Some Blue Hole Impressions

[Edward3c]

We camped for 3 days on Half Moon Key; I must dig out the photo of me standing on sand looking like snow with palm trees. With the BH dive out the way, some real diving was done off the north drop-off with sharks circulling during the 10 min deco stop. We were diving the new high pressure cylinders (207bar).

 

[rongoodman]

I'll be there in May on the Aggressor III and will go if the rest of the boat wants to, but I'm not too excited about doing a bounce dive on air. I'd like the chance to do it on trimix, either with my rebreather or a set of doubles, but that doesn't seem likely. Is mix even available there?

 

[ibj40]

We're heading back to Belize in May, going to be on Ambergris. Other than touring the Mayan ruin at Tikal, my greatest anticipation is going back to the Blue Hole. When you are there, you are in the presence of geological history, and to me, that is so significant, that I can't wait to get back to experience it again.

 

[drrich2]

ibj40:

By way of analogy, you remind me of someone who posts about diving Roatan and appreciating the rich macro life there, which many divers hardly notice, instead favoring 'big stuff.' How much appreciation you have of the diving may relate to what you like and know to look for.

The geological history you speak of I imagine only a minority of divers 'get.' It's a vast sink hole and way deep you can see some huge stalactites, plus it makes a beautiful aerial photo from high overhead. That's probably about as far as most people get.

What geological history aspects make it more meaningful to you?

Richard.

 

[ibj40]

ibj40:

What geological history aspects make it more meaningful to you?

Richard.

I guess the fact that stalactites and stalagmites can only be created in a dry environment, and there I am observing them at a depth of 140 feet below the surface of the sea. Other than that, nothing special.

 

[wetb4igetinthewater]

So, you did one dive due to the nitrogen loading. Is there no possibility of accelerated deco? Or is tec diving procedures just a no go?

 

[chillyinCanada]

"The Great Blue Hole’s geological past spans 150,000 years, back to a time when it actually existed above ground, as evinced by the presence of stalactites in its underwater caves. Although many mysteries remain as to the origins of the Great Blue Hole, scientists believe that a series of dry caves predating the Ice Age gave rise to the submerged sinkhole of today. Sometime before the last great thaw, an earthquake shook the area to an angle of 12 degrees, which explains why the stalactites hang so strangely tilted.

Following this seismic upset, the melting of the last Ice Age flooded the cave systems and eventually the limestone ceilings of the once-dry caves collapsed under the weight of the water, creating one giant sinkhole 1,000 feet in diameter and over 400 feet deep. It’s a true geological oddity, appearing in stark contrast to the surrounding waters, which are so shallow that the coral peeks out of the sea at low tide."

 

[Downing]

So, you did one dive due to the nitrogen loading. Is there no possibility of accelerated deco? Or is tec diving procedures just a no go?

You would have to find a dive op that does tec diving, and I don't know of one in Belize (which is not to say that there isn't one). There was a long-time poster on this board, Peter, who taught tec diving on AC, but he closed his shop years ago and unfortunately passed away a few months ago.

The standard BH dive is to descend as a group to the lip, about 50 feet. Once everyone is ready to go, you then go over the lip and plunge into the hole and keep going until you hit 130. Level out, check out the wall and sharks and maybe swim around a stalactite or two. After about 5 minutes, you descend back to the lip and off gas there for about 15 minutes, then up to the safety stop, where hopefully the dive team has hung a few tanks, then out. The better ops will have plenty of staff on the dive to keep an eye on their divers, looking for any sign of trouble or narcosis.

Definitely a bounce dive. Not worth the risk or trouble to some, especially if they've done it before. I've done it three times and would gladly do it again. I enjoy the vastness of the hole, the wall that looks to stretch on forever and just the uniqueness of the dive.

 

[wetb4igetinthewater]

You would have to find a dive op that does tec diving, and I don't know of one in Belize (which is not to say that there isn't one). There was a long-time poster on this board, Peter, who taught tec diving on AC, but he closed his shop years ago and unfortunately passed away a few months ago.

The standard BH dive is to descend as a group to the lip, about 50 feet. Once everyone is ready to go, you then go over the lip and plunge into the hole and keep going until you hit 130. Level out, check out the wall and sharks and maybe swim around a stalactite or two. After about 5 minutes, you descend back to the lip and off gas there for about 15 minutes, then up to the safety stop, where hopefully the dive team has hung a few tanks, then out. The better ops will have plenty of staff on the dive to keep an eye on their divers, looking for any sign of trouble or narcosis.

Definitely a bounce dive. Not worth the risk or trouble to some, especially if they've done it before. I've done it three times and would gladly do it again. I enjoy the vastness of the hole, the wall that looks to stretch on forever and just the uniqueness of the dive.

That's why I'm looking at going sidemount. No "special" support is needed by a dive shop. I can have 2 tanks, and if they can put nitrox in a pony bottle, then I can do accelerated deco. Should be doable. Next question would be if it is allowable, as it all depends on the divemaster being able to stay down long enough with me.

 

[Edward3c]

That's why I'm looking at going sidemount. No "special" support is needed by a dive shop. I can have 2 tanks, and if they can put nitrox in a pony bottle, then I can do accelerated deco. Should be doable. Next question would be if it is allowable, as it all depends on the divemaster being able to stay down long enough with me.

Unless their qualified to do deco your still going to be stuck with a bounce dive.

You need to find a similarly qualified buddy as yourself and then find out if the operator will permit deco.

Last time I was there none of the guides/instructors could do a 50m dive (my certification), not even allowed to do any mandatory deco.