Our family will be staying at the Sand Dollar the week of 3/28. Curious what the water visibilty is at Bari Reef now. This is our first trip to Bonaire - do most divers use a 3 mil shorty or without?

Hi, Jack!
Welcome to BT!
I wear a dive skin plus a 2 mil shorty. I rarely see divers without some sort of wet suit, but some heavier divers do without.
The water temp has been running 81 degrees most of the time for a couple of months, but on a few cloudy days it has dipped as low as 79.
As far as vis at Bari, don't know, but the vis varies everywhere. After weeks of hard rain, in January it was not so hot because of run off, although there's so much to see underwater here it's not a big problem. You can always find things of interest within the available vis.
Surge also kicks up sand some days in some spots.
Most of my dives this winter I've found vis either good or excellent.
Presumably you will not do all your dives at Bari? We've extraordinary diversity here; get out and sample it!
Enjoy your dives!
Tish

The further you get away from the dock, the better the visibility gets. By the drop off it should be around 60-80 as far as I recall. Temperatures drop below 60 ft, but a 3 mm should be sufficient. Personally I prefer the full since I remember quite a few people returning all bumpy from encounters with sea lice. Enjoy the Sand $ Coach Izzy

Glad you know about current Bari vis, Coach Izzy, and yes, I should have mentioned that most people wear a full, though I do not.
But I'm really surprised at your saying temperatures drop below 60 ft. Other places, yes, but not on Bonaire. I've logged here nearly 300 dives, and I've encountered no thermocline. More importantly, the dive masters will tell you Bonaire has no such thing.
Tish

Tish,

There can be thermoclines. I have encountered them several times in diving since 1983. They are noticable on my face but I have not seen any change in the small thermometer I carry on my DC wrist strap. Not like a New England thermocline in midsummer!

I concur on the full suit of some sort if only because of the ubiquitous fire coral as well as warmth. Even jeans and a long sleeve shirt help.

Speaking of warmth, don't forget a hood of thickness similar to your suit as a simple way to keep warmer. The old '40 % of bare body heat loss is through the skull' thing we all learned in Basic!! :–)

We both wear either a .5mil or a 1mil full suit and that is not really for warmth but for skin protection from fire coral, sea lice and from the dead coral when doing shore dives. Have seen some people dive in just swimsuit and tshirt.
Andy & Dave

Glen,
I believe what you are describing is not linked to depth. We all have suddenly felt a chill, probably the psychological effect of the sun going behind a cloud or the physical impact of having been in the water a long time or for multiple dives.
But there is, as your small thermometer verifies, no actual change in temperature as you descend on Bonaire.
What Jack needs to know is that there is not only no thermocline here but there is also very little temperature variation in the water off Bonaire. During steady, year-round diving on Bonaire for three and a half years I have encountered no water temperature lower than 78 and no water temperature higher than 84. Others might have seen slightly higher or lower temperatures, but this is not a place where you want to dive with a heavy wet suit. What you do want to wear, Jack, really depends on your own tendency to experience chill in water that is not bathtub hot.
As for fire coral, if you stay off the reef, as Marine Park rules require, you will not get stung.
Happy diving, Jack!

Tish, My dive computers will disagree with this part of one of your above statements

"What Jack needs to know is that there is not only no thermocline here"

Remember, if you are using a thermometer typically found in pressure gauges, there usually is not an exterior sensor, hence they do not show true (if possible) water temperature immediately especially when thermoclines are experienced. What you are actually seeing is the temperature of the air, or oil inside of the gauge, either take a considerable amount of time to acclimate to the actual external temperature.

I have on several occasions during dives off of Bonaire even "seen" the thermoclines before I actually entered them. Many cold water divers can relate to this phenomenon, which is experienced when there is a drastic change of temperatures. In fairness, I must say that I only experience these on rather deep dives.

(Message edited by vtscuba on March 13, 2005)

(Message edited by vtscuba on March 13, 2005)

Thanks very much to all - its rare to be on a site where the response is so fast and helpful.

Tish, Tom is correct. There are thermoclines on Bonaire, sometimes you can see them, sometimes you simply feel them and get the heck out of them ASAP. Martin & I felt an especially cold one last January, and we both (prudently)ascended pretty darn quick. As soon as we hit warmer water we both stopped ascending. Our actions did not indicate a psychological chill.

