View Full Version : Deco on the road home ?
Hi,
just thought but is it safe to drive home after a dive on the A frames at Finnart, then to jump into the car only to drive up over the hill on the A817 Glen Fruin road to Loch Lomond to the A82 ?.
There must be some risk relating to decompression, and in Scotland plenty of similar routes home ...
Any comments ?:)
bubblemaker
15-05-06, 23:38
it's potentially unsafe.. same as coming home from loch Fyne... you should by rights, have a rest before you go over the hills. I don't know about other people, or clubs, but wee like to goto the pub for a bit of de-gassing!!!
it's potentially unsafe.. same as coming home from loch Fyne... you should by rights, have a rest before you go over the hills. I don't know about other people, or clubs, but wee like to goto the pub for a bit of de-gassing!!!
Of gassing in the Furnace Inn and the george hotel is a vital part of decompression after the 1 min at 3m ;)
although you should be ok after one dive at Finnart.
Lizardland
18-05-06, 13:10
I doubt it makes much difference. It might appear a bit of a climb but in air pressure terms it's nothing. The time it takes to pack up your kit is long enough for you to offgas more than enough to drive home. Finnart is so shallow and the hill isn't high enough, it isn't worth the worry. Though a medicinal stop in the Green Kettle with a pint of Schiehallion is worth it :)
I've done a fair bit of cave diving in the Alps, with quite frequent drives to 1200m over the France/Swiss border after 70m dives with no problems. I don't even think about it.
Cheers,
Stuart
bubblemaker
19-05-06, 17:48
hmm it would seem the dangers are limited.. but they are still there...
if you have a bend, helicopter crews will go round the mountains rather than over them... so there must be something in it!!
Lizardland
22-05-06, 00:22
Sound advice, the dangers are limited but you never know when your number is up.
Been thinking about it so I did some quick calcs. The difference in air pressure between sea level and 300m is only around 50-60millibars or so, so I added a bit to my deco program to see what this would do.
For a 60min dive at 30m you would have to spend 37min at sea level after the dive before it was safe to drive to 300m altitude. For a 30min dive at 30m then it is only 13min.
OK, I was bored :)
Cheers,
Stuart
The difference in air pressure between sea level and 300m is only around 50-60millibars or so, so I added a bit to my deco program to see what this would do.
For a 60min dive at 30m you would have to spend 37min at sea level after the dive before it was safe to drive to 300m altitude. For a 30min dive at 30m then it is only 13min.
OK, I was bored :)
Stuart
Awesome information, Stewart. How did you do this calculation? You mention a deco programme?
I'm sitting here at home with the flu, so what better time to calculate abstract deco situations. I'm wondering, if I do two 40 minute dives to 40m at Furnace, how long should I stay in the George in Inverary before heading back over the rest and be thankful? And should I have the lager or the IPA?
bubblemaker
22-05-06, 19:13
I'm wondering, if I do two 40 minute dives to 40m at Furnace, how long should I stay in the George in Inverary before heading back over the rest and be thankful? And should I have the lager or the IPA?
i think, without doing calculations, you should err on the side of caution, and just make a night of it!!!
Lizardland
23-05-06, 10:38
Go for the IPA, lager is bad. Exact stop requirements depends on who is driving.
I did the calcs using a simple deco program I wrote for testing something a bit more complicated, XS (you can get it at www.lizardland.co.uk).
Looks like a useful site. can yuo put it in our directory? http://www.congeralley.com/links/index.php
I'll give the XS prog a whirl when I get a mo. I like the idea of calculating beer-deco for a safe dive home. Beco?
i concur with yuo that lager is bad, IPA is the way forward!
Just read through your site in more detail, Stuart.
Interesting AND entertaining :)