Super Long Shallow Water Diving

[Avonthediver]

I do a lot of spearfishing in the summer with times around sixty min but have never had a two hour dive. After that long in a three mm suit of just shorts and a tee you start to get cold even in eighty degree water. I might try it in a seven mm but that is a long time in almost hot water. And man your surface inter would max you almost out for the day.

 

[tomfcrist]

yeah, every pool session when teaching OW students.

 

[danvolker]

clear that up for me would u, BHB?

Blue Heron Bridge??... i guess that makes scene..

Here is an article on the BHB.. Darwin and a Galapagos for Nudibranchs
My wife Sandra does 3.5 to 4 hour long dives there routinely. She uses a hp100 for this normally, though lately she is using double 80's once in a while, to practice with while shooting macro....this for more technical deeper dives where these skills will be useful. BHB is an ideal place for macro photography AND advanced skills training, as the bottom is silty, and there are many scenarios there where perfect bouyancy and trim will make a huge difference....and where reverse kicks and other technical skills are very useful.
If you want more on this place where it is easy to enjoy 3 and 4 hour long dives, visit Blue Heron Bridge Marine Park

Pura Vida Dive Shop is about 400 yards away, just north of the park you are in, on Singer Island. A nice perk with them, is that they can fill your tanks right in the trunk of your car if you prefer....this is particulary cool for people with very heavy tanks or doubles.

As to the 3 and 4 hour times, one effect of this duration, is that you DO NOT WANT NITROX for this..,You want AIR...You can actually get hyperoxic myopia from high O2 mixes of Nitrox for this duration, and it can last for a few hours, or even up to a day before it goes away.

 

[Rhone Man]

Dehydration and hypothermia are issues to contend with on any long dive.

And dying of boredom patrolling the same shallow patch of reef for the third hour hoping to see something new.

 

[crankincraig]

Have done many shallow long dives when metal detecting in the shallow water off the beach in search of buried treasure ; and still no treasure so it looks like there will be more long dives in the future.

 

[Onewolf]

Doesn't the tidal flow become an issue at BHB after a while?

 

[danvolker]

Doesn't the tidal flow become an issue at BHB after a while?

There are zones at the BHB where the current is much reduced...and areas where the tidal flow is more of an annoyance.....Also, if you are flat horizontal, and low to the bottom ( inches) the flow even in the high flow areas is not that much of an issue....Now, taking macro pictures in the high flow areas is another story.....you have to get very heavy and litterally attached to the bottom to make this even possible---not to mention the nudibranchs are getting "blown around" alot ***Note, I am not advocating that divers should be crawling around on the bottom like Billy Goats....Just saying that there would be no way to hover in full current, and get a stable shot...
The low flow areas are fine, and in fact, many nudibrach species actually come out AFTER the tide begins to go out....

You can get in an hour and a half before high tide, and leave and hour after peak high tide is over.....as you go much beyond this, the current flow takes more strategies

 

[DevonDiver]

And dying of boredom patrolling the same shallow patch of reef for the third hour hoping to see something new.

You just didn't dive in the right places

 

[DivemasterDennis]

My experience is that at about 75 minutes, I am ready for a break, notwithstanding availability of air and ndl time. Dehydration, getting chilly in some conditions, and modest fatigue factors all impact that time line. As others have stated, I too need a reason to remain longer that overcomes the reasons to take a break, and a drink.
DivemasterDennis

 

[danvolker]

My experience is that at about 75 minutes, I am ready for a break, notwithstanding availability of air and ndl time. Dehydration, getting chilly in some conditions, and modest fatigue factors all impact that time line. As others have stated, I too need a reason to remain longer that overcomes the reasons to take a break, and a drink.
DivemasterDennis

That is true..especially with macro photography where you don't generate much heat with the lack of distance swimming.
Sandra was wearing a dry suit until last week...now she has a 3 mil one piece wetsuit, with a 3 mill freedive wetsuit under it....

Sandra has also found she feels much better if she has a sport drink like H2O Overdrive attached to her flag, so she can get hydrated and keep nutrition to her muscles...without this, you deplete most of the glycogen from your muscles, along with dehydrating.

If you think about it, even a 4 hour bike ride with a resting pulse, will use up all your energy and leave you trashed if you don't deal with nutrition and hydration throughout it. 4 hours at the bridge is the same. Same exertion as zone 1 ( below aerobic zone) bike ride, and same need for nutrition and hydration as the bike ride...yet most divers would ignore the dive nutrition....