I have spoken to several Bonaire dive masters about this during the last 24 hours, and they all roared with laughter at the idea Bonaire has a thermocline at recreational diving depths. One of them suggested those divers who think they have encountered one must have either hit a cold current (which a diver could encounter above 60 feet as well) or have been diving below recreational dive depths (say, the Windjammer, which is at 200 feet)--athough they are not convinced even at that or greater depth that thermoclines exist here). They have made thousands of dives on Bonaire and know more about this than I do, so I intend to leave this thread now, and I am pleased that Jack feels his questions have been addressed.
Tish

Hey Tish, I was only recalling my experiences at Bari Reef. I dive with a computer which also records water temperature. Below 60 ft it always recorded a difference of about 5 F. Nothing that I would personally feel, perhaps because I was wearing the full suit, but enough to make me glad I was doing that. The most remarkable difference that I found was at Klein Bonaire at Captain Don's Reef. From 78 F at the surface to 72 F at a depth of 80 ft. But Klein is a more open water environment and the temperatures were in January. Hey oceans are dynamic bodies of water and just because one experiences temperature fluctuations one day, does not mean we'll find the same the day after. Happy diving. Coach Izzy

True Coach. My brother-in-law went down to about 150' at Playa Bengi. When he extended his arm downward at that depth, he said the water was really cold in the area of his hand about half way up his arm but was warm in the area of his elbow to his shoulder. I wonder if that was thermocline or a cold current? At the time, we thought it was a thermocline. Not really sure now after reading this thread. Just curious.

Never did Glen, Seb or I say or insinuate that one will always find thermoclines in the water around Bonaire. What we did say was that we have experienced thermoclines while diving on Bonaire.

Irregardless of the environmental conditions which create them, they do happen.

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quote:

ther·mo·cline
n.
A layer in a large body of water, such as a lake, that sharply separates regions differing in temperature, so that the temperature gradient across the layer is abrupt.

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Ah those jolly divemasters, "roaring in laughter" at the idea that their waters could harbor such a blasphemy as a thermocline. Although I believe that there's no better source of info for a place than the locals, I also learned that their information must always be taken with a grain of salt to get a more realistic picture. If we were to believe every single thing the locals said, we would have to be wary of ixtabays, aluxes, yetis, cucos, and chupacabras. I for one, encountered variances of temperatures. Like I said before, not drastic enough to make me go "Holy Cow" but they were there, with my instruments to record it. Those jolly, hearty-with-laughter divemasters do not control the behavior of the waters, no one does, no one can, thus, it's a fallacy to imply the non-existence of a phenomenom that is quite natural and common in all large bodies of water. If we are talking about probabilities now, then that's another story. I would say the likelihood of encountering a thermocline at recreational depths in Bonaire is statiscally small. Marcus, I remember I experienced something similar in Florida at the wreck of Rodeo 125 (130 feet), though I wasn't sure at the moment if it was a thermocline, or I was narced. My computer actually confirmed it. A drop of over 10F from 100 feet. Brrr! Jack, I would not be that concerned with huge temperature fluctuations if I were you. Your shorty should be sufficent within recreational depths. Keep in mind we're talking about insulation. As far as protection, I will always go for the full suit. Sea lice, sea wasps during night dives, some drifting jellies, and a few rogue fish are more than enough justification, then again, that's me. If you get a chance, Talk to Ilse Wikkeink from Bonaire Dive & Adventure (at the Sand $). She can tell you all you need to know about Bari, not to mention that she's a great instructor and guide. Happy bubble blowing! Coach Izzy

In most years in Nov, Dec, Jan or March - going down to the cave at Karpata - 120 feet - you will feel (and a good thermometer will register) a thermocline. Swim off the reef until you can just see a diver on the reef at 60 feet and you will feel a thermocline some days.
The offshore reef at Alice in Wonderland, Hilma Hooker... also can be as much as 10 degrees colder than the inshore reef. This was over 20 years diving in Bonaire.
Don't get me started on dives on the other side or near both 'ends' where currents sometimes whip! The huge barrel sponges off the NW end are wonderful but very little coral and way colder than your normal Bonaire reefs.

Tish, what's the difference between a cold current and a thermocline? Seems to me that there is none.

Here's your quote from the divemasters

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quote:

One of them suggested those divers who think they have encountered one must have either hit a cold current

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Hi, guys!
Okay, you've educated me, and now I will try to educate our local dive masters and dive instructors on the existence of local thermoclines--while hopping I never run into one.
Clearly most of us who live here do few deep dives. My deepest dive in the last week has been to 86 feet and most have not exceeded 70.
Thanks for the instruction!
However, Jack has not said he and his family were planning deep dives. He asked whether they could leave their shorties at home and dive in dive skins or whether they should bring 3 mil. shorties. I suggested they bring their shorties too. I stick by that.
Tish

Jack;
I just left Sand$ yesterday at 1PM. The vis on Bari is currently in the 40 to 80 foot range, water temp in the 80 degree range. Have fun, and try a night dive, did Sand$ to Captn Don's and back one night, was great, the two 4 to 5 foot tarpons that joined us on the trip back to Sand$ were interesting.