming it really is an unpressurized aircraft flying at 2,000'.....

All the best, James

 

[rocketry]

Nor was I advocating it as a means to perform an unwise exposure.

Just making sure...accidents do happen.

Of course! I wasnt accusing you of performing an unwise exposure! Just merely stating my knee-jerk reaction. No Worries!