Kona Konundrum

[808Dude]

Oahu resident here thinking of popping over to the BI for my first manta ray dive and then head over to Hilo/Volcano later the next morning. In my laying out of plans, I forgot about the elevation issue and it made me realize what a pain in the butt diving in Kona must be.

It appears that the problem with Kona diving is you are stuck in a geographic hole and apparently can't go anywhere the next day. You can't go down to Honaunau or over to Hilo or even up to Waimea because every path is taking you at least up to 1600' above sea level.

Wut do? Just hate physics?

I see most shops do this as 2 dives and I have no idea the depths so I can estimate when I would be good to move up country. I've read everywhere from 12-24 hours. That's kind of a big window. Anyone else recall how long the wait was after doing this dive?

Mahaloz!

 

[Quero]

Aloha. My son lives in Volcano and used to live in Hilo, so I encounter this problem every time I'm visiting and want to dive. I've found the guidelines published by NOAA helpful in making my plans, but essentially, I've generally waited to the next morning to drive over the mountain if I've had an afternoon boat dive or two.

 

[MauiScubaSteve]

I went with Jack's on a dusk dive / night dive - from the same mooring; not a night dive / black water drift. I suppose you could stay on the high side of the group and not go below 40' deep on the first dive; as well as heading up with the "hoovers." Then the "camp fire" was 35' deep-ish or less, after which I chose not to burn my last 1/3 tank on the post manta, night reef adventure, and got back on the boat. This time of the year that might be 8 PM ascent, but it will be pretty late when finally leaving the dive shop.

Next morning starting the drive at 8 AM, taking in some sites, and by the time you head to lower than "cabin pressure" Volcano any dive computer will likely be clear.

 

[olelomoana]

From the Kohala Coast to South Point and Ka'u, the elevation change does not exceed 1600'. I dive regularly and live at about 1800' and have never had any problems. I know it's a bit over the recommendations, but I don't think you would have any trouble touring the west side of the island after diving, just don't go to Waimea or the Volcano until the next day. That's assuming you do a normal recreational dive(s) and aren't pushing the limits.

 

[friscuba]

Keep it to two dives and get a 8:30 am start and you'd be out of the water for 12 hours minimum. Go around the island and you'll top out at 4500 feet or so. Saddle road would push 7000 feet so I'd pass .

 

[808Dude]

From the Kohala Coast to South Point and Ka'u, the elevation change does not exceed 1600'

It doesn't exceed but it gets pretty dang close to it on HWY 11 near Kealakekua Bay there buddy:

kona - Google Maps

If you are going down to South Point you are hitting 2000' before descending again.

kona - Google Maps

I am just looking at the google's topo map which is kind of why I ask in the first place.

It's good to hear some first hand experience and find out how much wiggle room there is vs the actual math.

It's good to know I can head south a little bit without too much worry but I will definitely be skipping Waimea and the Saddle Road the next day.

thanks All

 

[MauiScubaSteve]

AFAIK, 2000' foot elevations are not a problem, even immediately after the dive(s). Years ago one local airline purportedly pressurized their cabins to 2000' foot pressure (not the industry standard 8,000'), both to limit stupid diver injuries and to avail themselves to emergency transport.

 

[fah]

I just got back from Kona/Kohala and dove one day and drove the next to south point and later dove and drove the north route to Hilo from the Hapuna area. No problems. My dives had max depths of about 50 ft. I was not aware that 2000' was considered " flying", but came out unscathed nonetheless.

 

[LeadTurn_SD]

My recommendation is always to be as conservative as reasonably possible with your SI when considering ascending.

That disclaimer out of the way: I live in Hilo, and have regularly "commuted" to Kona to dive, then back to Hilo on the same day, since the 1970's.

I long ago looked at the NOAA tables and my typical dive profiles, and established 5 hours as my minimum SI before driving home to Hilo. For most of my Kona shore diving, this is WAY conservative.

But this is just for the dives I typically do, and different profiles could easily yeild a different result. And remember, although not intuitive, shallow and long no-stop dives can result in greater nitrogen loads and longer "safe" SI's before ascent to altitude than deep (but very short) no-stop dives... so depth alone is not a good indicator. You need to do your own calculations for peace of mind... And you need to use the NOAA tables to find your Group designator, not the PADI RDP.

Other "personal" Big Island dive-then-drive rules:

1.) I simply do not drive over Saddle Road after diving (within 12 hours). I treat it the same as flying after diving.

2.) I pick the lowest-elevation route home.... thus I drive home via Waimea rather than via South Point & Volcano (to avoid the climb through Volcano National Park), even if the Waimea route is much longer.

Have fun.

 

[Mr Carcharodon]

O

It appears that the problem with Kona diving is you are stuck in a geographic hole and apparently can't go anywhere the next day. You can't go down to Honaunau or over to Hilo or even up to Waimea because every path is taking you at least up to 1600' above sea level.

Wut do? Just hate physics?



Mahaloz!

Not at all. You should love physics totally. Going from sea level to 1600 feet above sea level is a pressure swing of 2 feet of sea water (a pressure drop of 5.6%). Do you think a 2 foot difference in a dive would be decisive in determining if you get bent on a dive? And the manta dives are in what like 25 fsw? You could dive forever in 25 fsw and your risk of getting bent short of shooting to to the surface and getting AGE would be close to zero. It would be more risky to do your dive at 30 fsw than to drive to Hilo a few hours later. Do your dive in Kona, clean up, go to lunch, and then drive over to Volcano National Park. Your risk is very low.